OpenApi: Lowercase document name on registration to match AddOpenApi internal behaviour (closes #23210) (#23212)

* Lowercase OpenAPI document name on registration to match AddOpenApi internal behaviour

AddOpenApi lowercases the document name when registering its keyed services, so
ReplaceOpenApiSchemaService must receive the same lowercased key or the lookup
throws. BackOfficeOpenApiDocumentBuilder now computes a normalised registration
name and uses it for all DI calls, while keeping DocumentName in its original
casing. ShouldInclude matches [MapToApi] case-insensitively to align with how
documents are registered, and the UI dropdown label falls back to DocumentName
(original casing) rather than the lowercased registration key.
AddUmbracoOpenApiDocument applies the same normalisation for its apiName parameter.

* Add regression tests for mixed-case OpenAPI document name registration

Covers the bug scenario where AddBackOfficeOpenApiDocument with a mixed-case
name and WithJsonOptions threw InvalidOperationException at startup, and verifies
that ShouldInclude matches [MapToApi] case-insensitively.

.claude/skills/umb-bump-version/SKILL.md

@@ -0,0 +1,94 @@
+---
+name: umb-bump-version
+description: Bump the Umbraco CMS version across all required files. Use when the user asks to bump, update, or set the version number — e.g., "bump version to 17.3.4", "set version to 18.0.0-rc", "update version". Accepts the target version as an argument.
+argument-hint: <version> (e.g., 17.3.4, 18.0.0-rc)
+---
+
+# Bump Version - Umbraco CMS
+
+Updates the Umbraco CMS version string across all files that track it.
+
+**Do NOT use AskUserQuestion if a version argument is provided. Only ask if `$ARGUMENTS` is empty or cannot be parsed as a version.**
+
+## Arguments
+
+- `$ARGUMENTS` - Required: the target version string (e.g., `17.3.4`, `18.0.0-rc`)
+
+## Files to Update
+
+The following 5 files must be updated with the new version:
+
+| # | File | Field |
+|---|------|-------|
+| 1 | `version.json` | `"version"` |
+| 2 | `src/Umbraco.Web.UI.Client/package.json` | `"version"` |
+| 3 | `src/Umbraco.Web.UI.Client/package-lock.json` | top-level `"version"` AND `packages[""].version` |
+| 4 | `tests/Umbraco.Tests.AcceptanceTest/package.json` | `"version"` |
+| 5 | `tests/Umbraco.Tests.AcceptanceTest/package-lock.json` | top-level `"version"` AND `packages[""].version` |
+
+**Note**: For major version bumps (e.g., 17.x to 18.x), `src/Umbraco.Web.UI.Login/package.json` has a caret-ranged dependency on `@umbraco-cms/backoffice` (e.g., `^17.2.0`) that will need manual updating. This skill does not handle that — major bumps involve many other changes beyond version strings.
+
+## Instructions
+
+### 1. Parse and Validate the Version
+
+Extract the version from `$ARGUMENTS`. It must be a valid semver-like string (e.g., `17.3.4`, `18.0.0-rc`, `17.4.0-preview.1`). If no version is provided or it cannot be parsed, ask the user for the target version.
+
+### 2. Read the Current Version
+
+Read `version.json` and extract the current `"version"` value. If the current version already equals the target version, report that the version is already set and stop — do not edit, stage, or commit anything.
+
+Otherwise, display both versions:
+
+```
+Bumping version: {current} -> {target}
+```
+
+### 3. Update All Files
+
+Update each of the 5 files listed above, replacing the old version with the new version. For each file:
+
+- **`version.json`**: Replace the `"version"` value.
+- **`package.json` files**: Replace the `"version"` value (near the top of the file).
+- **`package-lock.json` files**: Replace BOTH the top-level `"version"` value AND the `"version"` inside the `"packages": { "": { ... } }` block. These are always in the first ~10 lines of the file.
+
+Use targeted edits — do NOT rewrite entire files. Be precise to avoid changing version strings in dependency entries.
+
+### 4. Verify
+
+After all edits, grep for the target version value across the 5 files to confirm all updates landed correctly:
+
+```bash
+grep -n "\"version\": \"{version}\"" version.json src/Umbraco.Web.UI.Client/package.json src/Umbraco.Web.UI.Client/package-lock.json tests/Umbraco.Tests.AcceptanceTest/package.json tests/Umbraco.Tests.AcceptanceTest/package-lock.json
+```
+
+Expect exactly 7 matches (one per `package.json` and `version.json`, two per `package-lock.json`).
+
+### 5. Stage and Commit
+
+Stage only the 5 changed files:
+
+```bash
+git add version.json src/Umbraco.Web.UI.Client/package.json src/Umbraco.Web.UI.Client/package-lock.json tests/Umbraco.Tests.AcceptanceTest/package.json tests/Umbraco.Tests.AcceptanceTest/package-lock.json
+```
+
+Then commit with the message `Bump version to {version}.` — replacing `{version}` with the target version:
+
+```bash
+git commit -m "Bump version to {version}."
+```
+
+### 6. Report
+
+Output a summary:
+
+```
+Version bumped to {version} in:
+- version.json
+- src/Umbraco.Web.UI.Client/package.json
+- src/Umbraco.Web.UI.Client/package-lock.json
+- tests/Umbraco.Tests.AcceptanceTest/package.json
+- tests/Umbraco.Tests.AcceptanceTest/package-lock.json
+
+Changes staged and committed.
+```

.claude/skills/umb-release-notes/SKILL.md

@@ -0,0 +1,135 @@
+---
+name: umb-release-notes
+description: Improve a set of auto-generated GitHub release notes for an Umbraco CMS release. Cross-checks the notes against every PR carrying the release label, adds any that are missing, re-files every PR under the most appropriate category, and strips purely-internal entries. Use whenever the user asks to tidy up, improve, complete, or recategorize release notes for a given version, or mentions a release-notes text file plus a version number.
+argument-hint: <version> <path-to-generated-notes-file>
+---
+
+# Umbraco CMS - Improve Release Notes
+
+Takes a file of auto-generated GitHub release notes and produces an improved version that:
+
+1. **Is complete** — every merged PR carrying the `release/<version>` label appears.
+2. **Is well-categorized** — every PR sits under the most appropriate heading.
+3. **Is free of noise** — purely-internal entries of no value to a reader are removed.
+
+The result is written to a **new** file alongside the input, so the user can diff the two.
+
+**Run autonomously.** Do NOT use `AskUserQuestion` once the required arguments (version and input file path) are available — only ask if one of them is missing from `$ARGUMENTS` and cannot be inferred (see Arguments). Beyond that, make the categorization calls yourself using the rules below; if a handful are genuinely borderline, place them anyway and note the borderline ones in your closing summary so the user can override.
+
+## Arguments
+
+`$ARGUMENTS` contains two values:
+
+1. **Version** — e.g. `17.5.0`, `18.1.0`. The GitHub label to search is `release/<version>` (so version `17.5.0` → label `release/17.5.0`).
+2. **Input file path** — full path to the text file holding the auto-generated notes (e.g. `C:\Temp\release-17.5.0-rc.md`).
+
+If either is missing, ask the user once for the missing value, then proceed.
+
+## Prerequisites
+
+Run `gh auth status`. If it fails, tell the user to authenticate `gh` (e.g. `gh auth login`) and stop — the skill needs the GitHub CLI to query PRs. The repo is always `umbraco/Umbraco-CMS`.
+
+## Procedure
+
+### 1. Read the input notes
+
+Read the input file. Note its structure — it is GitHub's generated format:
+
+- A leading HTML comment (`<!-- Release notes generated ... -->`).
+- A `## What's Changed` heading followed by `### <emoji> <Category>` sub-headings, each with `* <title> by @<author> in <url>` bullets.
+- A trailing `## New Contributors` section and a `**Full Changelog**: ...` line.
+
+Extract the set of PR numbers already present (parse the `/pull/<number>` from each bullet). Preserve each existing bullet's **exact text** (title, author, URL) when you re-emit it — only its category placement may change.
+
+### 2. Fetch every labelled PR
+
+```bash
+gh pr list --repo umbraco/Umbraco-CMS --label "release/<version>" --state closed --limit 1000 \
+  --json number,title,author,labels,mergedAt \
+  --jq '.[] | select(.mergedAt != null) | "\(.number)\t\(.author.login)\t\([.labels[].name] | join(", "))\t\(.title)"' | sort -n
+```
+
+This is the authoritative list of what the release *should* contain. Each row gives number, author, labels, title.
+
+**Guard against silent truncation.** `gh pr list` caps at `--limit` without warning, so a large release could drop the overflow and the skill would still look "complete". Count the returned rows and compare against the limit:
+
+```bash
+gh pr list --repo umbraco/Umbraco-CMS --label "release/<version>" --state closed --limit 1000 --json number --jq 'length'
+```
+
+If this equals 1000, the limit was hit — raise `--limit` and re-fetch before continuing. Do **not** proceed on a truncated list.
+
+### 3. Reconcile
+
+- **Missing labelled PRs** (labelled but not in the input file): these must be **added**. Build a bullet as `* <title> by @<author> in https://github.com/umbraco/Umbraco-CMS/pull/<number>`.
+  - **Author handle.** `<author>` in the template is the raw `.author.login` value — the bullet supplies the leading `@`, so do not prepend another. `gh`'s `.author.login` already returns bot accounts with the `[bot]` suffix as part of the login — Dependabot comes back as `dependabot[bot]`, not `dependabot` or `app/dependabot` (the `app/` form only appears in git committer metadata and CODEOWNERS, never in `gh`'s JSON). So the login is already in the right shape; use it verbatim (e.g. `.author.login` of `dependabot[bot]` renders as `@dependabot[bot]`, matching what GitHub's generator wrote for the existing bullets). The only thing to guard against is accidentally stripping or altering the `[bot]` suffix.
+- **PRs in the file but not labelled**: keep them. The generated notes span a commit range (see the `Full Changelog` compare link), so they legitimately include backports / earlier-version PRs that lack the current label. For any of these you need to categorize, fetch its labels with:
+
+  ```bash
+  gh pr view <number> --repo umbraco/Umbraco-CMS --json number,title,labels \
+    --jq '"\(.number)\t\([.labels[].name] | join(", "))\t\(.title)"'
+  ```
+
+Do **not** invent or alter the `New Contributors` section — carry it over verbatim. You cannot reliably recompute first-time contributors, so leave it as the generator produced it (mention this in the summary).
+
+### 4. Categorize every PR
+
+Use exactly these headings, in this order. Omit any heading that ends up with no entries.
+
+| Heading | What goes here | Primary signal |
+|---|---|---|
+| `### 🙌 Notable Changes` | **Don't recategorize existing entries.** Label-driven — but still add any missing PR carrying this label here. | label `category/notable` |
+| `### 💥 Breaking Changes` | **Don't recategorize existing entries.** Label-driven — but still add any missing PR carrying this label here. | label `category/breaking` |
+| `### 📦 Dependencies` | Dependency bumps | label `dependencies`; or dependabot author |
+| `### 🚀 New Features` | New user- or developer-facing capability | label `type/feature` / `category/feature`; or title introduces/adds a genuinely new capability |
+| `### 🚤 Performance` | Performance improvements | label `category/performance`; or `Performance:` title prefix |
+| `### 🌈 Accessibility Improvements` | A11y improvements (labels, contrast, keyboard) | label `category/accessibility` / `accessibility`; or clear a11y intent (e.g. "improve contrast", "missing labels") |
+| `### 🐛 Bug Fixes` | Fixes to broken/incorrect behaviour | default for anything describing a fix |
+| `### 🧪 Testing` | Test additions/changes only | label `category/test-automation` / `area/test`; or `E2E`/`QA`/"acceptance tests"/"unit test coverage"/"add tests" titles |
+| `### 🛡️ Code Quality, Documentation and Refactoring` | Refactors, deprecations, API tidy-ups, XML/MD documentation, knowledge-base (`MD`) updates | label `category/refactor`; or titles about refactoring, deprecating, renaming, documenting, constants extraction, MD/CLAUDE.md content |
+| `### 🧑‍💻 Developer Experience` | Things that improve the experience of developers building on or contributing to Umbraco — dev tooling, build/watch ergonomics, test mocks/harnesses, backoffice dev utilities | `Developer Experience` title prefix; dev tooling; mock/harness changes |
+
+**Rules:**
+
+- **Notable and Breaking are off-limits for recategorization** — never move a PR that is *already in the input file* into or out of these sections; they are driven purely by their labels and the generator placed them correctly. This does **not** exempt them from completeness: a PR discovered as missing in step 3 that carries `category/notable` or `category/breaking` must still be **added** under the matching section.
+- Label signals beat title wording, except a `Performance:`/`Developer Experience:` title prefix is decisive for its section.
+- A PR with both `type/feature` and `category/refactor` whose title clearly describes a refactor (e.g. "swap relative imports", "re-export type") belongs under Code Quality, not New Features.
+- "Add ... tests"/"unit test coverage" → Testing, even if it also touches docs. If a PR adds XML documentation *and* tests, lead with where the title's emphasis lies (documentation → Code Quality; test coverage → Testing).
+- When a PR is genuinely 50/50, pick the more reader-useful heading and list it in your closing summary as borderline.
+
+### 5. Remove purely-internal noise
+
+Drop entries that have **no value to anyone reading release notes** — pure repository plumbing with no shipped impact. Examples:
+
+- Branch/merge maintenance ("Fix main branch after merge issue").
+- CI/pipeline fixes that don't change the product.
+- Reverts of changes that never shipped in a release.
+
+**Keep** anything that ships in the product or genuinely helps developers building on Umbraco — that includes documentation/MD updates, dev tooling, and test mocks (those go to Code Quality or Developer Experience, they are *not* noise). When unsure whether something is noise, keep it and flag it in the summary rather than silently dropping it. List every removal in your closing summary.
+
+### 6. Write the output
+
+Write to a new file in the **same folder** as the input, named by appending ` - with updates` before the extension:
+
+- Input `C:\Temp\release-17.5.0-rc.md` → Output `C:\Temp\release-17.5.0-rc - with updates.md`
+
+Preserve the leading HTML comment, the `## What's Changed` heading, the `## New Contributors` section, and the `**Full Changelog**` line exactly. Only the `### <category>` groupings and their bullets change.
+
+### 7. Report
+
+Give a concise summary:
+
+- Count of PRs added (with their numbers), and which categories they landed in.
+- Notable recategorizations (PRs moved out of the catch-all Bug Fixes into Features/Performance/Testing/etc.).
+- Every entry removed, with the one-line reason.
+- Any borderline calls the user may want to override.
+- The output file path.
+
+## Verification
+
+Before reporting done, confirm:
+
+- Every PR number from step 2 is present in the output (except any you deliberately removed in step 5 — and those must be in the removal list).
+- No PR appears under more than one heading.
+- Notable and Breaking sections are byte-for-byte unchanged from the input.
+- The header comment, New Contributors, and Full Changelog lines are intact.

.claude/skills/umb-review/SKILL.md

@@ -0,0 +1,251 @@
+---
+name: umb-review
+description: Automated PR code review for Umbraco CMS. Analyzes changed files for intent, impact on consumers, breaking changes, architecture compliance, and code quality. Non-interactive — outputs a full structured review. Use this skill whenever the user asks to review a branch, review a PR, check their changes for issues, analyze a diff, or validate breaking change patterns — even if they don't say "review" explicitly. Does NOT apply to writing new code, fixing bugs, refactoring, explaining architecture, writing tests, or reviewing documentation content.
+argument-hint: <target-branch>
+---
+
+# PR Review - Umbraco CMS
+
+Automated, non-interactive PR code review. Analyzes changed files for intent, impact on consumers, breaking changes, architecture compliance, and code quality.
+
+**Do NOT use AskUserQuestion at any point. This skill runs fully autonomously.**
+
+## Arguments
+
+- `$ARGUMENTS` - Optional: target branch to diff against (auto-detected from PR, falls back to `origin/main`)
+
+## Instructions
+
+### 0. Verify GH CLI is Available
+
+Run `gh auth status`. If it fails, read `references/gh-cli-setup.md` and present the setup instructions to the user. Do not proceed with the review.
+
+### 1. Resolve Target Branch
+
+Determine the target branch for comparison using this priority order:
+
+1. **Explicit argument**: If `$ARGUMENTS` is provided and non-empty, use it as the target branch
+2. **PR target branch**: If no argument, run `gh pr view --json baseRefName --jq '.baseRefName'` to detect the target branch of the current branch's open PR. If a PR exists, use `origin/{baseRefName}` as the target branch.
+3. **Fallback**: If no argument and no PR found (command fails or returns empty), default to `origin/main`
+
+Store the resolved target branch for use in subsequent steps. Log which resolution method was used (e.g., "Target branch: `origin/v18/dev` (from PR #1234)").
+
+### 2. Load Review Standards
+
+#### 2a. Load coding preferences
+
+Read the coding preferences and code review scoring criteria from:
+
+- `references/coding-preferences.md` (relative to this skill file)
+
+Parse and internalize all rules, conventions, scoring categories, and severity definitions. These are your review criteria.
+
+#### 2b. Load area-specific documentation
+
+Once the changed file list is known (after step 3a), determine which areas of the codebase are touched and load the relevant documentation. Execute this sub-step between 3a and 3b. This documentation takes precedence over sibling comparison for architectural and pattern validation.
+
+**Resolution order for each changed file:**
+
+1. **Find the nearest `CLAUDE.md`** — walk up from the changed file's directory toward the repository root. The first `CLAUDE.md` found is the area guide for that file. Read it.
+2. **Read referenced docs** — if the `CLAUDE.md` references documentation files (e.g., a `docs/` directory), use the descriptions in the `CLAUDE.md` to determine which docs are relevant to the type of code being changed, and read those. If unsure, read all referenced docs — the cost of reading is low, the cost of missing a convention is high.
+3. **Follow cross-references in loaded docs** — if a loaded doc references another doc as covering a complementary or related concern, and the changed files touch that concern, read the referenced doc too. Repeat until no new relevant cross-references remain.
+4. **Check for applicable skills** — review the available skills list. If a skill exists for the type of code being changed, read the skill file to understand the expected patterns, structure, and conventions it enforces. Do NOT invoke the skill — just use it as a reference for what the correct implementation should look like.
+
+**Store all loaded documentation** for use in step 4. These docs define the authoritative patterns and conventions that the review evaluates against.
+
+### 3. Gather Changed Files
+
+#### 3a. Collect file list, stats, and diff
+
+Run these git commands (where `{target}` is the resolved target branch):
+
+```bash
+git diff {target}...HEAD --name-only --diff-filter=d   # changed files (excluding deleted)
+git diff {target}...HEAD --stat                         # line counts per file
+git log {target}...HEAD --oneline                       # commit history
+git diff {target}...HEAD                                # full diff (primary review source)
+```
+
+**If no changes found**: Output "No changes found between current branch and `{target}`. Nothing to review." and stop.
+
+#### 3b. Filter out noise files
+
+From the changed file list, classify each file as **noise** or **reviewable**.
+
+**Noise files** (skip entirely — do not read, do not review):
+
+| Pattern                                              | Reason                          |
+| ---------------------------------------------------- | ------------------------------- |
+| `*.gen.ts`, `*.gen.cs`                               | Auto-generated API client code  |
+| `*.generated.cs`, `*.Designer.cs` (in `Migrations/`) | Auto-generated models/snapshots |
+| `*/assets/lang/*.ts` (except `en.ts`)                | Non-English translation files   |
+| `*/mocks/data/*.ts`                                  | Test fixture data               |
+| `*/dist-cms/*`, `*/storybook-static/*`               | Build output                    |
+| `*/TEMP/InMemoryAuto/*`                              | Runtime-generated models        |
+| `package-lock.json`                                  | Dependency lock file            |
+| `appsettings-schema.*.json`                          | Generated JSON schema           |
+
+Log the skip list: "Skipped {N} noise files: {comma-separated list of filenames}"
+
+#### 3c. Read reviewable changed files
+
+Read the full file for every reviewable changed file.
+
+#### 3d. Track file counts
+
+Keep track of these numbers for the review output in step 7: total changed files, noise files skipped, and reviewable files read. Also record: distinct production layers touched, distinct project directories, and total lines changed — these feed step 3e.
+
+#### 3e. Assess PR complexity
+
+Follow the procedure in `references/complexity-assessment.md`. Store the triggered dimensions and suggestions for step 7.
+
+#### 3f. Classify PR scope
+
+Classify the PR to determine which review steps are relevant:
+
+| Classification  | Condition                                                                       | Effect                                                                          |
+| --------------- | ------------------------------------------------------------------------------- | ------------------------------------------------------------------------------- |
+| **Gen-only**    | All reviewable files are `gen.ts`                                               | Skip steps 5 and 6; step 4 reviews impact on other code only                    |
+| **Docs-only**   | All reviewable files are `.md`                                                  | Skip steps 5 and 6; step 4 reviews intent and readability only                  |
+| **Test-only**   | All reviewable files are in `tests/`                                            | Skip steps 5 and 6; step 4 reviews intent, code quality, and test coverage only |
+| **Config-only** | All reviewable files are `.csproj`, `.props`, `.json` config, or CI/build files | Skip step 5; step 6 checks dependency version changes only                      |
+| **Standard**    | Anything else                                                                   | No skips — run all steps                                                        |
+
+### 4. Raw Code Review
+
+Review each changed file holistically. Think like a senior developer reading a colleague's PR. Note all findings without worrying about format or severity yet.
+
+#### 4a. Read and reason about each file
+
+For each changed file, reason about: What does this code do? Is it correct? What's missing — validation, error handling, notifications, cleanup, edge cases? Could this break anything for consumers?
+
+#### 4b. Validate against documentation and patterns
+
+Use a **docs-first** approach: classify the code by what it does, check it against documented conventions, and only fall back to sibling comparison when docs don't cover the pattern.
+
+**Step 1 — Determine the correct approach from documentation, then check whether the PR matches**
+
+A PR is a proposed solution, not the source of truth. This step has two parts that must happen in order — do not start part B until part A is complete.
+
+**Part A — Before validating/judging the implementation**, determine what the correct approach is for each new class or file based on what it does. Use the documentation loaded in step 2b to identify the expected base classes, patterns, and conventions. Write down the expected approach. Classify based on what the code does, not based on what neighboring files look like.
+
+**Part B — Now compare the PR's implementation** against the expected approach from Part A. If it deviates from the documented approach, flag it. If the documentation specifies reference examples, read those examples to verify the implementation matches.
+
+**Pattern match is the leading finding.** If the documentation defines a pattern that fits what the code does, the first and most important finding is whether the code follows that pattern.
+
+**Step 2 — Fall back to sibling comparison**
+
+If the documentation does not cover the specific pattern, or for cross-cutting concerns not addressed in docs, fall back to sibling comparison:
+
+1. **New method on existing class/interface**: Grep for the most similar existing method on the same class using `-A 80` to capture the full method body (e.g., `UpdateCurrentUserAsync` → grep for `UpdateAsync` in the same file with `-A 80`). Compare line by line for missing cross-cutting concerns: notifications/events, validation, scoping, authorization, error handling, audit logging.
+2. **New TS class**: Grep for siblings by base class (`extends {BaseClass}`) or by interface (`implements {Interface}`) or by name suffix (e.g., `CurrentUserController` → grep for `UserController`). Compare for missing concerns.
+3. **New CS class**: Grep for siblings by base class (`class {ClassName} : {BaseClass}`) or by interface (`class {ClassName} : {Interface}`) or by name suffix (e.g., `ManagementApiComposer` → grep for `ApiComposer`). Compare for missing concerns.
+
+**Important:** Sibling comparison validates cross-cutting concerns, but it must not override documented conventions. If a sibling deviates from documented patterns, that sibling is wrong — do not copy its deviation.
+
+Store your raw findings — they feed into step 7.
+
+### 5. Impact Analysis
+
+**Skip this step if PR scope is docs-only, test-only, or config-only.**
+
+Follow the procedure in `references/impact-analysis.md`.
+
+### 6. Breaking Changes Check
+
+**Skip this step if PR scope is docs-only or test-only. If config-only, only check for dependency version changes that could break consumers.**
+
+Follow the procedure in `references/breaking-changes.md`.
+
+### 7. Consolidate and Output Review
+
+Merge findings from step 4 (raw review), step 5 (impact analysis), and step 6 (breaking changes). For each finding, assign severity (Critical/Important/Suggestion) and verify it relates to changed code — not pre-existing issues. Before outputting, drop any finding about whitespace, blank lines, formatting, or comment wording. Then present the review in this exact format:
+
+```markdown
+## PR Review
+
+**Target:** `{target_branch}` · **Based on commit:** `{head_sha}`
+[If any skipped files, append: · **Skipped:** {skipped} files out of {total} total]
+[If step 3f classification is not "Standard", append: · **Classified as:** {classification}]
+
+[1–2 sentences: what this PR accomplishes , keep it as short as possible, only highlight the primary essence.]
+
+- **Modified public API:** {changed existing interfaces/types/classes/methods}
+  [Omit bullet if none]
+- **Affected implementations (outside this PR):** {interfaces/types/classes/methods using modified public API}
+  [Omit bullet if none]
+- **Breaking changes:** {violations with specifics}
+  [Omit bullet if none]
+- **Other changes:** {changes not listed above that an Umbraco user, plugin developer, or API consumer would notice — e.g., behavior changes, default value changes, error message changes, new configuration options, removed functionality. Exclude internal renames, formatting, and private implementation details.}
+  [Omit bullet if none]
+
+[If step 3e triggered any dimensions, insert this block. Omit entirely if nothing triggered:]
+
+> [!NOTE]
+> **Complexity advisory** — This PR may benefit from splitting.
+>
+> - **{Dimension}:** {Explanation and concrete split suggestion from step 3e}
+>   [one bullet per triggered dimension]
+>
+> _This is an observation, not a blocker. The full review follows below._
+
+---
+
+### Critical
+
+[Must fix before merge — security vulnerabilities, data loss, broken functionality, breaking changes without proper patterns]
+
+- **`{file}:{line}`**: {problem} → {fix}
+
+[Omit section if none]
+
+### Important
+
+[Should fix — performance issues, missing tests, architectural violations, pattern misuse]
+
+- **`{file}:{line}`**: {observation} → {suggestion}
+
+[Omit section if none]
+
+### Suggestions
+
+[Nice to have — readability, minor refactoring, alternative approaches]
+
+- **`{file}:{line}`**: {detail}
+
+[Omit section if none]
+
+---
+
+[One of:]
+
+## Approved
+
+This looks good to be merged as-is, but please do a manual sanity check and testing before merging.
+
+## Approved with Suggestions for improvement
+
+Good to go, but please carefully consider the importance of the suggestions.
+
+## Request Changes
+
+Critical and important issues must be addressed first.
+
+## Needs re-work
+
+This is in such a bad state that the feedback of this review is not sufficient to guide improvements, the PR cannot be approved.
+```
+
+**Guidelines for the review output:**
+
+— When reporting information, be extremely concise and sacrifice grammar for sake of concision.
+
+- Only review code that was changed in the diff — pre-existing issues are out of scope. Focus on what compilers and linters cannot catch: behavioral side-effects (e.g., a changed default alters runtime behavior for consumers), architectural violations (e.g., a new dependency breaks layering), breaking changes for external consumers of the public API, and security implications. Leave type errors, missing imports, and broken references to CI.
+- Be specific — always reference file and line number
+- Explain WHY something is an issue, not just WHAT, but avoid stating the obvious.
+- For complex matters, provide concrete fix suggestions, including code snippets when helpful
+- Keep it constructive — the goal is to help, not gatekeep
+- Don't repeat the same finding for every occurrence — mention it once and note "same pattern in {other files}"
+- Focus on substantive issues only. Do NOT flag purely cosmetic or stylistic concerns. Specifically, never flag: code formatting or whitespace, comment grammar or wording, redundant-but-harmless syntax (e.g., optional chaining after a truthiness check), code duplication that doesn't cause bugs, or HTML template cosmetics. The only exception is when a stylistic issue has a concrete impact on performance or rendering. Note: missing JSDoc/documentation on public or exported APIs is a substantive finding (per coding preferences), not a cosmetic one — flag it as a Suggestion.
+- For breaking changes, reference the specific pattern from the CLAUDE.md that should be applied
+- Do not suggest changes that would themselves introduce breaking changes. If a suggestion would alter public API surface (e.g., changing return types, renaming public members), it is not appropriate for a PR targeting `main` within a major version. Only suggest non-breaking alternatives.

.claude/skills/umb-review/evals/evals.json

@@ -0,0 +1,97 @@
+{
+  "skill_name": "umb-review",
+  "evals": [
+    {
+      "id": 0,
+      "name": "pr-22214-large-frontend-refactor",
+      "prompt": "Review the changes in PR #22214 (branch origin/pr/22214 targeting main). This is a large frontend refactor migrating create entity actions to use entityCreateOptionAction extensions, with deprecations.",
+      "expected_output": "A structured review that identifies frontend deprecation patterns, flags the large PR complexity, handles 75+ files correctly, checks for breaking changes in exported components, and produces the correct output format.",
+      "pr_number": 22214,
+      "pr_branch": "origin/pr/22214",
+      "base_branch": "origin/main",
+      "files": [],
+      "assertions": [
+        {"id": "deprecation-patterns-noted", "text": "Review identifies deprecation patterns (@deprecated, UmbDeprecation)"},
+        {"id": "frontend-breaking-change-awareness", "text": "Checks frontend-specific breaking changes (exports, custom elements) not just backend"},
+        {"id": "file-references-present", "text": "Findings reference specific files with line numbers"},
+        {"id": "no-false-critical-on-deprecations", "text": "Properly deprecated code is NOT flagged as Critical breaking change"},
+        {"id": "no-stylistic-nitpicks", "text": "Review does not flag purely cosmetic/stylistic issues (formatting, whitespace, naming conventions, comment grammar, code style preferences) unless they affect performance or rendering. Missing JSDoc on new public APIs is NOT a stylistic issue — it is a legitimate finding."},
+        {"id": "manifest-alias-rename-detected", "text": "Alias renames (CreateOptions → Create) flagged as Critical breaking change"},
+        {"id": "non-exported-deletions-dismissed", "text": "Deleted action classes NOT flagged as breaking (verified against package.json exports)"},
+        {"id": "noise-files-filtered", "text": "Does not review noise files (generated files, lock files, etc.)"},
+        {"id": "complexity-advisory-triggers", "text": "Review includes a complexity/split advisory for the large 75+ file scope"}
+      ]
+    },
+    {
+      "id": 1,
+      "name": "pr-21672-small-frontend-bugfix",
+      "prompt": "Review the changes in PR #21672 (branch origin/pr/21672 targeting main). This is a small 4-file frontend bugfix implementing tab validation badges in the block editor.",
+      "expected_output": "A clean review that correctly identifies this as a small focused bugfix, avoids false positives, and either approves or approves with minor suggestions.",
+      "pr_number": 21672,
+      "pr_branch": "origin/pr/21672",
+      "base_branch": "origin/main",
+      "files": [],
+      "assertions": [
+        {"id": "complexity-advisory-absent", "text": "Review does NOT include a complexity/split advisory"},
+        {"id": "no-false-breaking-changes", "text": "Review does not flag breaking changes"},
+        {"id": "proportionate-verdict", "text": "Verdict is 'Request Changes'"},
+        {"id": "concise-review", "text": "Review output is under 200 lines"},
+        {"id": "no-stylistic-nitpicks", "text": "Review does not flag purely cosmetic/stylistic issues (formatting, whitespace, naming conventions, comment grammar, code style preferences) unless they affect performance or rendering. Missing JSDoc on new public APIs is NOT a stylistic issue — it is a legitimate finding."}
+      ]
+    },
+    {
+      "id": 2,
+      "name": "pr-22217-small-backend-webhook",
+      "prompt": "Review the changes in PR #22217 (branch origin/pr/22217 targeting v18/dev). This is a tiny 3-file backend change to the default webhook payload type.",
+      "expected_output": "A concise review that correctly resolves v18/dev as target branch, handles the small change proportionately, and considers the behavioral impact of changing a default value.",
+      "pr_number": 22217,
+      "pr_branch": "origin/pr/22217",
+      "base_branch": "origin/v18/dev",
+      "files": [],
+      "assertions": [
+        {"id": "correct-target-branch", "text": "Review references 'v18/dev' as the target branch (not 'main')"},
+        {"id": "default-value-change-noted", "text": "Review discusses the behavioral impact of changing the default payload type"},
+        {"id": "proportionate-review", "text": "Review output is under 150 lines"},
+        {"id": "no-stylistic-nitpicks", "text": "Review does not flag purely cosmetic/stylistic issues (formatting, whitespace, naming conventions, comment grammar, code style preferences) unless they affect performance or rendering. Missing JSDoc on new public APIs is NOT a stylistic issue — it is a legitimate finding."},
+        {"id": "ignores-preexisting-issues", "text": "Does NOT flag the ~30 builder extension methods with Legacy defaults (pre-existing, not changed in the PR)"},
+        {"id": "side-effect-detection", "text": "Flags stale WebhookSettings.cs docs as a side-effect of the constant value change"},
+        {"id": "consumer-identification", "text": "Identifies affected consumers outside the PR (WebhookSettings, UmbracoBuilder, or WebhookEventCollectionBuilderExtensions)"}
+      ]
+    },
+    {
+      "id": 3,
+      "name": "pr-22268-frontend-feature-workspace-modal",
+      "prompt": "Review the changes in PR #22268 (branch origin/pr/22268 targeting main). This is a 29-file frontend feature adding a current user workspace modal.",
+      "expected_output": "A review of a medium-sized new feature PR. Should assess the new code for architectural compliance, check for breaking changes (new exports, custom elements), and evaluate code quality without flagging pre-existing issues.",
+      "pr_number": 22268,
+      "pr_branch": "origin/pr/22268",
+      "base_branch": "origin/main",
+      "files": [],
+      "assertions": [
+        {"id": "complexity-advisory-triggers", "text": "Review includes a complexity/split advisory (3 layers: Core, API, Frontend across 27+ files)"},
+        {"id": "breaking-changes-on-interface-additions", "text": "Flags new interface methods without default implementations as breaking changes (Pattern 3)"},
+        {"id": "no-stylistic-nitpicks", "text": "Review does not flag purely cosmetic/stylistic issues unless they affect performance or rendering. Missing JSDoc on new public APIs is NOT a stylistic issue — it is a legitimate finding."},
+        {"id": "diff-scoped", "text": "All findings reference code that was changed in the diff, not pre-existing issues"},
+        {"id": "new-feature-assessed", "text": "Review assesses the new feature's architecture, patterns, or integration approach — not just absence of bugs"},
+        {"id": "no-false-notification-finding", "text": "Review does NOT flag UpdateCurrentUserAsync as missing UserSavingNotification/UserSavedNotification — the sibling UpdateAsync also does not publish these notifications, so flagging their absence would be a false positive"}
+      ]
+    },
+    {
+      "id": 4,
+      "name": "pr-22215-frontend-architecture-violation",
+      "prompt": "Review the changes in PR #22215 (branch origin/pr/22215 targeting main). This is a 2-file frontend feature adding user management to the user group workspace.",
+      "expected_output": "A review that catches the architecture violation: the workspace context directly imports and calls UserService and UserGroupService (generated API clients) instead of going through a repository. In the Umbraco backoffice, workspace contexts access data via repositories, not by calling API services directly. The review should flag this as a significant architecture issue and request changes.",
+      "pr_number": 22215,
+      "pr_branch": "origin/pr/22215",
+      "base_branch": "origin/main",
+      "files": [],
+      "assertions": [
+        {"id": "service-bypass-detected", "text": "Review flags that the workspace context directly imports/calls UserService or UserGroupService instead of using a repository"},
+        {"id": "repository-pattern-recommended", "text": "Review recommends using the repository pattern (going through a repository/data-source layer) rather than calling API services directly from the workspace context"},
+        {"id": "verdict-request-changes", "text": "Verdict is 'Request Changes' (the architecture violation warrants requesting changes, not just approving with suggestions)"},
+        {"id": "no-stylistic-nitpicks", "text": "Review does not flag purely cosmetic/stylistic issues (formatting, whitespace, naming conventions, comment grammar, code style preferences) unless they affect performance or rendering. Missing JSDoc on new public APIs is NOT a stylistic issue — it is a legitimate finding."},
+        {"id": "no-false-breaking-changes", "text": "Review does not flag breaking changes (this PR only adds new code, no public API is removed or modified)"}
+      ]
+    }
+  ]
+}

.claude/skills/umb-review/references/breaking-changes.md

@@ -0,0 +1,249 @@
+# Breaking Changes Reference
+
+This document describes how to detect and validate breaking changes during PR review. It covers both backend (.NET) and frontend (TypeScript/Lit) patterns.
+
+---
+
+## Version Detection
+
+**Always read `version.json`** at the repository root to determine the current major version. This drives the obsolete removal target calculation:
+
+- Current major version: read from `version.json` → `version` field (e.g., `"17.4.0-rc"` → major version `17`)
+- Obsolete removal target: `current + 2` (e.g., if current is 17, removal is scheduled for Umbraco 19)
+- Format: `[Obsolete("... Scheduled for removal in Umbraco {current+2}.")]`
+
+---
+
+## Backend (.NET) Breaking Changes
+
+### What Constitutes a Breaking Change
+
+Any of these on a `public` or `protected` member:
+
+- Removing or renaming a class, interface, struct, record, or enum
+- Removing or renaming a method, property, or field
+- Changing a method signature (parameters, return type)
+- Adding required parameters to an existing method
+- Adding methods to a public interface (without default implementation)
+- Changing a constructor signature on a public class
+- Removing or changing enum values
+- Changing type hierarchy (base class, implemented interfaces)
+
+### Pattern 1: Obsolete Constructor + StaticServiceProvider
+
+When a public class needs new dependencies, the existing constructor must be preserved.
+
+**Correct pattern:**
+
+```csharp
+[Obsolete("Please use the constructor with all parameters. Scheduled for removal in Umbraco 19.")]
+public MyService(IDependencyA depA)
+    : this(
+        depA,
+        StaticServiceProvider.Instance.GetRequiredService<IDependencyB>())
+{
+}
+
+public MyService(IDependencyA depA, IDependencyB depB)
+{
+    _depA = depA;
+    _depB = depB;
+}
+```
+
+**Validation checklist:**
+
+- [ ] Old constructor has `[Obsolete]` attribute with correct removal version
+- [ ] Old constructor calls new constructor via `: this(...)`
+- [ ] `StaticServiceProvider.Instance.GetRequiredService<T>()` used for new params only
+- [ ] DI registration uses the NEW constructor (old is for external consumers only)
+- [ ] Removal version is `{current_major + 2}`
+
+**Common mistakes to flag:**
+
+- Removing the old constructor entirely (breaking change!)
+- Old constructor NOT calling new constructor (code duplication)
+- Wrong removal version in `[Obsolete]`
+- Missing `StaticServiceProvider` resolution for new dependencies
+- DI registration still using the old constructor
+
+### Pattern 2: Obsolete Method + New Overload
+
+When a method signature needs to change, add the new overload and obsolete the old.
+
+**Correct pattern:**
+
+```csharp
+[Obsolete("Use the overload taking all parameters. Scheduled for removal in Umbraco 19.")]
+public void DoThing(string name)
+    => DoThing(name, extraParam: null);
+
+public void DoThing(string name, string? extraParam)
+{
+    // Real implementation here
+}
+```
+
+**Validation checklist:**
+
+- [ ] Old method has `[Obsolete]` attribute with correct removal version
+- [ ] Old method calls new method, providing defaults for new parameters
+- [ ] All internal callers updated to use the new method
+- [ ] No internal code references the obsolete method (except the delegation)
+
+### Pattern 3: Default Interface Implementation
+
+When adding methods to a public interface, provide a default implementation.
+
+**Correct pattern:**
+
+```csharp
+public interface IMyService
+{
+    void ExistingMethod();
+
+    // New method with default implementation
+    void NewMethod(string param)
+        => ExistingMethod(); // delegate to existing if possible
+}
+```
+
+**Strategies for defaults (in order of preference):**
+
+1. Use existing interface methods to satisfy the contract
+2. Return a sensible default (empty collection, null, etc.)
+3. Throw `NotImplementedException` if no reasonable default exists
+
+**Validation checklist:**
+
+- [ ] New interface method has a default implementation
+- [ ] TODO comment present: `// TODO (V{next-major}): Remove the default implementation when {obsolete method} is removed.`
+- [ ] Default implementation is functionally correct (even if not optimal)
+- [ ] If `StaticServiceProvider` is used in default impl, noted as temporary
+
+### Obsolete Attribute Validation
+
+For any `[Obsolete]` attribute found in changed code:
+
+1. **Format**: Must contain `"Scheduled for removal in Umbraco {version}."`
+2. **Version**: Must be `current_major + 2` (read from `version.json`)
+3. **Pragma**: Where obsolete members must call each other, `#pragma warning disable CS0618` / `#pragma warning restore CS0618` must be present
+
+### Internal Caller Check
+
+After finding obsolete patterns, verify:
+
+- Search the codebase for usages of the obsolete member
+- **No internal code** (inside `src/`) should reference obsolete members
+- Only the obsolete member's own delegation (calling the new version) is acceptable
+- External consumers (outside the repo) get the deprecation period to migrate
+
+---
+
+## Frontend (TypeScript/Lit) Breaking Changes
+
+The backoffice is published as `@umbraco-cms/backoffice` with 140+ named exports. Plugin developers depend on this public API surface.
+
+**Critical frontend rule (does not apply to backend .NET where `public`/`protected` visibility determines the API surface): only symbols reachable through the `package.json` `exports` field are public API.** Anything not exported — whether classes, functions, constants, types, or entire files — is an internal implementation detail, even if other internal code imports it. Removing or changing unexported frontend symbols is not a breaking change. Before flagging a frontend deletion or rename as breaking, verify the symbol is reachable via `package.json` exports. If it is not, do not flag it.
+
+### Custom Elements (Web Components)
+
+**Breaking changes:**
+
+- Renaming or removing a registered custom element tag (`umb-*`)
+- Removing elements from `HTMLElementTagNameMap`
+- Removing or changing `@property()` decorated fields on exported components
+- Removing event emissions (checked via `this.dispatchEvent`)
+- Removing CSS custom properties (`@cssprop` in JSDoc)
+- Removing CSS parts (`@csspart` in JSDoc)
+
+**How to detect:**
+
+- Check diff for removed `@customElement('umb-...')` decorators
+- Check diff for removed `@property()` fields on exported components
+- Check diff for removed entries in `HTMLElementTagNameMap` declarations
+
+### Exported Types/Interfaces
+
+**Breaking changes:**
+
+- Removing exports from `package.json` `exports` field
+- Changing the shape of exported interfaces (removing properties, changing types)
+- Renaming exported types (consumers import by name)
+- Removing union type members
+- Changing generic type parameter constraints
+
+**How to detect:**
+
+- Check if `package.json` `exports` field is modified
+- Check diff for removed `export` statements
+- Check diff for changed interface/type shapes
+
+### Manifest/Extension System
+
+**Breaking changes:**
+
+- Renaming a manifest `alias` value — plugin developers reference aliases by string in conditions, overwrites, and extension registry lookups. Alias renames are not caught by the compiler since they are string-based. A renamed alias silently breaks any plugin that references the old string.
+- Removing support for a manifest `type` that plugins use
+- Changing manifest `alias` resolution or validation
+- Removing or renaming manifest `kind` types
+- Changing extension bundle structure
+
+**How to detect:**
+
+- **Alias renames**: Compare `alias:` values in manifest files before and after. Changed alias strings are Critical — the old alias should be preserved as a deprecated entry.
+- Search for changes to manifest type definitions
+- Check for removed or renamed manifest kinds
+
+### Context API
+
+**Breaking changes:**
+
+- Removing context tokens from exports
+- Changing the shape of data provided by a context
+- Removing context provider/consumer mechanisms
+
+**How to detect:**
+
+- Check for removed context token exports
+- Check for changes to context provider classes
+
+### Controllers/Lifecycle
+
+**Breaking changes:**
+
+- Changing controller base class inheritance requirements
+- Removing controller lifecycle hooks
+- Breaking cleanup mechanisms in `disconnectedCallback()`
+
+### Observable/State
+
+**Breaking changes:**
+
+- Removing observable properties from the public API
+- Changing observable emission patterns
+
+### npm Publishing
+
+**Breaking changes:**
+
+- Changing version constraints that exclude previously-supported versions
+- Adding incompatible peer dependency constraints
+
+**How to detect:**
+
+- Check if `package.json` `peerDependencies` or `dependencies` changed
+- Verify version ranges are not narrowed
+
+---
+
+## Reporting Breaking Changes
+
+When a breaking change is detected, report:
+
+1. **What**: The specific change and which public symbol is affected
+2. **Pattern**: Which mitigation pattern should be applied (Pattern 1, 2, or 3 for backend)
+3. **Severity**: Critical (no mitigation present) or Important (mitigation present but incorrect)
+4. **Fix**: Concrete code suggestion showing the correct pattern
+
+If no breaking changes are detected, state: "No breaking changes detected."

.claude/skills/umb-review/references/coding-preferences.md

@@ -0,0 +1,168 @@
+# Coding Preferences & Review Criteria
+
+These are the coding preferences and code review standards used by the review skill. They define what the review evaluates against.
+
+---
+
+## Testing
+
+- **Always create blackbox tests** for new/changed code
+- Choose the appropriate test level:
+  - **Unit tests** for isolated logic
+  - **Integration tests** for application services/use cases
+  - **E2E tests** for API endpoints
+
+### Test Class Naming
+
+- Test classes must be postfixed with `Tests` (e.g., `OrderServiceTests`)
+- One test class per class under test
+
+### Test Method Naming
+
+**C# tests**: Use the `Can_`/`Cannot_` pattern with PascalCase underscore-separated words:
+
+- `Can_Schedule_Publish_Invariant`
+- `Cannot_Delete_Non_Existing`
+- `Can_Schedule_Publish_Single_Culture`
+
+Large test classes are split into partial files by method: `ContentServiceTests.Delete.cs`, `ContentServiceTests.Publish.cs`.
+
+**TypeScript tests**: Use BDD-style `it()` with natural language descriptions:
+
+- `it('should not allow the returned value to be lower than min')`
+- `it('converts string to camelCase')`
+
+### Unit Tests
+
+- Optional, but must be blackbox tests so refactoring does not break tests
+
+### Integration Tests
+
+- Every use case / application service must have integration tests
+- Tests run against real database (containerized or similar)
+- Test the full flow from application layer through infrastructure
+
+### E2E Tests
+
+- Every API endpoint must have E2E tests
+- Test realistic scenarios including error cases
+
+---
+
+## Trade-offs
+
+When making decisions, prioritize:
+
+- **Readability** over cleverness
+- **Flexibility** over rigidity
+- Explain trade-offs when deviating from these defaults
+
+---
+
+## Breaking Changes
+
+- Communicate breaking changes at the **OpenAPI/openapi.json level**
+- Clearly document what changed and the migration path
+
+---
+
+## Documentation
+
+- **Document all public or exported types** (classes, interfaces, types, methods, properties)
+- Keep documentation in sync with code changes
+- Add **JS Docs** on all public frontend APIs (classes, methods, properties)
+- Focus on "why" and usage, not restating the obvious
+
+---
+
+## Dependencies
+
+- Use what's available in the codebase, unless there is no good choice
+- **Flag new dependencies** for review — new packages should be justified
+- Prefer well-maintained, widely-used packages
+
+---
+
+## Error Messages & Logging
+
+- **User-facing errors**: Clear, friendly, actionable
+- **Log messages**: Technical, detailed, with context
+- Include correlation IDs and relevant data in logs
+
+---
+
+## Security
+
+- **Always check for security issues** using OWASP Top 10 as baseline
+- Flag potential vulnerabilities immediately
+- Suggest secure alternatives when spotting risky patterns
+- Apply principle of least privilege
+
+---
+
+## Immutability
+
+- Prefer **immutability** by default
+- Allow internal properties to be mutated, as long as they are not direct references coming from the outside
+
+---
+
+## Nullability
+
+- **TypeScript / JavaScript**
+  - Prefer `undefined` for optional/omitted values (e.g., optional parameters, props, and fields)
+  - Use `null` only when the domain model explicitly encodes "no value" or "not set" (e.g., `string | null` from APIs/DB), and be consistent with existing types
+  - Avoid mixing `null` and `undefined` for the same concept within the same model or API surface
+  
+- **C#**  
+  - use nullable types (e.g., `string?`, `int?`) where absence is valid
+  - Prefer domain modeling (value objects, options/results, empty collections) over `null` where appropriate, but respect existing conventions in the codebase
+
+---
+
+## C# Specific
+
+- use Notification pattern (not C# events), Composer pattern (DI registration), Scoping with `Complete()`, Attempt pattern for operation results.
+
+---
+
+## Architecture
+
+- Follow **Clean Architecture** principles
+- **Fail-fast** principle: detect and report errors as early as possible
+- Within the established layered architecture (Core/Infrastructure/Web/API), organize code by feature inside each layer where practical, while preserving dependency direction
+- One class per file
+- Avoid N+1 queries
+- Profile before optimizing non-critical paths
+
+### Type Hierarchy Consistency
+
+When parallel model types have inconsistent relationships to a shared base type:
+
+**TypeScript**: manipulations via `Omit`, `Pick`, intersection overrides, or workarounds like `as unknown as` / double-casts to bridge type mismatches.
+
+**C#**: hiding base members with `new` to change types, explicit interface implementations to mask mismatches, or downcasting base return types in derived classes.
+
+- **Do NOT suggest** the PR code should deviate from its base type to match a sibling that already deviates. Copying the deviation spreads the problem.
+- **Do flag** the architectural inconsistency: parallel models should share a compatible base contract. The model that manipulates or deviates from the base type is the one that needs attention — not the one that extends it correctly.
+- **Frame the suggestion** as: "These related models have inconsistent type hierarchies. `{deviating type}` manipulates the base contract of `{base type}`, which forces shared consumers like `{shared utility}` to require a shape that conforming subtypes can't satisfy."
+
+---
+
+## Code Style
+
+- Follow standard naming conventions for the language (C# or JS/TS)
+- Keep components small and focused on a single responsibility
+- Prefer early returns
+- Small functions
+- No nested ternaries
+
+---
+
+## Severity Levels
+
+| Severity | Meaning |
+|----------|---------|
+| **Critical** | Must fix before merge — security vulnerabilities, data loss risks, broken functionality |
+| **Important** | Should fix — performance issues, missing tests, architectural violations |
+| **Suggestion** | Nice to have — readability, minor refactoring, alternative approaches |

.claude/skills/umb-review/references/complexity-assessment.md

@@ -0,0 +1,33 @@
+# PR Complexity Assessment
+
+Evaluate whether the PR's scope suggests it should be split. This assessment is **informational only** — it never blocks or shortens the review.
+
+## Always check: Formatting mixed with logic
+
+This check applies to every PR regardless of size or scope.
+
+Run both commands and compare per-file line counts:
+```bash
+git diff {target}...HEAD --stat
+git diff {target}...HEAD --stat --ignore-all-space
+```
+
+For any file where the whitespace-ignored diff is less than **half** the full diff size (and the full diff is over 50 lines), that file has significant formatting changes mixed with logic. Flag it with a split suggestion: "File(s) {list} contain significant formatting changes mixed with logic. Consider a separate formatting-only commit or PR to keep the functional diff reviewable."
+
+## Multi-project scope check
+
+Skip this section entirely if ALL production files reside in a single project directory or if the PR is docs-only, test-only, dependency-bump-only, or rename-only.
+
+Otherwise, flag any dimension that applies:
+
+| Dimension | Condition | Suggestion |
+|---|---|---|
+| **Size** | 30+ files OR 1500+ lines, spanning 2+ projects | "If changes in {projectA} and {projectB} are independently functional, they could be separate PRs." |
+| **Layer spread** | 3+ layers touched (Core/Infrastructure/Web/API/Frontend), 10+ files | "Consider splitting by layer — e.g., Core+Infrastructure first, then API/Frontend consumers." |
+| **Mixed intent** | 2+ intent categories (new feature, bugfix, refactor, dependency update) with 15+ files or 3+ projects | "Consider extracting the {secondary intent} into a separate PR." |
+
+Intent categories — detect from diff characteristics, not commit messages:
+- **New feature**: new files or new `public`/`export` declarations
+- **Bug fix**: small targeted edits, no new files (don't co-flag with new feature)
+- **Refactor**: file renames, symbols moved but logic unchanged
+- **Dependency update**: changes to `.csproj`, `Directory.Packages.props`, `package.json`

.claude/skills/umb-review/references/gh-cli-setup.md

@@ -0,0 +1,23 @@
+# GH CLI Setup Instructions
+
+The GitHub CLI (`gh`) is required for this review skill to detect PR target branches.
+
+## Installation
+
+Install via Homebrew:
+
+```
+brew install gh
+```
+
+Or see https://cli.github.com/ for other installation methods.
+
+## Authentication
+
+After installing, authorize by running this in the terminal (use the `!` prefix in Claude Code):
+
+```
+! gh auth login
+```
+
+Follow the prompts to authenticate with your GitHub account.

.claude/skills/umb-review/references/impact-analysis.md

@@ -0,0 +1,153 @@
+# Impact Analysis Reference
+
+This document describes how to perform impact analysis during PR review. The goal is to look beyond the diff to understand how changes affect consumers in other parts of the codebase.
+
+---
+
+## 1. Extract Changed Public Symbols
+
+Scan the diff output for changes to public API surface:
+
+### Backend (.NET)
+
+Look for added, modified, or removed lines containing:
+
+- `public class`, `public abstract class`, `public sealed class`
+- `public interface`
+- `public record`, `public struct`, `public enum`
+- `public` or `protected` methods, properties, fields
+- `public static` members
+- Constructor signatures on public types
+
+### Frontend (TypeScript/Lit)
+
+Look for changes to:
+
+- `export class`, `export interface`, `export type`, `export enum`
+- `export function`, `export const`
+- `@property()` decorated fields on exported components
+- `@customElement()` registrations
+- Entries in `package.json` `exports` field
+
+Collect a list of all changed public symbol names (type names, method names, property names).
+
+---
+
+## 2. Search for Consumers
+
+For each changed public symbol, search the `src/` directory for usages **outside the changed file itself**.
+
+### Grep Strategy
+
+Use the Grep tool with these settings:
+
+```
+pattern: {symbol name}
+path: src/
+output_mode: files_with_matches
+head_limit: 20
+```
+
+Use `head_limit: 20` to avoid overwhelming results — if there are more than 20 consumers, note "20+ consumers found" and list the first 20.
+
+### What to Search For
+
+For each changed type/method, search for:
+
+- **Type references**: class name, interface name (e.g., `IContentService`)
+- **Method calls**: method name in context (e.g., `\.GetById\(` for a method rename)
+- **Constructor usage**: `new TypeName(`
+- **DI registrations**: `.AddSingleton<IType, Type>`, `.AddScoped<`, `.AddTransient<`
+- **Notification handlers**: if a notification type changed, search for `INotificationHandler<NotificationTypeName>` and `INotificationAsyncHandler<NotificationTypeName>`
+- **Interface implementations**: if an interface changed, search for `: IInterfaceName` or `IInterfaceName,`
+
+### Excluding the Changed File
+
+When reporting consumers, exclude files that are part of the PR's changes (they're already being reviewed). The interesting consumers are those **outside** the PR that may be affected.
+
+---
+
+## 3. Check Dependency Flow Direction
+
+The Umbraco architecture enforces strict unidirectional dependencies:
+
+```
+Api.Management / Api.Delivery (depend on Api.Common)
+  ↓
+Api.Common (depends on Web.Common)
+  ↓
+Web.Common (depends on Infrastructure)
+  ↓
+Infrastructure (depends on Core)
+  ↓
+Core (no dependencies)
+```
+
+### Layer Mapping
+
+Map each changed file to its architectural layer:
+
+| Path prefix | Layer |
+|---|---|
+| `src/Umbraco.Core/` | Core |
+| `src/Umbraco.Infrastructure/` | Infrastructure |
+| `src/Umbraco.PublishedCache.*` | Infrastructure |
+| `src/Umbraco.Examine.Lucene/` | Infrastructure |
+| `src/Umbraco.Cms.Persistence.*` | Infrastructure |
+| `src/Umbraco.Web.Common/` | Web |
+| `src/Umbraco.Web.UI/` | Web (Application) |
+| `src/Umbraco.Web.Website/` | Web |
+| `src/Umbraco.Cms.Api.Common/` | API |
+| `src/Umbraco.Cms.Api.Management/` | API |
+| `src/Umbraco.Cms.Api.Delivery/` | API |
+| `src/Umbraco.Web.UI.Client/` | Frontend |
+| `tests/` | Test |
+
+### Violation Detection
+
+Flag if a change introduces:
+
+- **Core depending on Infrastructure**: Core file importing/referencing Infrastructure types
+- **Core depending on Web/API**: Core file importing/referencing Web or API types
+- **Infrastructure depending on Web/API**: Infrastructure file importing Web or API types
+- **Cross-API dependencies**: Management API depending on Delivery API or vice versa
+
+### How to Check
+
+1. For each changed file, identify its layer
+2. Read the file's `using` statements (C#) or `import` statements (TS)
+3. Check if any imports reference a higher layer
+4. Also check if new parameters or return types come from higher layers
+
+---
+
+## 4. Flag Cross-Project Risks
+
+### High-Risk Patterns
+
+These changes have high ripple potential:
+
+- **Interface changes in Core** — all implementations in Infrastructure must be updated
+- **Notification type changes** — all handlers across the codebase are affected
+- **Base class changes** — all derived classes are affected
+- **Composer changes** — can affect DI container and runtime behavior globally
+- **Shared model/DTO changes** — can affect serialization, API contracts, and consumers
+
+### What to Report
+
+For each cross-project risk found, report:
+
+1. **What changed**: The specific symbol and how it changed
+2. **Who is affected**: List of consuming files/projects found via Grep
+3. **Risk level**: Whether the consumers will break (compile error), behave differently (runtime), or are unaffected
+4. **Recommendation**: Whether the PR should include updates to affected consumers
+
+---
+
+## 5. Performance Notes
+
+- Use `head_limit: 20` on all Grep searches to cap results
+- Only search for symbols that actually changed (not every symbol in the file)
+- For very common type names (e.g., `IScope`, `ILogger`), consider adding more context to the search pattern to reduce false positives
+- Skip impact analysis for test files — they don't have external consumers
+- Skip impact analysis for private/internal members — they can't have external consumers

.editorconfig

@@ -70,18 +70,6 @@ trim_trailing_whitespace = true
 [*.less]
 trim_trailing_whitespace = false
 
-##########################################
-# File Header (Uncomment to support file headers)
-# https://docs.microsoft.com/visualstudio/ide/reference/add-file-header
-##########################################
-
-# [*.{cs,csx,cake,vb,vbx}]
-file_header_template = Copyright (c) Umbraco.\nSee LICENSE for more details.
-
-# SA1636: File header copyright text should match
-# Justification: .editorconfig supports file headers. If this is changed to a value other than "none", a stylecop.json file will need to added to the project.
-# dotnet_diagnostic.SA1636.severity = none
-
 ##########################################
 # .NET Language Conventions
 # https://docs.microsoft.com/visualstudio/ide/editorconfig-language-conventions
@@ -136,6 +124,10 @@ dotnet_code_quality_unused_parameters = all:warning
 dotnet_style_operator_placement_when_wrapping = end_of_line
 # https://github.com/dotnet/roslyn/pull/40070
 dotnet_style_prefer_simplified_interpolation = true:warning
+# File header preferences
+file_header_template = Copyright (c) Umbraco.\nSee LICENSE for more details.
+dotnet_diagnostic.SA1633.severity = none # Suppressed until we decide to enforce it
+dotnet_diagnostic.SA1636.severity = none # Suppressed since we are using StyleCop
 
 # C# Code Style Settings
 # https://docs.microsoft.com/visualstudio/ide/editorconfig-language-conventions#c-code-style-settings

.env.example

@@ -0,0 +1,5 @@
+UMBRACO_CLIENT_ID=umbraco-back-office-mcp
+UMBRACO_CLIENT_SECRET=1234567890
+UMBRACO_BASE_URL=https://localhost:44339
+NODE_TLS_REJECT_UNAUTHORIZED=0
+UMBRACO_INCLUDE_TOOL_COLLECTIONS=data-type,document-type,document,media-type,media

.gitattributes

@@ -55,3 +55,9 @@
 *.sln text=auto eol=crlf merge=union
 
 *.gitattributes text=auto
+
+# Generated files - hidden by default in GitHub diffs
+src/Umbraco.Web.UI.Client/src/packages/core/backend-api/** linguist-generated
+src/Umbraco.Web.UI.Login/src/api/** linguist-generated
+templates/UmbracoExtension/Client/src/api/** linguist-generated
+src/Umbraco.Cms.Api.Management/OpenApi.json linguist-generated

.github/CONTRIBUTING.md

@@ -30,7 +30,7 @@ This guide describes each step to make your first contribution:
 
    Create a new branch based on `main` and name it after the issue you're fixing. For example: `v15/bugfix/18132-rte-tinymce-onchange-value-check`.
 
-   Please follow this format for branches: `v{major}/{feature|bugfix|task}/{issue}-{description}`.
+   Please follow this format for branches: `v{major}/{feature|bugfix|task|qa|improvement}/{issue}-{description}`.
 
    This is a development branch for the particular issue you're working on, in this case, a bug-fix for issue number `18132` that affects Umbraco v.15.
 

.github/ISSUE_TEMPLATE/01_bug_report.yml

@@ -7,7 +7,7 @@ body:
   id: "version"
   attributes:
     label: "Which Umbraco version are you using?"
-    description: "Please write the *exact* version, example: `10.1.0`. Use the help icon in the Umbraco backoffice to find the version you're using"
+    description: "Please write the *exact* version, example: `10.1.0`. Click the Umbraco logo in the top left corner of the backoffice to find the version you're using."
   validations:
     required: true
 - type: textarea

.github/copilot-instructions.md

@@ -1,218 +1 @@
-# Umbraco CMS Development Guide
-
-Always reference these instructions first and fallback to search or bash commands only when you encounter unexpected information that does not match the info here.
-
-## Working Effectively
-
-Bootstrap, build, and test the repository:
-
--   Install .NET SDK (version specified in global.json):
-    -   `curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --version $(jq -r '.sdk.version' global.json)`
-    -   `export PATH="/home/runner/.dotnet:$PATH"`
--   Install Node.js (version specified in src/Umbraco.Web.UI.Client/.nvmrc):
-    -   `curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.0/install.sh | bash`
-    -   `export NVM_DIR="$HOME/.nvm" && [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"`
-    -   `nvm install $(cat src/Umbraco.Web.UI.Client/.nvmrc) && nvm use $(cat src/Umbraco.Web.UI.Client/.nvmrc)`
--   Fix shallow clone issue (required for GitVersioning):
-    -   `git fetch --unshallow`
--   Restore packages:
-    -   `dotnet restore` -- takes 50 seconds. NEVER CANCEL. Set timeout to 90+ seconds.
--   Build the solution:
-    -   `dotnet build` -- takes 4.5 minutes. NEVER CANCEL. Set timeout to 10+ minutes.
--   Install and build frontend:
-    -   `cd src/Umbraco.Web.UI.Client`
-    -   `npm ci --no-fund --no-audit --prefer-offline` -- takes 11 seconds.
-    -   `npm run build:for:cms` -- takes 1.25 minutes. NEVER CANCEL. Set timeout to 5+ minutes.
--   Install and build Login
-    -   `cd src/Umbraco.Web.UI.Login`
-    -   `npm ci --no-fund --no-audit --prefer-offline`
-    -   `npm run build`
--   Run the application:
-    -   `cd src/Umbraco.Web.UI`
-    -   `dotnet run --no-build` -- Application runs on https://localhost:44339 and http://localhost:11000
-
-Check out [BUILD.md](./BUILD.md) for more detailed instructions.
-
-## Validation
-
--   ALWAYS run through at least one complete end-to-end scenario after making changes.
--   Build and unit tests must pass before committing changes.
--   Frontend build produces output in src/Umbraco.Web.UI.Client/dist-cms/ which gets copied to src/Umbraco.Web.UI/wwwroot/umbraco/backoffice/
--   Always run `dotnet build` and `npm run build:for:cms` before running the application to see your changes.
--   For login-only changes, you can run `npm run build` from src/Umbraco.Web.UI.Login and then `dotnet run --no-build` from src/Umbraco.Web.UI.
--   For frontend-only changes, you can run `npm run dev:server` from src/Umbraco.Web.UI.Client for hot reloading.
--   Frontend changes should be linted using `npm run lint:fix` which uses Eslint.
-
-## Testing
-
-### Unit Tests (.NET)
-
--   Location: tests/Umbraco.Tests.UnitTests/
--   Run: `dotnet test tests/Umbraco.Tests.UnitTests/Umbraco.Tests.UnitTests.csproj --configuration Release --verbosity minimal`
--   Duration: ~1 minute with 3,343 tests
--   NEVER CANCEL: Set timeout to 5+ minutes
-
-### Integration Tests (.NET)
-
--   Location: tests/Umbraco.Tests.Integration/
--   Run: `dotnet test tests/Umbraco.Tests.Integration/Umbraco.Tests.Integration.csproj --configuration Release --verbosity minimal`
--   NEVER CANCEL: Set timeout to 10+ minutes
-
-### Frontend Tests
-
--   Location: src/Umbraco.Web.UI.Client/
--   Run: `npm test` (requires `npx playwright install` first)
--   Frontend tests use Web Test Runner with Playwright
-
-### Acceptance Tests (E2E)
-
--   Location: tests/Umbraco.Tests.AcceptanceTest/
--   Requires running Umbraco application and configuration
--   See tests/Umbraco.Tests.AcceptanceTest/README.md for detailed setup (requires `npx playwright install` first)
-
-## Project Structure
-
-The solution contains 30 C# projects organized as follows:
-
-### Main Application Projects
-
--   **Umbraco.Web.UI**: Main web application project (startup project)
--   **Umbraco.Web.UI.Client**: TypeScript frontend (backoffice)
--   **Umbraco.Web.UI.Login**: Separate login screen frontend
--   **Umbraco.Core**: Core domain models and interfaces
--   **Umbraco.Infrastructure**: Data access and infrastructure
--   **Umbraco.Cms**: Main CMS package
-
-### API Projects
-
--   **Umbraco.Cms.Api.Management**: Management API
--   **Umbraco.Cms.Api.Delivery**: Content Delivery API
--   **Umbraco.Cms.Api.Common**: Shared API components
-
-### Persistence Projects
-
--   **Umbraco.Cms.Persistence.SqlServer**: SQL Server support
--   **Umbraco.Cms.Persistence.Sqlite**: SQLite support
--   **Umbraco.Cms.Persistence.EFCore**: Entity Framework Core abstractions
-
-### Test Projects
-
--   **Umbraco.Tests.UnitTests**: Unit tests
--   **Umbraco.Tests.Integration**: Integration tests
--   **Umbraco.Tests.AcceptanceTest**: End-to-end tests with Playwright
--   **Umbraco.Tests.Common**: Shared test utilities
-
-## Common Tasks
-
-### Running Umbraco in Different Modes
-
-**Production Mode (Standard Development)**
-Use this for backend development, testing full builds, or when you don't need hot reloading:
-
-1. Build frontend assets: `cd src/Umbraco.Web.UI.Client && npm run build:for:cms`
-2. Run backend: `cd src/Umbraco.Web.UI && dotnet run --no-build`
-3. Access backoffice: `https://localhost:44339/umbraco`
-4. Application uses compiled frontend from `wwwroot/umbraco/backoffice/`
-
-**Vite Dev Server Mode (Frontend Development with Hot Reload)**
-Use this for frontend-only development with hot module reloading:
-
-1. Configure backend for frontend development - Add to `src/Umbraco.Web.UI/appsettings.json` under `Umbraco:CMS:Security`:
-    ```json
-    "BackOfficeHost": "http://localhost:5173",
-    "AuthorizeCallbackPathName": "/oauth_complete",
-    "AuthorizeCallbackLogoutPathName": "/logout",
-    "AuthorizeCallbackErrorPathName": "/error",
-    "BackOfficeTokenCookie": {
-      "SameSite": "None"
-    }
-    ```
-2. Run backend: `cd src/Umbraco.Web.UI && dotnet run --no-build`
-3. Run frontend dev server: `cd src/Umbraco.Web.UI.Client && npm run dev:server`
-4. Access backoffice: `http://localhost:5173/` (no `/umbraco` prefix)
-5. Changes to TypeScript/Lit files hot reload automatically
-
-**Important:** Remove the `BackOfficeHost` configuration before committing or switching back to production mode.
-
-### Backend-Only Development
-
-For backend-only changes, disable frontend builds:
-
--   Comment out the target named "BuildStaticAssetsPreconditions" in src/Umbraco.Cms.StaticAssets.csproj:
-    ```
-    <!--<Target Name="BuildStaticAssetsPreconditions" BeforeTargets="AssignTargetPaths">
-      [...]
-    </Target>-->
-    ```
--   Remember to uncomment before committing
-
-### Building NuGet Packages
-
-To build custom NuGet packages for testing:
-
-```bash
-dotnet pack -c Release -o Build.Out
-dotnet nuget add source [Path to Build.Out folder] -n MyLocalFeed
-```
-
-### Regenerating Frontend API Types
-
-When changing Management API:
-
-```bash
-cd src/Umbraco.Web.UI.Client
-npm run generate:server-api-dev
-```
-
-Also update OpenApi.json from /umbraco/swagger/management/swagger.json
-
-## Database Setup
-
-Default configuration supports SQLite for development. For production-like testing:
-
--   Use SQL Server/LocalDb for better performance
--   Configure connection string in src/Umbraco.Web.UI/appsettings.json
-
-## Clean Up / Reset
-
-To reset development environment:
-
-```bash
-# Remove configuration and database
-rm src/Umbraco.Web.UI/appsettings.json
-rm -rf src/Umbraco.Web.UI/umbraco/Data
-
-# Full clean (removes all untracked files)
-git clean -xdf .
-```
-
-## Version Information
-
--   Target Framework: .NET (version specified in global.json)
--   Current Version: (specified in version.json)
--   Node.js Requirement: (specified in src/Umbraco.Web.UI.Client/.nvmrc)
--   npm Requirement: Latest compatible version
-
-## Known Issues
-
--   Build requires full git history (not shallow clone) due to GitVersioning
--   Some NuGet package security warnings are expected (SixLabors.ImageSharp vulnerabilities)
--   Frontend tests require Playwright browser installation: `npx playwright install`
--   Older Node.js versions may show engine compatibility warnings (check .nvmrc for current requirement)
-
-## Timing Expectations
-
-**NEVER CANCEL** these operations - they are expected to take time:
-
-| Operation               | Expected Time | Timeout Setting |
-| ----------------------- | ------------- | --------------- |
-| `dotnet restore`        | 50 seconds    | 90+ seconds     |
-| `dotnet build`          | 4.5 minutes   | 10+ minutes     |
-| `npm ci`                | 11 seconds    | 30+ seconds     |
-| `npm run build:for:cms` | 1.25 minutes  | 5+ minutes      |
-| `npm test`              | 2 minutes     | 5+ minutes      |
-| `npm run lint`          | 1 minute      | 5+ minutes      |
-| Unit tests              | 1 minute      | 5+ minutes      |
-| Integration tests       | Variable      | 10+ minutes     |
-
-Always wait for commands to complete rather than canceling and retrying.
+The full development guide for this repository lives in [CLAUDE.md](../CLAUDE.md). Please read that file for complete instructions on architecture, build steps, testing, branching conventions, and coding patterns.

.github/workflows/azure-backoffice.yml

@@ -4,9 +4,7 @@ on:
   push:
     branches:
       - main
-      - release/*
       - v*/dev
-      - v*/main
     paths:
       - src/Umbraco.Web.UI.Client/package.json
       - src/Umbraco.Web.UI.Client/package-lock.json
@@ -16,9 +14,7 @@ on:
     types: [opened, synchronize, reopened, closed]
     branches:
       - main
-      - release/*
       - v*/dev
-      - v*/main
   workflow_dispatch:
 
 jobs:
@@ -27,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     name: Build and Deploy Job
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           submodules: true
       - name: Build And Deploy

.github/workflows/azure-storybook.yml

@@ -5,7 +5,6 @@ on:
     branches:
       - main
       - v*/dev
-      - v*/main
     paths:
       - src/Umbraco.Web.UI.Client/package.json
       - src/Umbraco.Web.UI.Client/package-lock.json
@@ -16,7 +15,6 @@ on:
     branches:
       - main
       - v*/dev
-      - v*/main
   workflow_dispatch:
 
 env:
@@ -28,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     name: Build and Deploy Job
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Build And Deploy
         id: builddeploy
         uses: Azure/static-web-apps-deploy@v1

.github/workflows/claude-review.yml

@@ -0,0 +1,88 @@
+name: Claude PR Review
+
+on:
+  pull_request:
+    types: [opened, ready_for_review, reopened]
+  # NOTE: `pull_request_target` would let this workflow review fork PRs
+  # (with access to secrets), but the action currently fails during OIDC
+  # token exchange with "401 Unauthorized - Invalid OIDC token" on that
+  # event. PR #579 added `pull_request_target` routing to the action, but
+  # Anthropic's `/github-app-token-exchange` endpoint appears not to
+  # accept the token claims produced by that event. Re-enable once the
+  # upstream issue is resolved.
+  # See: https://github.com/anthropics/claude-code-action/issues/347
+  #      https://github.com/anthropics/claude-code-action/issues/621
+  # pull_request_target:
+  #   types: [opened, ready_for_review]
+
+permissions:
+  contents: read
+  pull-requests: write
+  id-token: write
+  actions: read
+
+jobs:
+  review:
+    # Skip fork PRs: secrets are not exposed on `pull_request` events from
+    # forks, so the action would fail with a red check. Remove this clause
+    # once upstream fork support lands (tracked in
+    # https://github.com/anthropics/claude-code-action/issues/939) and we
+    # can re-enable the `pull_request_target` trigger above.
+    if: >-
+      github.event.pull_request.draft == false
+      && github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 1
+
+      - uses: anthropics/claude-code-action@v1
+        with:
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY_03 }}
+
+          # Enable progress tracking
+          track_progress: true
+
+          # Debug (set to true to show full output in logs, false to hide it and only post comments on the PR)
+          show_full_output: false
+
+          additional_permissions: "actions: read"
+          claude_args: "--model claude-sonnet-4-6 --allowedTools 'Bash(gh:*),Bash(git:*)'"
+          prompt: |
+            You are reviewing pull request #${{ github.event.pull_request.number }}
+            in the Umbraco CMS repository.
+
+            Read and execute the review procedure defined in `.claude/skills/umb-review/SKILL.md`.
+
+            For each finding that references a specific file and line:
+            - Post an individual inline PR comment on that line.
+            - Format: **[Severity]** explanation, then suggestion.
+
+            For the overall summary (header, impact, verdict):
+            - Post ONE top-level PR comment.
+
+            Do NOT use sticky/updating comments — post new individual comments.
+
+            After reviewing, apply labels to the PR based on changed files:
+            - `area/frontend` — if files under `src/Umbraco.Web.UI.Client/` are changed
+            - `area/backend` — if .cs files outside the frontend client are changed
+            - `area/test` — if only test files are changed
+            - `category/api` — if Management API or Delivery API files are changed
+            - `category/breaking` — if breaking changes were detected in the review
+            - `category/localization` — if localization/language files are changed
+            - `category/test-automation` — if only test files are changed
+            - `category/refactor` — if the PR is pure refactoring with no new features
+            - `category/performance` — if performance-related changes are detected
+            - `category/ux` — if user-facing changes are detected
+            - `category/ui` — if changes to the UI layer are detected
+
+            Only apply labels you are confident about. Never remove existing labels.
+
+            Be friendly and constructive. This project values community contributions.
+            Frame feedback as suggestions where possible.
+            Reserve firm language for genuine Critical issues only.
+
+            Run fully autonomously. Do NOT ask questions.
+            Only review changed files. Do not flag pre-existing issues.
+            Do not suggest changes that would themselves introduce breaking changes.

.github/workflows/claude.yml

@@ -0,0 +1,91 @@
+name: Claude
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned, labeled]
+  pull_request_review:
+    types: [submitted]
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+  id-token: write
+
+jobs:
+  claude:
+    if: |
+      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
+      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude')) ||
+      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '@claude')) ||
+      (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 1
+
+      - uses: anthropics/claude-code-action@v1
+        with:
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY_03 }}
+          assignee_trigger: "claude"
+          label_trigger: "claude"
+          base_branch: "main"
+          additional_permissions: "actions: read"
+          claude_args: "--model claude-sonnet-4-6 --max-turns 50 --allowedTools 'Bash(gh:*),Bash(git:*),Bash(npm:*),Bash(dotnet:*)'"
+          prompt: |
+            You are an AI assistant for the Umbraco CMS repository, an open-source
+            .NET CMS that welcomes community contributions.
+
+            You were triggered on issue/PR #${{ github.event.issue.number || github.event.pull_request.number }}.
+
+            Read the user's message and do what they ask. The trigger phrase
+            `@claude` is stripped before you see the message, so common requests
+            will look like:
+
+            - `review` — Review PR #${{ github.event.issue.number || github.event.pull_request.number }}.
+              Use `gh pr diff ${{ github.event.issue.number || github.event.pull_request.number }}`
+              and `gh pr view ${{ github.event.issue.number || github.event.pull_request.number }}`
+              to read the changes. Do NOT use git diff or the umb-review skill.
+              Focus on bugs, breaking changes, and architectural concerns.
+              Post inline comments for specific issues and a brief summary.
+            - `help` or a general question — Answer based on the codebase.
+              Read CLAUDE.md files for project structure and conventions.
+            - `fix ...` — Implement the requested fix on a new branch.
+            - `label` — Apply appropriate labels to the PR or issue.
+
+            If the message is empty or just whitespace, treat it as `review`
+            when on a PR, or `help` when on an issue.
+
+            If none of these match, read the user's message carefully and respond
+            to what they actually asked for.
+
+            ## Labeling
+
+            When labeling PRs (based on changed files):
+            - `area/frontend`, `area/backend`, `area/test`
+            - `category/api`, `category/breaking`, `category/localization`
+            - `category/refactor`, `category/performance`, `category/ux`, `category/ui`
+            - `category/test-automation`
+
+            When labeling issues (based on content):
+            - `area/frontend`, `area/backend`, `area/test`
+            - `affected/v14` through `affected/v17`, `affected/backoffice`
+            - `category/api`, `category/localization`, `category/performance`
+            - `category/ux`, `category/ui`
+
+            Only apply labels you are confident about. Never remove existing labels.
+
+            ## Tone
+
+            Be friendly and constructive. Frame feedback as suggestions.
+            Reserve firm language for genuine critical issues only.
+
+            ## Constraints
+
+            - Run fully autonomously. Do NOT ask questions.
+            - Do not suggest changes that would introduce breaking changes.

.github/workflows/codeql-analysis.yml

@@ -51,7 +51,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # We use the setup-dotnet action to set up .NET Core, otherwise the CodeQL CLI will not work with preview versions.
       - name: Setup .NET from global.json

.github/workflows/issue-deduplication.yml

@@ -0,0 +1,84 @@
+name: Issue Deduplication
+
+on:
+  issues:
+    types: [ opened ]
+  workflow_dispatch:
+    inputs:
+      issue_number:
+        description: 'Issue number to analyze for duplicates'
+        required: true
+        type: number
+
+jobs:
+  deduplicate:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: read
+      issues: write
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 1
+
+      - name: Check for duplicate issues
+        uses: anthropics/claude-code-action@v1
+        with:
+          prompt: |
+            Analyze this new issue and check if it's a duplicate of existing issues in the repository.
+
+            Issue: #${{ github.event.issue.number || inputs.issue_number }}
+            Repository: ${{ github.repository }}
+
+            Your task:
+            1. Use mcp__github__get_issue to get details of the current issue (#${{ github.event.issue.number || inputs.issue_number }})
+            2. Search for similar existing issues using mcp__github__search_issues with relevant keywords from the issue title and body
+            3. Compare the new issue with existing ones to identify potential duplicates
+
+            Criteria for duplicates:
+            - Same bug or error being reported
+            - Same feature request (even if worded differently)
+            - Same question being asked
+            - Issues describing the same root problem
+
+            If you find duplicates:
+            - Add a comment on the new issue linking to the original issue(s)
+            - Apply the "duplicate" and "state/needs-investigation" labels to the new issue
+            - Be polite and explain why it's a duplicate
+            - Suggest the user follow the original issue for updates
+
+            If it's NOT a duplicate:
+            - Don't add any comments
+            - You may apply appropriate topic labels based on the issue content
+
+            Use these tools:
+            - mcp__github__get_issue: Get issue details
+            - mcp__github__search_issues: Search for similar issues
+            - mcp__github__list_issues: List recent issues if needed
+            - mcp__github__add_issue_comment: Add a comment if duplicate found
+            - mcp__github__update_issue: Add labels
+
+            Be thorough but efficient. Focus on finding true duplicates, not just similar issues.
+
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY_03 }}
+
+          # Issues are opened by community members without write access, so the
+          # default OIDC token exchange fails with "User does not have write
+          # access on this repository". Pass `github_token` explicitly and set
+          # `allowed_non_write_users` to bypass that check. Safe here because
+          # `permissions:` and `--allowedTools` below are tightly scoped to
+          # issue operations only.
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          allowed_non_write_users: "*"
+
+          # Surface full SDK output (including tool calls and permission denials)
+          # to diagnose why Claude sometimes only partially completes (e.g. labels
+          # an issue but skips the comment). Safe to leave on — no secrets in output.
+          show_full_output: true
+
+          claude_args: |
+            --model claude-haiku-4-5 --allowedTools "mcp__github__get_issue,mcp__github__search_issues,mcp__github__list_issues,mcp__github__add_issue_comment,mcp__github__update_issue,mcp__github__get_issue_comments"

.github/workflows/label-to-release-announcement.yml

@@ -12,6 +12,7 @@ permissions:
 
 jobs:
   reconcile:
+    if: github.repository == 'umbraco/Umbraco-CMS'
     runs-on: ubuntu-latest
     steps:
       - name: Reconcile release/* labels → discussions

.github/workflows/sonarcloud-analysis.yml

@@ -0,0 +1,99 @@
+name: "SonarQube Cloud - Analysis"
+
+# This workflow runs the full SonarCloud analysis with the SONAR_TOKEN secret.
+# It is skipped for fork PRs since secrets are not available in that context.
+
+on:
+  push:
+    branches:
+      - main
+      - "v*/dev"
+      - "v*/main"
+      - "release/*"
+  pull_request:
+    types: [opened, synchronize, reopened]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  SONAR_PROJECT_KEY: umbraco_Umbraco-CMS
+  SONAR_ORGANIZATION: umbraco
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  analyze:
+    name: Build and analyze
+    runs-on: ubuntu-latest
+    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.fork != true
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Setup .NET from global.json
+        uses: actions/setup-dotnet@v5
+
+      - name: Setup Java 21
+        uses: actions/setup-java@v5
+        with:
+          distribution: temurin
+          java-version: "21"
+
+      - name: Cache SonarQube packages
+        uses: actions/cache@v5
+        with:
+          path: ~/.sonar/cache
+          key: ${{ runner.os }}-sonar
+          restore-keys: ${{ runner.os }}-sonar
+
+      - name: Install tools
+        run: |
+          dotnet tool install --global dotnet-sonarscanner
+          dotnet tool install --global dotnet-coverage
+
+      - name: Load sonar params
+        run: echo "SONARQUBE_SCANNER_PARAMS=$(jq -c . .github/workflows/sonarcloud/sonar-params.json)" >> $GITHUB_ENV
+
+      - name: Begin analysis
+        env:
+          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+        run: |
+          dotnet-sonarscanner begin \
+            /k:"$SONAR_PROJECT_KEY" \
+            /o:"$SONAR_ORGANIZATION" \
+            /d:sonar.token="$SONAR_TOKEN" \
+            /d:sonar.scanner.skipJreProvisioning=true
+
+      - name: Restore
+        run: dotnet restore umbraco.sln
+
+      - name: Build solution
+        run: GITHUB_ENV=/dev/null dotnet build umbraco.sln --no-restore -clp:ErrorsOnly # prevent sonar MSBuild integration from writing malformed values to $GITHUB_ENV
+
+      - name: Run unit tests with coverage
+        id: tests
+        continue-on-error: true
+        run: |
+          dotnet-coverage collect \
+            "dotnet test tests/Umbraco.Tests.UnitTests/Umbraco.Tests.UnitTests.csproj --no-build" \
+            --output TestResults/coverage.xml \
+            --output-format xml
+
+      - name: Warn on test failure
+        if: steps.tests.outcome == 'failure'
+        run: |
+          if [ -f TestResults/coverage.xml ]; then
+            echo "::warning::Unit tests failed - SonarCloud analysis will proceed with the collected coverage data"
+          else
+            echo "::warning::Unit tests failed and no coverage data was collected"
+          fi
+
+      - name: End analysis
+        env:
+          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+        run: dotnet-sonarscanner end /d:sonar.token="$SONAR_TOKEN"

.github/workflows/sonarcloud/sonar-params.json

@@ -0,0 +1,7 @@
+{
+  "sonar.cs.vscoveragexml.reportsPaths": "TestResults/coverage.xml",
+  "sonar.inclusions": "src/**,templates/**,tools/**,tests/**,.github/**,build/**",
+  "sonar.exclusions": "**/bin/**,**/obj/**,**/node_modules/**,**/lang/*.ts,**/mocks/**,**/wwwroot/**,**/dist-cms/**,**/*.generated.cs,src/Umbraco.Web.UI/umbraco/**,src/Umbraco.Cms.Persistence.EFCore.*/Migrations/**,src/Umbraco.Web.UI.Client/src/packages/core/backend-api/**,**/.nuget/**",
+  "sonar.test.inclusions": "tests/**,**/*.test.ts,**/*.spec.ts",
+  "sonar.typescript.tsconfigPaths": "src/Umbraco.Web.UI.Client/tsconfig.json,src/Umbraco.Web.UI.Client/tsconfig.node.json,src/Umbraco.Web.UI.Login/tsconfig.json"
+}

.github/workflows/test-backoffice.yml

@@ -34,7 +34,7 @@ jobs:
       run:
         working-directory: src/Umbraco.Web.UI.Client
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Use Node.js
         uses: actions/setup-node@v4
         with:
@@ -57,7 +57,7 @@ jobs:
       run:
         working-directory: src/Umbraco.Web.UI.Client
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Use Node.js
         uses: actions/setup-node@v4
         with:

.gitignore

@@ -51,6 +51,12 @@ tools/docfx/
 /build/csharp-docs/api/
 /build/csharp-docs/_site/
 
+# Local config
+.claude/*
+!.claude/skills/
+!.claude/settings.json
+.env.local
+
 # Build
 /build.out/
 /build.tmp/
@@ -66,7 +72,8 @@ tools/docfx/
 /src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/assets
 /src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/js
 /src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/lib
-/src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/views
+/src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/views/*
+!/src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/views/errors
 /src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/login
 
 # Environment specific data
@@ -96,6 +103,10 @@ tools/docfx/
 /tests/Umbraco.Tests.Integration/Views/
 /tests/Umbraco.Tests.UnitTests/[Uu]mbraco/[Dd]ata/TEMP/
 /BenchmarkDotNet.Artifacts/
+playwright-report
+trace.zip
+/tests/Umbraco.Tests.AcceptanceTest/results
+/tests/Umbraco.Tests.AcceptanceTest/dist
 
 # Ignore auto-generated schema
 /src/Umbraco.Cms.Targets/tasks/
@@ -104,9 +115,12 @@ tools/docfx/
 /src/Umbraco.Web.UI/appsettings-schema.json
 /src/Umbraco.Web.UI/appsettings-schema.*.json
 /src/Umbraco.Web.UI/umbraco-package-schema.json
+/src/Umbraco.Web.UI.Client/umbraco-package-schema.json
 /tests/Umbraco.Tests.Integration/appsettings-schema.json
 /tests/Umbraco.Tests.Integration/appsettings-schema.*.json
 /tests/Umbraco.Tests.Integration/umbraco-package-schema.json
 /src/Umbraco.Cms/appsettings-schema.json
-playwright-report
-trace.zip
+.playwright-mcp/
+
+# SonarQube local analysis cache
+.sonarqube/

.globalconfig

@@ -48,7 +48,6 @@ dotnet_analyzer_diagnostic.category-StyleCop.CSharp.OrderingRules.severity = sug
 dotnet_analyzer_diagnostic.category-StyleCop.CSharp.MaintainabilityRules.severity = suggestion
 dotnet_analyzer_diagnostic.category-StyleCop.CSharp.LayoutRules.severity = suggestion
 
-dotnet_diagnostic.SA1636.severity = none # SA1636: File header copyright text should match
 dotnet_diagnostic.SA1101.severity = none # PrefixLocalCallsWithThis - stylecop appears to be ignoring dotnet_style_qualification_for_*
 dotnet_diagnostic.SA1309.severity = none # FieldNamesMustNotBeginWithUnderscore
 

.mcp.json

@@ -0,0 +1,14 @@
+{
+  "mcpServers": {
+    "umbraco-cms": {
+      "command": "npx",
+      "args": ["@umbraco-cms/mcp-dev@17"]
+    },
+    "playwright": {
+      "command": "npx",
+      "args": [
+        "@playwright/mcp@latest"
+      ]
+    }
+  }
+}

CLAUDE.md

@@ -46,7 +46,8 @@ Enterprise-grade CMS built on .NET 10.0. This repository contains 21 production
 - **ASP.NET Core** - Web framework
 - **Entity Framework Core** - Modern ORM
 - **OpenIddict** - OAuth 2.0/OpenID Connect authentication
-- **Swashbuckle** - OpenAPI/Swagger documentation
+- **Microsoft.AspNetCore.OpenApi** - OpenAPI document generation
+- **Swashbuckle.AspNetCore.SwaggerUI** - Swagger UI for API documentation
 - **Lucene.NET** - Full-text search via Examine
 - **ImageSharp** - Image processing
 
@@ -142,8 +143,33 @@ Web.UI → Web.Common → Infrastructure → Core
 ### Branching Strategy
 
 - **Main branch**: `main` (protected)
-- **Branch naming**:
-  - See `.github/CONTRIBUTING.md` for full guidelines
+- **Branch naming convention**: `v<version>/<type>/<description>`
+
+**Format**: `v{major-version}/{type}/{kebab-case-description}`
+
+**Version**: Read from `version.json` in the repository root. Use the major version number (e.g., `v17` for version 17.x.x).
+
+**Types**:
+| Type | Use Case |
+|------|----------|
+| `feature` | New feature being introduced to the product |
+| `bugfix` | Fix to an existing issue with the product |
+| `qa` | Adding or updating unit, integration, or end-to-end tests |
+| `improvement` | Update to something that already exists but isn't broken (UI finessing, refactoring) |
+| `task` | Update that doesn't directly impact product behavior (dependency updates, build pipeline) |
+
+**Description**: A short, kebab-case description (a few words). This should be prefixed with the GitHub issue number if the update is related to resolving a tracked issue.
+
+**Examples**:
+```
+v17/bugfix/12345-correct-display-of-pending-migrations
+v17/feature/add-webhook-support
+v17/improvement/optimize-content-cache
+v17/qa/add-media-service-tests
+v17/task/update-ef-core-dependency
+```
+
+See `.github/CONTRIBUTING.md` for full guidelines.
 
 ### Pull Request Process
 
@@ -173,7 +199,7 @@ Use the format: `Area: Description (closes #IssueID)`
 - Describe the change and its impact
 - Be specific, not vague (describe "a golden retriever" not just "a dog")
 
-**Issue Linking**: Add `(closes #IssueID)` to auto-close linked issues on merge.
+**Issue Linking**: Add `(closes #IssueID)` to the title for readability, AND include a closing keyword on its own line in the PR body (e.g., `Fixes #IssueID`) so GitHub actually auto-links and auto-closes the issue on merge. GitHub only parses closing keywords (`closes`, `fixes`, `resolves`) from the PR body or commit messages — the title suffix is cosmetic and does **not** trigger auto-close on its own.
 
 ### Commit Messages
 
@@ -202,9 +228,11 @@ Project ownership is distributed across teams. Check individual project director
 
 1. **Layered Architecture with Dependency Inversion**
    - Core defines contracts (interfaces)
-   - Infrastructure implements contracts
+   - Infrastructure implements contracts that need Infrastructure-owned machinery
    - Web/APIs consume implementations via DI
 
+   **Where service implementations live**: Services whose dependencies are satisfiable from Core interfaces alone (repositories, scope, config, other Core services) live in `Umbraco.Core/Services/` — this covers the majority of domain services (`MemberService`, `ContentService`, `MediaService`, `ContentTypeService`, `EntityService`, `AuditService`, `ExternalMemberService`, etc.). Service implementations only live in `Umbraco.Infrastructure/Services/Implement/` when they genuinely need Infrastructure concerns — Examine indexes (`ContentSearchService`, `MediaSearchService`, `IndexedEntitySearchService`), log files (`LogViewerRepository`), packaging internals (`PackagingService`), webhook firing (`WebhookFiringService`), distributed-job coordination (`DistributedJobService`). When adding a new service, default to Core and only move to Infrastructure if a concrete dependency forces it.
+
 2. **Interface-First Design**
    - All services defined as interfaces in Core
    - Enables testing, polymorphism, extensibility
@@ -234,20 +262,132 @@ Project ownership is distributed across teams. Check individual project director
 
 ---
 
-## 5. Project-Specific Notes
+## 5. Avoiding Breaking Changes
+
+No binary breaking changes are allowed within a major version. Three patterns are used:
+
+### 5.1 Obsolete Constructor + StaticServiceProvider
+
+When a public class needs new dependencies, obsolete the existing constructor and add a new one. The old constructor delegates to the new one, resolving missing deps via `StaticServiceProvider`.
+
+```csharp
+[Obsolete("Please use the constructor with all parameters. Scheduled for removal in Umbraco 19.")]
+public MyService(IDependencyA depA)
+    : this(
+        depA,
+        StaticServiceProvider.Instance.GetRequiredService<IDependencyB>())
+{
+}
+
+public MyService(IDependencyA depA, IDependencyB depB)
+{
+    _depA = depA;
+    _depB = depB;
+}
+```
+
+**Examples**:
+- `ContentCollectionPresentationFactory` - added `FlagProviderCollection`
+- `CacheInstructionService` - added `ILastSyncedManager`, `IRepositoryCacheVersionService`
+- `DocumentPresentationFactory` - added `FlagProviderCollection`
+
+**Rules**:
+- Old constructor marked `[Obsolete("... Scheduled for removal in Umbraco {current-major+2}.")]`
+- Old constructor calls new constructor via `: this(...)`
+- Uses `StaticServiceProvider.Instance.GetRequiredService<T>()` for new params only
+- DI registration must use the NEW constructor (old is for external consumers only)
+
+### 5.2 Obsolete Method + New Overload
+
+When a public method signature needs to change, add the new method/overload and obsolete the old. The obsolete method should call the new one with suitable defaults.
+
+```csharp
+[Obsolete("Use the overload taking all parameters. Scheduled for removal in Umbraco 19.")]
+public void DoThing(string name)
+    => DoThing(name, extraParam: null);
+
+public void DoThing(string name, string? extraParam)
+{
+    // Real implementation here
+}
+```
+
+**Rules**:
+- Old method marked `[Obsolete]` with removal schedule
+- DRY: old method calls new method, providing defaults for new parameters
+- All internal callers must be updated to use the new method
+- No callers should remain on the obsolete method within the codebase
+
+### 5.3 Default Interface Implementation
+
+When adding methods to a public interface, provide a default implementation so existing external implementations don't break.
+
+```csharp
+public interface IMyService
+{
+    // Existing method
+    void ExistingMethod();
+
+    // New method with default implementation
+    void NewMethod(string param)
+        => ExistingMethod(); // delegate to existing if possible
+}
+```
+
+**Strategies for the default** (in order of preference):
+1. **Use existing interface methods** to satisfy the contract (even if not optimal)
+2. **Return a sensible default** like empty collection, null, etc.
+3. **Throw `NotImplementedException`** if no reasonable default exists
+
+**Example**: `IContentService.SaveBlueprint` - new overload with `IContent? createdFromContent` has a default impl that calls the old method (ignoring the new param).
+
+**Example**: `IDocumentPresentationFactory.CreateCulturePublishScheduleModels` - full default implementation with logic, uses `StaticServiceProvider` for dependency resolution within the interface.
+
+**Rules**:
+- Add `// TODO (V{next-major}): Remove the default implementation when {obsolete method} is removed.` comment
+- Default impl should be functionally correct even if not optimal
+- If using `StaticServiceProvider` in a default impl, note this is temporary
+
+### 5.4 General Rules
+
+- **Removal policy**: Obsoleted members must remain for at least one full major version before removal. If obsoleted in version N, the earliest removal is version N+2. For example, something obsoleted in v17 is scheduled for removal in v19 (giving the whole of v18 as a deprecation period).
+- All `[Obsolete]` attributes must include **"Scheduled for removal in Umbraco {current+2}"**
+- Read `version.json` to determine the current major version
+- Suppress `CS0618` warnings where obsolete members must call each other:
+  ```csharp
+  #pragma warning disable CS0618 // Type or member is obsolete
+      => OldMethod(param);
+  #pragma warning restore CS0618 // Type or member is obsolete
+  ```
+- Update ALL internal callers to use the new API - no internal code should use obsolete members
+
+---
+
+## 6. Project-Specific Notes
 
 ### Centralized Package Management
 
-**All NuGet package versions** are centralized in `Directory.Packages.props`. Individual projects do NOT specify versions.
+**NuGet package versions** are centralized in `Directory.Packages.props`. There are two `Directory.Packages.props` files in the source tree, with multi-level merging enabled so the test file inherits from the root:
+
+| File | Scope |
+|------|-------|
+| `Directory.Packages.props` (root) | Production source code packages — referenced by all `src/**` projects |
+| `tests/Directory.Packages.props` | Test-only packages (NUnit, Moq, Bogus, BenchmarkDotNet, etc.) — adds entries on top of the inherited root file |
+
+When updating dependencies, decide which file the package belongs in:
+- A package used only by test projects → `tests/Directory.Packages.props`
+- A package used by any production project (or by both production and tests) → root `Directory.Packages.props`
 
 ```xml
 <!-- Individual projects reference WITHOUT version -->
-<PackageReference Include="Swashbuckle.AspNetCore" />
+<PackageReference Include="Microsoft.AspNetCore.OpenApi" />
 
 <!-- Versions defined in Directory.Packages.props -->
-<PackageVersion Include="Swashbuckle.AspNetCore" Version="6.5.0" />
+<PackageVersion Include="Microsoft.AspNetCore.OpenApi" Version="10.0.0" />
 ```
 
+**Opt-out**: `src/Umbraco.Web.UI/Umbraco.Web.UI.csproj` sets `<ManagePackageVersionsCentrally>false</ManagePackageVersionsCentrally>` and specifies versions inline (for `Microsoft.EntityFrameworkCore.Design`, `Microsoft.Build.Tasks.Core`, `Microsoft.ICU.ICU4C.Runtime`, etc.). Update those versions directly in that csproj when bumping. Two further `Directory.Packages.props` files exist under `templates/` for the project/extension templates and have their own version sets — keep `Microsoft.AspNetCore.OpenApi` aligned between the root file and `templates/UmbracoExtension/`.
+
 ### Build Configuration
 
 - `Directory.Build.props` - Shared properties (target framework, company, copyright)
@@ -267,13 +407,18 @@ The repository contains BOTH (actively supported):
 All APIs use **OpenIddict** (OAuth 2.0/OpenID Connect):
 - Reference tokens (not JWT) for better security
 - **Secure cookie-based token storage** (v17+) - tokens stored in HTTP-only cookies with `__Host-` prefix
-- Tokens are redacted from client-side responses and passed via secure cookies only
+- Tokens are redacted from client-side responses and passed via secure cookies only (`[redacted]` placeholder)
 - ASP.NET Core Data Protection for token encryption
 - Configured in `Umbraco.Cms.Api.Common`
 - API requests must include credentials (`credentials: include` for fetch)
 
 **Load Balancing Requirement**: All servers must share the same Data Protection key ring.
 
+**Frontend auth pitfalls** — see `src/Umbraco.Web.UI.Client/docs/edge-cases.md` (Auth & Cross-tab section) and `docs/security.md`. Key points:
+- Never call `validateToken()` per API request — it revokes the previous reference token (ID2019 errors)
+- `window.opener` is set for ANY `window.open()` target, not only OAuth popups — scope guards to the pathname too
+- BroadcastChannel does not deliver messages to the sender's own tab
+
 ### Content Caching Strategy
 
 **HybridCache** (`Umbraco.PublishedCache.HybridCache`):
@@ -286,7 +431,30 @@ All APIs use **OpenIddict** (OAuth 2.0/OpenID Connect):
 APIs use `Asp.Versioning.Mvc`:
 - Management API: `/umbraco/management/api/v{version}/*`
 - Delivery API: `/umbraco/delivery/api/v{version}/*`
-- OpenAPI/Swagger docs per version
+- OpenAPI docs: `/umbraco/openapi/management.json`, `/umbraco/openapi/delivery.json`
+- Swagger UI: `/umbraco/openapi/`
+
+### Updating `OpenApi.json` (Management API)
+
+When a PR changes Management API controllers or models, the `OpenApi.json` file in the Management API project must be updated:
+
+1. Run the Umbraco instance locally
+2. Open Swagger UI and navigate to the swagger.json link (e.g. `https://localhost:44339/umbraco/swagger/management/swagger.json`)
+3. Copy the full JSON content and paste it into `src/Umbraco.Cms.Api.Management/OpenApi.json`
+
+**Important**: Commit only the substantive changes — not IDE-applied formatting (whitespace, reordering, etc.). Extraneous formatting diffs make PRs harder to review and merge-ups more error-prone.
+
+### Backoffice npm Package
+
+The backoffice is published to npm as `@umbraco-cms/backoffice`. Runtime dependencies are provided via importmap; npm peerDependencies provide types only. For full details on dependency hoisting, version range logic, and plugin development, see `/src/Umbraco.Web.UI.Client/CLAUDE.md` → "npm Package Publishing".
+
+### SQL Server 2100-parameter limit
+
+Any `WHERE IN (@0, @1, ...)` built from a runtime-sized collection risks hitting SQL Server's 2100-parameter ceiling and throwing `SqlException` 8003 in production.
+
+Batch with `IEnumerable<T>.InGroupsOf(Constants.Sql.MaxParameterCount)` or `Database.FetchByGroups(...)` whenever the collection size is driven by user data — not just when it currently fits. Watch for products of two scaling dimensions (documents × languages, properties × versions) and config-tunable batch sizes whose defaults are safe but ceilings aren't.
+
+Full guidance, safe patterns and decision rule: see `/src/Umbraco.Infrastructure/CLAUDE.md` → "Avoiding the SQL Server 2100-parameter limit".
 
 ### Known Limitations
 
@@ -296,6 +464,104 @@ APIs use `Asp.Versioning.Mvc`:
 
 ---
 
+## 7. CI/CD — Claude AI Assistant
+
+Two GitHub Actions workflows powered by `anthropics/claude-code-action@v1`. Advisory only — does not block merging.
+
+### Workflows
+
+| File | Trigger | Purpose |
+|------|---------|---------|
+| `claude-review.yml` | `pull_request: [opened, ready_for_review]` | Auto-review every non-draft PR using the `umb-review` skill |
+| `claude.yml` | `@claude` comments, issue assign/label | Interactive assistant for PRs and issues |
+
+### Auto-Review (`claude-review.yml`)
+
+Runs the full `.claude/skills/umb-review/SKILL.md` procedure on every newly opened or un-drafted PR. Produces inline comments per finding and one summary comment with a verdict. Skips draft PRs. No turn limit.
+
+### Interactive (`claude.yml`)
+
+Responds to `@claude` mentions on PRs and issues. The trigger phrase is stripped before Claude sees the message, so:
+
+- `@claude review` → light review using `gh pr diff` (not the umb-review skill)
+- `@claude fix ...` → implements a fix on a new branch
+- `@claude help` → answers questions about the codebase
+- `@claude label` → applies labels
+- `@claude` (empty) → defaults to `review` on PRs, `help` on issues
+
+Also triggers on issue assignment to `claude` or adding the `claude` label. Gated: only runs when `@claude` appears in the comment/issue body. Max 25 turns.
+
+**Allowed Bash tools**: `gh`, `git`, `npm`, `dotnet` (interactive only; auto-review allows `gh` and `git`).
+
+### Labels
+
+Both workflows apply labels based on content:
+
+**On PRs** (based on changed files):
+
+| Label | Condition |
+|-------|-----------|
+| `area/frontend` | Files under `src/Umbraco.Web.UI.Client/` |
+| `area/backend` | `.cs` files outside the frontend client |
+| `area/test` | Only test files changed |
+| `category/api` | Management or Delivery API files |
+| `category/breaking` | Breaking changes detected |
+| `category/localization` | Localization/language files |
+| `category/test-automation` | Only test files changed |
+| `category/refactor` | Pure refactoring, no new features |
+| `category/performance` | Performance-related changes |
+| `category/ux` | User-facing changes |
+| `category/ui` | UI layer changes |
+
+**On Issues** (based on content): same `area/*` and `category/*` labels, plus `affected/v14` through `affected/v17` and `affected/backoffice`.
+
+Labels are only added, never removed. Claude applies only labels it is confident about.
+
+### Key Implementation Notes
+
+- **Checkout required** — the action internally runs `git fetch origin main` for trusted file restoration. Without `actions/checkout`, it fails with `fatal: not a git repository`.
+- **`id-token: write` permission** — required for OIDC token exchange with the Claude GitHub App.
+- **Trigger phrase stripping** — the action strips `@claude` from comments before passing to Claude. Prompts must reference commands without the prefix (e.g., `review` not `@claude review`).
+- **PR number injection** — the interactive workflow injects the PR/issue number into the prompt via `${{ github.event.issue.number }}` since Claude can't discover it from `gh pr view` when checked out on `main`.
+
+---
+
+## 8. Code Comment Policy
+
+**Default to no comment.** Applies to all code in this repository — C#, TypeScript, Razor, build scripts. Well-named identifiers and small functions are the primary form of self-documentation; comments are a fallback for the rare cases where the code itself cannot carry the meaning.
+
+### When NOT to comment
+
+- **Don't restate what the code does.** A line calling `resetState()` does not need `// Reset state`. A method named `validateInput` does not need `// Validate input`.
+- **Don't narrate a sequence of calls.** If three lines run in order, the order is in the code — don't paraphrase it above.
+- **Don't reference the current task, fix, callers, or PR.** No `// Fix for X`, `// Used by Y`, `// Added for the Z flow`, `// See PR #1234`. That belongs in commit messages and PR descriptions; in source it rots as the codebase evolves.
+
+### When a comment IS justified
+
+Write a comment only when **removing it would leave a future reader confused**. Concretely:
+
+- **A non-obvious WHY.** A hidden constraint, business rule, or ordering requirement that is not visible from the code.
+- **A workaround for a specific bug or platform quirk.** Link the issue (`(#21996)`, `https://...`) so the comment can be deleted once the upstream fix lands.
+- **A subtle invariant** that the type system or method names do not enforce.
+- **An edge case the code intentionally handles** that would surprise a reader (e.g. "must run before X because Y").
+- **API documentation** — XML doc comments on C# members, JSDoc on exported TypeScript symbols. Required for the public contract; still keep them concise.
+
+### TODOs
+
+Allowed, but cheap to write and cheaper to leave behind. Keep them short and trackable: `// TODO (V19): remove once obsolete overload is gone` or `// TODO: pagination [NL]`. A TODO should have an author or a version trigger.
+
+---
+
+## 9. Testing Practices
+
+### Tests for a bug fix must fail before the fix
+
+Verify any test you add for a bug fix actually catches the bug: either write the failing test first (TDD), or temporarily revert the production change and confirm the test fails before re-applying. A test that passes both ways proves nothing. Watch for coincidental passes — default seed/sort orders can make a buggy path produce the right answer for the test's specific inputs; construct inputs so the broken and fixed behaviours give visibly different results.
+
+For integration tests that exercise caching or cache refreshers, see `tests/Umbraco.Tests.Integration/CLAUDE.md` — the harness disables caching by default, which can produce false greens.
+
+---
+
 ## Quick Reference
 
 ### Essential Commands
@@ -317,6 +583,16 @@ dotnet format
 dotnet pack -c Release
 ```
 
+### Integration Test Database Configuration
+
+Integration tests are configured in `tests/Umbraco.Tests.Integration/appsettings.Tests.json`.
+
+The `Tests:Database:DatabaseType` setting controls which database is used:
+- `"SQLite"` (default) - No external dependencies
+- `"LocalDb"` - Uses SQL Server LocalDB, required for SQL Server-specific tests (e.g., page-level locking, `sys.dm_tran_locks`)
+
+SQL Server-specific tests use `BaseTestDatabase.IsSqlite()` to skip when running on SQLite.
+
 ### Key Projects
 
 | Project | Type | Description |
@@ -342,6 +618,9 @@ dotnet pack -c Release
 For detailed information about individual projects, see their CLAUDE.md files:
 - **Core Architecture**: `/src/Umbraco.Core/CLAUDE.md` - Service contracts, notification patterns
 - **API Infrastructure**: `/src/Umbraco.Cms.Api.Common/CLAUDE.md` - OpenAPI, authentication, serialization
+- **Backoffice Frontend**: `/src/Umbraco.Web.UI.Client/CLAUDE.md` - Lit web components, extension system, auth client
+
+**Important**: When working on backoffice client code (anything under `src/Umbraco.Web.UI.Client/`), read `/src/Umbraco.Web.UI.Client/CLAUDE.md` first. It contains action-specific checklists (deprecation, testing, security, etc.) that are not duplicated here.
 
 ### Getting Help
 

Directory.Build.props

@@ -41,7 +41,7 @@
   <PropertyGroup>
     <GenerateCompatibilitySuppressionFile>false</GenerateCompatibilitySuppressionFile>
     <EnablePackageValidation>true</EnablePackageValidation>
-    <PackageValidationBaselineVersion>17.0.0</PackageValidationBaselineVersion>
+    <PackageValidationBaselineVersion>18.0.0</PackageValidationBaselineVersion>
     <EnableStrictModeForCompatibleFrameworksInPackage>true</EnableStrictModeForCompatibleFrameworksInPackage>
     <EnableStrictModeForCompatibleTfms>true</EnableStrictModeForCompatibleTfms>
   </PropertyGroup>
@@ -64,4 +64,14 @@
       </_ProjectReferencesWithVersions>
     </ItemGroup>
   </Target>
+
+  <!-- Workaround for https://github.com/umbraco/Umbraco-CMS/issues/23018
+       Due to the amount of XML documentation in this solution, the OpenAPI XML documentation source generator produces
+       too many lines of code causing a StackOverflowException when running on IIS. For that reason we disable the analyzer.
+       See https://learn.microsoft.com/en-us/aspnet/core/fundamentals/openapi/openapi-comments?view=aspnetcore-10.0#disabling-xml-documentation-support -->
+  <Target Name="DisableCompileTimeOpenApiXmlGenerator" BeforeTargets="CoreCompile" Condition="'$(IsPackable)' != 'false' or '$(IsTestProject)' == 'true'">
+    <ItemGroup>
+      <Analyzer Remove="@(Analyzer)" Condition="'%(Filename)' == 'Microsoft.AspNetCore.OpenApi.SourceGenerators'" />
+    </ItemGroup>
+  </Target>
 </Project>

Directory.Packages.props

@@ -2,81 +2,97 @@
 <Project>
   <PropertyGroup>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+    <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
   </PropertyGroup>
   <!-- Global packages (private, build-time packages for all projects) -->
   <ItemGroup>
     <GlobalPackageReference Include="Nerdbank.GitVersioning" Version="3.9.50" />
     <GlobalPackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.556" />
-    <GlobalPackageReference Include="Umbraco.Code" Version="2.4.0" />
+    <!-- TODO (V18): Bump Umbraco.Code to 3.0.0 stable before release of 18.0.0 -->
+    <GlobalPackageReference Include="Umbraco.Code" Version="3.0.0-beta" />
     <GlobalPackageReference Include="Umbraco.GitVersioning.Extensions" Version="0.2.0" />
   </ItemGroup>
   <!-- Microsoft packages -->
   <ItemGroup>
-    <PackageVersion Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.14.0" />
-    <PackageVersion Include="Microsoft.Data.Sqlite" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.EntityFrameworkCore.Sqlite" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Caching.Abstractions" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Caching.Memory" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Configuration.Json" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.FileProviders.Embedded" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.FileProviders.Physical" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Http" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Identity.Core" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Identity.Stores" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Logging" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Options" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Options.DataAnnotations" Version="10.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Caching.Hybrid" Version="10.0.0" />
-    <PackageVersion Include="System.Linq.Async" Version="7.0.0" />
+    <PackageVersion Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="10.0.7" />
+    <!-- When updating this version, also update templates/UmbracoExtension/Umbraco.Extension.csproj -->
+    <PackageVersion Include="Microsoft.AspNetCore.OpenApi" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="5.3.0" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="5.3.0" />
+    <PackageVersion Include="Microsoft.Data.Sqlite" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.EntityFrameworkCore.Sqlite" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Caching.Abstractions" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Caching.Memory" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Configuration.Json" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.FileProviders.Embedded" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.FileProviders.Physical" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Http" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Identity.Core" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Identity.Stores" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Logging" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Options" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Options.DataAnnotations" Version="10.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Caching.Hybrid" Version="10.5.0" />
+    <PackageVersion Include="System.Linq.Async" Version="7.0.1" />
   </ItemGroup>
   <!-- Umbraco packages -->
   <ItemGroup>
-    <PackageVersion Include="Umbraco.JsonSchema.Extensions" Version="0.3.0" />
+    <PackageVersion Include="Umbraco.JsonSchema.Extensions" Version="0.4.0" />
   </ItemGroup>
   <!-- Third-party packages -->
   <ItemGroup>
-    <PackageVersion Include="Asp.Versioning.Mvc" Version="8.1.0" />
-    <PackageVersion Include="Asp.Versioning.Mvc.ApiExplorer" Version="8.1.0" />
+    <PackageVersion Include="Asp.Versioning.Mvc" Version="10.0.0" />
+    <PackageVersion Include="Asp.Versioning.Mvc.ApiExplorer" Version="10.0.0" />
     <PackageVersion Include="Dazinator.Extensions.FileProviders" Version="2.0.0" />
-    <PackageVersion Include="Examine" Version="3.7.1" />
-    <PackageVersion Include="Examine.Core" Version="3.7.1" />
+    <PackageVersion Include="Examine" Version="3.8.0" />
+    <PackageVersion Include="Examine.Core" Version="3.8.0" />
     <PackageVersion Include="HtmlAgilityPack" Version="1.12.4" />
     <PackageVersion Include="JsonPatch.Net" Version="3.3.0" />
     <PackageVersion Include="K4os.Compression.LZ4" Version="1.3.8" />
-    <PackageVersion Include="MailKit" Version="4.14.1" />
+    <PackageVersion Include="MailKit" Version="4.16.0" />
+    <PackageVersion Include="Markdig" Version="1.1.3" />
     <PackageVersion Include="Markdown" Version="2.2.1" />
-    <PackageVersion Include="MessagePack" Version="3.1.4" />
+    <PackageVersion Include="MessagePack" Version="3.1.7" />
     <PackageVersion Include="MiniProfiler.AspNetCore.Mvc" Version="4.5.4" />
     <PackageVersion Include="MiniProfiler.Shared" Version="4.5.4" />
     <PackageVersion Include="ncrontab" Version="3.4.0" />
-    <PackageVersion Include="NPoco" Version="6.1.0" />
-    <PackageVersion Include="NPoco.SqlServer" Version="6.1.0" />
-    <PackageVersion Include="OpenIddict.Abstractions" Version="7.2.0" />
-    <PackageVersion Include="OpenIddict.AspNetCore" Version="7.2.0" />
-    <PackageVersion Include="OpenIddict.EntityFrameworkCore" Version="7.2.0" />
-    <PackageVersion Include="Serilog" Version="4.3.0" />
-    <PackageVersion Include="Serilog.AspNetCore" Version="9.0.0" />
+    <PackageVersion Include="NPoco" Version="6.2.0" />
+    <PackageVersion Include="NPoco.SqlServer" Version="6.2.0" />
+    <PackageVersion Include="OpenIddict.Abstractions" Version="7.5.0" />
+    <PackageVersion Include="OpenIddict.AspNetCore" Version="7.5.0" />
+    <PackageVersion Include="OpenIddict.EntityFrameworkCore" Version="7.5.0" />
+    <PackageVersion Include="Serilog" Version="4.3.1" />
+    <PackageVersion Include="Serilog.AspNetCore" Version="10.0.0" />
     <PackageVersion Include="Serilog.Enrichers.Process" Version="3.0.0" />
     <PackageVersion Include="Serilog.Enrichers.Thread" Version="4.0.0" />
     <PackageVersion Include="Serilog.Expressions" Version="5.0.0" />
-    <PackageVersion Include="Serilog.Extensions.Hosting" Version="9.0.0" />
+    <PackageVersion Include="Serilog.Extensions.Hosting" Version="10.0.0" />
     <PackageVersion Include="Serilog.Formatting.Compact" Version="3.0.0" />
     <PackageVersion Include="Serilog.Formatting.Compact.Reader" Version="4.0.0" />
-    <PackageVersion Include="Serilog.Settings.Configuration" Version="9.0.0" />
+    <PackageVersion Include="Serilog.Settings.Configuration" Version="10.0.0" />
     <PackageVersion Include="Serilog.Sinks.Async" Version="2.1.0" />
     <PackageVersion Include="Serilog.Sinks.File" Version="7.0.0" />
     <PackageVersion Include="Serilog.Sinks.Map" Version="2.0.0" />
     <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.12" />
     <PackageVersion Include="SixLabors.ImageSharp.Web" Version="3.2.0" />
-    <PackageVersion Include="Swashbuckle.AspNetCore" Version="10.0.1" />
+    <PackageVersion Include="Swashbuckle.AspNetCore.SwaggerUI" Version="10.1.7" />
   </ItemGroup>
   <!-- Transitive pinned versions (only required because our direct dependencies have vulnerable versions of transitive dependencies) -->
   <ItemGroup>
+    <!-- Dazinator.Extensions.FileProviders references vulnerable versions of the following: -->
+    <!-- TODO (V18): Remove these pinned dependencies when the Dazinator.Extensions.FileProviders dependency is removed. -->
+    <PackageVersion Include="System.Net.Http" Version="4.3.4" />
+    <PackageVersion Include="System.Private.Uri" Version="4.3.2" />
+    <!-- Markdown references vulnerable version of the following: -->
+    <!-- TODO (V19): Remove these pinned dependencies when the Markdown dependency is removed. -->
+    <PackageVersion Include="System.Text.RegularExpressions" Version="4.3.1" />
+    <!-- Examine (via Microsoft.AspNetCore.DataProtection 8.0.4) references a vulnerable version of the following: -->
+    <!-- TODO: Remove this pinned dependency when Examine updates its Microsoft.AspNetCore.DataProtection reference. -->
+    <PackageVersion Include="System.Security.Cryptography.Xml" Version="10.0.7" />
   </ItemGroup>
 </Project>

MCP.md

@@ -0,0 +1,144 @@
+# MCP (Model Context Protocol) Setup
+
+This repository includes configuration for [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) servers, enabling AI tooling integration for Umbraco CMS development workflows.
+
+## Overview
+
+MCP allows AI assistants (like Claude) to interact with external tools and services. This repository configures two MCP servers:
+
+| Server | Purpose | Package |
+|--------|---------|---------|
+| **umbraco-cms** | Manage Umbraco content types, documents, and media | `@umbraco-cms/mcp-dev@17` |
+| **playwright** | Browser automation for testing and debugging | `@playwright/mcp@latest` |
+
+## Quick Start
+
+### 1. Start Umbraco Locally
+
+Ensure your local Umbraco instance is running at `https://localhost:44339` (or update the URL in your `.env.local`).
+
+### 2. Configure Environment Variables
+
+Copy the example environment file and customize it:
+
+```bash
+cp .env.example .env.local
+```
+
+Edit `.env.local` with your local settings:
+
+```env
+UMBRACO_CLIENT_ID=umbraco-back-office-mcp
+UMBRACO_CLIENT_SECRET=<your-client-secret>
+UMBRACO_BASE_URL=https://localhost:44339
+NODE_TLS_REJECT_UNAUTHORIZED=0
+UMBRACO_INCLUDE_TOOL_COLLECTIONS=data-type,document-type,document,media-type,media
+```
+
+### 3. Configure the OAuth Client in Umbraco
+
+Create an OAuth client in your Umbraco instance with:
+- **Client ID**: `umbraco-back-office-mcp`
+- **Client Secret**: The value you set in `.env.local`
+- **Grant Type**: Client Credentials
+
+## Environment Variables Reference
+
+| Variable | Description | Example |
+|----------|-------------|---------|
+| `UMBRACO_CLIENT_ID` | OAuth client ID configured in Umbraco | `umbraco-back-office-mcp` |
+| `UMBRACO_CLIENT_SECRET` | OAuth client secret (keep secure!) | `your-secure-secret` |
+| `UMBRACO_BASE_URL` | URL of your local Umbraco instance | `https://localhost:44339` |
+| `NODE_TLS_REJECT_UNAUTHORIZED` | Set to `0` for self-signed certificates (local dev only) | `0` |
+| `UMBRACO_INCLUDE_TOOL_COLLECTIONS` | Comma-separated list of tool collections to enable | `data-type,document-type,document` |
+
+### Tool Collections
+
+The `UMBRACO_INCLUDE_TOOL_COLLECTIONS` variable controls which Umbraco MCP tools are available:
+
+- `data-type` - Manage data types (property editors)
+- `document-type` - Manage document types (content types)
+- `document` - Manage content/documents
+- `media-type` - Manage media types
+- `media` - Manage media items
+
+## Security Considerations
+
+> **Warning**: This configuration is for **local development only**.
+
+### Self-Signed Certificates
+
+`NODE_TLS_REJECT_UNAUTHORIZED=0` disables SSL certificate validation. This is necessary for self-signed certificates in local development but:
+
+- **Never use in production**
+- Affects all HTTPS connections made by Node.js processes
+- Consider trusting your local development certificate instead
+
+### Client Secrets
+
+- Never commit real secrets to source control
+- The `.env.local` file is gitignored for this reason
+- Use strong, unique secrets even in development
+- The example value `1234567890` in `.env.example` is a placeholder only
+
+## File Structure
+
+```
+Umbraco-CMS/
+├── .mcp.json              # MCP server configuration
+├── .env.example           # Example environment variables (committed)
+├── .env.local             # Your local environment variables (gitignored)
+├── .claude/
+│   ├── settings.json      # Shared Claude AI permissions (committed)
+│   └── settings.local.json # Local Claude overrides (gitignored)
+├── .gitignore             # Ignores .env.local and settings.local.json
+└── MCP.md                 # This documentation (you are here)
+```
+
+## Claude AI Permissions
+
+The `.claude/settings.json` file configures which MCP tools Claude can use automatically without prompting. This is shared across the team for consistent developer experience.
+
+### Customizing Permissions Locally
+
+Create `.claude/settings.local.json` to override permissions for your environment:
+
+```json
+{
+  "permissions": {
+    "allow": [
+      "mcp__umbraco__get-all-document-types"
+    ]
+  }
+}
+```
+
+## Troubleshooting
+
+### "Connection refused" errors
+
+- Ensure Umbraco is running at the configured `UMBRACO_BASE_URL`
+- Check that the port matches your local setup
+
+### "Unauthorized" errors
+
+- Verify the OAuth client is configured in Umbraco
+- Check that `UMBRACO_CLIENT_ID` and `UMBRACO_CLIENT_SECRET` match
+- Ensure the client has appropriate permissions
+
+### "Certificate" errors
+
+- For local development, set `NODE_TLS_REJECT_UNAUTHORIZED=0` in `.env.local`
+- Alternatively, trust your local development certificate
+
+### MCP server not starting
+
+- Ensure Node.js is installed (v22+ recommended, matching .nvmrc)
+- Run `npx @umbraco-cms/mcp-dev@17 --help` to verify the package works
+
+## Further Reading
+
+- [Model Context Protocol Documentation](https://modelcontextprotocol.io/)
+- [Umbraco MCP Package](https://www.npmjs.com/package/@umbraco-cms/mcp-dev)
+- [Playwright MCP](https://www.npmjs.com/package/@playwright/mcp)
+- [Claude Code Documentation](https://docs.anthropic.com/claude-code)

NOTICES.txt

@@ -196,6 +196,14 @@ Copyright: 2013-2024 .NET Foundation and Contributors
 
 ---
 
+Markdig: A fast, powerful, CommonMark compliant, extensible Markdown processor for .NET
+
+URL: https://github.com/xoofx/markdig
+License: BSD-2-Clause license
+Copyright: 2018+, Alexandre Mutel. All rights reserved.
+
+---
+
 Markdown: A library for parsing and compiling Markdown
 
 URL: https://github.com/hey-red/Markdown

build/azure-pipelines.yml

@@ -45,7 +45,7 @@ parameters:
   - name: integrationNonReleaseTestFilter
     displayName: TestFilter used for non-release type builds
     type: string
-    default: "--filter TestCategory!=LongRunning&TestCategory!=NonCritical"
+    default: "TestCategory!=LongRunning&TestCategory!=NonCritical"
   - name: integrationReleaseTestFilter
     displayName: TestFilter used for release type builds
     type: string
@@ -53,7 +53,7 @@ parameters:
   - name: nonWindowsIntegrationNonReleaseTestFilter
     displayName: TestFilter used for non-release type builds on non Windows agents
     type: string
-    default: "--filter TestCategory!=LongRunning&TestCategory!=NonCritical"
+    default: "TestCategory!=LongRunning&TestCategory!=NonCritical"
   - name: nonWindowsIntegrationReleaseTestFilter
     displayName: TestFilter used for release type builds on non Windows agents
     type: string
@@ -107,9 +107,17 @@ stages:
               command: build
               projects: $(solution)
               arguments: "--configuration $(buildConfiguration) --no-restore --property:ContinuousIntegrationBuild=true --property:GeneratePackageOnBuild=true --property:PackageOutputPath=$(Build.ArtifactStagingDirectory)/nupkg"
+          # Publish compiled DLLs for C# API documentation generation
+          # Separate artifact to avoid increasing build_output size for all builds
+          - task: PublishPipelineArtifact@1
+            displayName: Publish DocFX DLLs
+            condition: and(succeeded(), or(eq(variables['build.NBGV_PublicRelease'], 'True'), eq('${{ parameters.buildApiDocs }}', 'True')))
+            inputs:
+              targetPath: $(Build.SourcesDirectory)/src/Umbraco.Cms/bin/Release
+              artifactName: csharp-docs-dlls
           - powershell: |
               dotnet tool install --global CycloneDX
-              dotnet-CycloneDX $(solution) --output $(Build.ArtifactStagingDirectory)/bom --filename bom-dotnet.xml
+              dotnet-CycloneDX $(solution) --spec-version 1.5 --output $(Build.ArtifactStagingDirectory)/bom --filename bom-dotnet.xml
             displayName: 'Generate Backend BOM'
           - powershell: |
               npm install --global @cyclonedx/cyclonedx-npm
@@ -167,6 +175,34 @@ stages:
             artifact: bom-frontend
             displayName: 'Publish Frontend BOM'
 
+      - job: C
+        displayName: Build Test Helpers Package
+        pool:
+          vmImage: "ubuntu-latest"
+        steps:
+          - checkout: self
+            submodules: false
+            lfs: false
+            fetchDepth: 500
+          - template: templates/e2e-install.yml
+            parameters:
+              nodeVersion: ${{ variables.nodeVersion }}
+              npm_config_cache: ${{ variables.npm_config_cache }}
+          - template: templates/set-npm-version.yml
+            parameters:
+              workingDirectory: tests/Umbraco.Tests.AcceptanceTest
+          - bash: |
+              echo "##[command]Running npm pack"
+              mkdir $(Build.ArtifactStagingDirectory)/npm-testhelpers
+              npm pack --pack-destination $(Build.ArtifactStagingDirectory)/npm-testhelpers
+            displayName: Run npm pack
+            workingDirectory: tests/Umbraco.Tests.AcceptanceTest
+          - task: PublishPipelineArtifact@1
+            displayName: Publish Test Helpers npm artifact
+            inputs:
+              targetPath: $(Build.ArtifactStagingDirectory)/npm-testhelpers
+              artifactName: npm-testhelpers
+
   - stage: E2E_BOM
     displayName: E2E Tests BOM Generation
     dependsOn: []
@@ -200,12 +236,22 @@ stages:
     variables:
       umbracoMajorVersion: $[ stageDependencies.Build.A.outputs['build.NBGV_VersionMajor'] ]
     jobs:
-      # C# API Reference
+      # C# API Reference - uses pre-compiled DLLs for faster generation (csproj approach caused timeouts)
       - job:
         displayName: Build C# API Reference
         pool:
           vmImage: "windows-latest"
         steps:
+          - checkout: self
+            submodules: false
+            lfs: false
+            fetchDepth: 1
+            fetchFilter: tree:0
+          - task: DownloadPipelineArtifact@2
+            displayName: Download DocFX DLLs
+            inputs:
+              artifact: csharp-docs-dlls
+              path: $(Build.SourcesDirectory)/src/Umbraco.Cms/bin/Release
           - task: UseDotNet@2
             displayName: Use .NET SDK from global.json
             inputs:
@@ -215,7 +261,7 @@ stages:
             inputs:
               targetType: inline
               script: |
-                choco install docfx --version=2.59.4 -y
+                dotnet tool install -g docfx --version 2.78.4
                 if ($lastexitcode -ne 0){
                     throw ("Error installing DocFX")
                 }
@@ -409,13 +455,13 @@ stages:
               projects: "tests/Umbraco.Tests.Integration/Umbraco.Tests.Integration.csproj"
               testRunTitle: Integration Tests SQLite - $(Agent.OS)
               ${{ if and(eq(variables['Agent.OS'],'Windows_NT'), or(variables.releaseTestFilter, parameters.forceReleaseTestFilter)) }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.integrationReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build'
               ${{ elseif eq(variables['Agent.OS'],'Windows_NT') }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.integrationNonReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter) & ${{parameters.integrationNonReleaseTestFilter}}" --configuration $(buildConfiguration) --no-build'
               ${{ elseif or(variables.releaseTestFilter, parameters.forceReleaseTestFilter) }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.nonWindowsIntegrationReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build'
               ${{ else }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.nonWindowsIntegrationNonReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter) & ${{parameters.nonWindowsIntegrationNonReleaseTestFilter}}" --configuration $(buildConfiguration) --no-build'
       # Integration Tests (SQL Server)
       - job:
         timeoutInMinutes: 180
@@ -523,13 +569,13 @@ stages:
               projects: "tests/Umbraco.Tests.Integration/Umbraco.Tests.Integration.csproj"
               testRunTitle: Integration Tests SQL Server - $(Agent.OS)
               ${{ if and(eq(variables['Agent.OS'],'Windows_NT'), or(variables.releaseTestFilter, parameters.forceReleaseTestFilter)) }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.integrationReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build'
               ${{ elseif eq(variables['Agent.OS'],'Windows_NT') }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.integrationNonReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter) & ${{parameters.integrationNonReleaseTestFilter}}" --configuration $(buildConfiguration) --no-build'
               ${{ elseif or(variables.releaseTestFilter, parameters.forceReleaseTestFilter) }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.nonWindowsIntegrationReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build'
               ${{ else }}:
-                arguments: '--filter "$(testFilter)" --configuration $(buildConfiguration) --no-build ${{parameters.nonWindowsIntegrationNonReleaseTestFilter}}'
+                arguments: '--filter "$(testFilter) & ${{parameters.nonWindowsIntegrationNonReleaseTestFilter}}" --configuration $(buildConfiguration) --no-build'
 
           # Stop SQL Server
           - pwsh: docker stop mssql
@@ -561,7 +607,6 @@ stages:
       UMBRACO__CMS__GLOBAL__VERSIONCHECKPERIOD: 0
       UMBRACO__CMS__GLOBAL__USEHTTPS: true
       UMBRACO__CMS__HEALTHCHECKS__NOTIFICATION__ENABLED: false
-      UMBRACO__CMS__KEEPALIVE__DISABLEKEEPALIVETASK: true
       UMBRACO__CMS__WEBROUTING__UMBRACOAPPLICATIONURL: https://localhost:44331/
       ASPNETCORE_URLS: https://localhost:44331
     jobs:
@@ -780,52 +825,56 @@ stages:
                 publishFeedCredentials: "MyGet - Umbraco Nightly"
               ${{ else }}:
                 publishFeedCredentials: "MyGet - Pre-releases"
+      # Pre-release/nightly feeds: keep the `latest` dist-tag default (no `next` split).
       - job:
         displayName: Push to pre-release feed (npm)
         steps:
-          - checkout: none
-          - download: current
-            artifact: npm
-          - bash: |
-              # Check if we are on a nightly build
-              if [ $isNightly = "False" ]; then
-                  echo "##[debug]Prerelease build detected"
-                  registry="https://www.myget.org/F/umbracoprereleases/npm/"
-              else
-                  echo "##[debug]Nightly build detected"
-                  registry="https://www.myget.org/F/umbraconightly/npm/"
-              fi
-              echo "@umbraco-cms:registry=$registry" >> .npmrc
-            env:
-              isNightly: ${{parameters.isNightly}}
-            workingDirectory: $(Pipeline.Workspace)/npm
-            displayName: Add scoped registry to .npmrc
-          - task: npmAuthenticate@0
-            displayName: Authenticate with npm (MyGet)
-            inputs:
-              workingFile: "$(Pipeline.Workspace)/npm/.npmrc"
+          - template: templates/npm-publish.yml
+            parameters:
+              artifactName: npm
               customEndpoint: "MyGet (npm) - Umbracoprereleases, MyGet (npm) - Umbraconightly"
-          - bash: |
-              # Setup temp npm project to load in defaults from the local .npmrc
-              npm init -y
-
-              # Find the first .tgz file in the current directory and publish it
-              files=( ./*.tgz )
-              npm publish "${files[0]}"
-            displayName: Push to npm (MyGet)
-            workingDirectory: $(Pipeline.Workspace)/npm
+              displayName: Push to npm (MyGet)
+              ${{ if eq(parameters.isNightly, true) }}:
+                registry: https://www.myget.org/F/umbraconightly/npm/
+              ${{ else }}:
+                registry: https://www.myget.org/F/umbracoprereleases/npm/
+      - job: PublishTestHelpersNpm
+        displayName: Push TestHelpers to pre-release feed (npm)
+        steps:
+          - template: templates/npm-publish.yml
+            parameters:
+              artifactName: npm-testhelpers
+              customEndpoint: "MyGet (npm) - Umbracoprereleases, MyGet (npm) - Umbraconightly"
+              displayName: Push test helpers to npm (MyGet)
+              ${{ if eq(parameters.isNightly, true) }}:
+                registry: https://www.myget.org/F/umbraconightly/npm/
+              ${{ else }}:
+                registry: https://www.myget.org/F/umbracoprereleases/npm/
 
   - stage: Deploy_NuGet
     displayName: NuGet release
-    dependsOn:
-      - Deploy_MyGet
-      - Build_Docs
-    condition: and(succeeded(), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.nuGetDeploy}}))
+    dependsOn: Deploy_MyGet
+    # Run only when Deploy_MyGet actually ran (succeeded or failed) — not when it was skipped due to an upstream test failure.
+    # Inspect Deploy_MyGet's direct result rather than succeeded()/failed(), which are transitive across the full ancestor graph.
+    # Approval is required every run via the WaitForApproval job below.
+    condition: and(in(dependencies.Deploy_MyGet.result, 'Succeeded', 'SucceededWithIssues', 'Failed'), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.nuGetDeploy}}))
     jobs:
-      - job:
+      - job: WaitForApproval
+        displayName: Wait for manual approval
+        pool: server
+        steps:
+          - task: ManualValidation@0
+            displayName: Manual approval to push to NuGet
+            timeoutInMinutes: 4320 # 3 days
+            inputs:
+              notifyUsers: ''
+              instructions: 'Approve to push the NuGet release.'
+              onTimeout: 'reject'
+      - job: Push
+        displayName: Push to NuGet
+        dependsOn: WaitForApproval
         pool:
           vmImage: "windows-latest" # NuGetCommand@2 is no longer supported on Ubuntu 24.04 so we'll use windows until an alternative is available.
-        displayName: Push to NuGet
         steps:
           - checkout: none
           - task: DownloadPipelineArtifact@2
@@ -843,33 +892,36 @@ stages:
 
   - stage: Deploy_Npm
     displayName: Npm release
-    condition: and(succeeded(), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.npmDeploy}}))
+    # Inspect Deploy_NuGet.result directly so a MyGet failure (which is in the transitive ancestor graph)
+    # doesn't cascade-skip this stage via succeeded(). Deploy_NuGet must itself have succeeded — a NuGet
+    # failure deliberately blocks the npm release.
+    condition: and(in(dependencies.Deploy_NuGet.result, 'Succeeded', 'SucceededWithIssues'), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.npmDeploy}}))
     dependsOn:
       - Deploy_NuGet
+    variables:
+      # `latest` for stable releases, `next` for prereleases.
+      npmDistTag: $[ iif(eq(stageDependencies.Build.A.outputs['build.NBGV_PrereleaseVersionNoLeadingHyphen'], ''), 'latest', 'next') ]
     jobs:
       - job: Publish
         displayName: Push to NPM
         steps:
-          - checkout: none
-          - download: current
-            artifact: npm
-          - bash: echo "@umbraco-cms:registry=https://registry.npmjs.org" >> .npmrc
-            workingDirectory: $(Pipeline.Workspace)/npm
-            displayName: Add scoped registry to .npmrc
-          - task: npmAuthenticate@0
-            displayName: Authenticate with npm
-            inputs:
-              workingFile: $(Pipeline.Workspace)/npm/.npmrc
+          - template: templates/npm-publish.yml
+            parameters:
+              artifactName: npm
+              registry: https://registry.npmjs.org/
               customEndpoint: "NPM - Umbraco Backoffice"
-          - script: |
-              # Setup temp npm project to load in defaults from the local .npmrc
-              npm init -y
-
-              # Find the first .tgz file in the current directory and publish it
-              files=( ./*.tgz )
-              npm publish "${files[0]}"
-            displayName: Push to npm
-            workingDirectory: $(Pipeline.Workspace)/npm
+              displayName: Push to npm
+              npmTag: $(npmDistTag)
+      - job: PublishTestHelpers
+        displayName: Push Test Helpers to NPM
+        steps:
+          - template: templates/npm-publish.yml
+            parameters:
+              artifactName: npm-testhelpers
+              registry: https://registry.npmjs.org/
+              customEndpoint: "NPM - Umbraco Backoffice"
+              displayName: Push test helpers to npm
+              npmTag: $(npmDistTag)
 
   - stage: Upload_API_Docs
     pool:
@@ -879,8 +931,12 @@ stages:
     displayName: Upload API Documentation
     dependsOn:
       - Build
+      - Build_Docs
       - Deploy_NuGet
-    condition: and(succeeded(), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.uploadApiDocs}}))
+    # Build_Docs must have produced artifacts (we won't upload anything otherwise) and Deploy_NuGet must
+    # have succeeded — a NuGet failure deliberately blocks the docs upload. Direct result checks avoid
+    # transitive succeeded()/failed() which would cascade-skip on a MyGet failure.
+    condition: and(in(dependencies.Build_Docs.result, 'Succeeded', 'SucceededWithIssues'), in(dependencies.Deploy_NuGet.result, 'Succeeded', 'SucceededWithIssues'), or(eq(dependencies.Build.outputs['A.build.NBGV_PublicRelease'], 'True'), ${{parameters.uploadApiDocs}}))
     jobs:
       - job:
         displayName: Upload C# Docs

build/csharp-docs/docfx.json

@@ -3,17 +3,13 @@
     {
       "src": [
         {
-          "src": "../../src",
+          "src": "../../src/Umbraco.Cms/bin/Release",
           "files": [
-            "**/*.csproj"
+            "**/Umbraco.*.dll"
           ],
           "exclude": [
-            "**/obj/**",
-            "**/bin/**",
-            "**/Umbraco.Web.csproj",
-            "**/Umbraco.Web.UI.csproj",
-            "**/Umbraco.Cms.StaticAssets.csproj",
-            "**/JsonSchema.csproj"
+            "**/Umbraco.Cms.StaticAssets.dll",
+            "**/Umbraco.Cms.Targets.dll"
           ]
         }
       ],

build/csharp-docs/umbracotemplate/partials/head.tmpl.partial

@@ -9,7 +9,7 @@
   <meta name="generator" content="docfx {{_docfxVersion}}">
   {{#_description}}<meta name="description" content="{{_description}}">{{/_description}}
   <link rel="icon" type="image/png" href="https://our.umbraco.com/assets/images/app-icons/favicon.png">
-  <link rel="stylesheet" href="{{_rel}}styles/docfx.vendor.css">
+  <link rel="stylesheet" href="{{_rel}}styles/docfx.vendor.min.css">
   <link rel="stylesheet" href="{{_rel}}styles/docfx.css">
   <link rel="stylesheet" href="{{_rel}}styles/main.css">
   <meta property="docfx:navrel" content="{{_navRel}}">

build/nightly-E2E-build-template.yml

@@ -54,11 +54,17 @@ steps:
   - pwsh: |
       $sourcePath = "$(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest/tests/${{ parameters.testFolder }}/AdditionalSetup"
       $destinationPath = "UmbracoProject"
-      $csharpFiles = Get-ChildItem -Path $sourcePath -Filter "*.cs"
+      $csharpFiles = Get-ChildItem -Path $sourcePath -Filter "*.cs" -Recurse
       if ($csharpFiles) {
         $csharpFiles | ForEach-Object {
-          Write-Host "Copying: $($_.FullName)"
-          Copy-Item -Path $_.FullName -Destination $destinationPath -Force
+          $relativePath = $_.FullName.Substring($sourcePath.Length + 1)
+          $targetPath = Join-Path -Path $destinationPath -ChildPath $relativePath
+          $targetDir = Split-Path -Path $targetPath -Parent
+          if (-not (Test-Path -Path $targetDir)) {
+            New-Item -ItemType Directory -Path $targetDir -Force | Out-Null
+          }
+          Write-Host "Copying: $($_.FullName) -> $targetPath"
+          Copy-Item -Path $_.FullName -Destination $targetPath -Force
         }
       } else {
         Write-Host "No C# files found."

build/nightly-E2E-setup-template.yml

@@ -44,7 +44,7 @@ steps:
       $cmsVersion = "$(Build.BuildNumber)" -replace "\+",".g"
       dotnet new nugetconfig
       dotnet nuget add source ./nupkg --name Local
-      dotnet new install Umbraco.Templates::$cmsVersion
-      dotnet new umbraco --name UmbracoProject --version $cmsVersion --exclude-gitignore --no-restore --no-update-check
+      dotnet new install Umbraco.Templates@$cmsVersion
+      dotnet new umbraco --name UmbracoProject --exclude-gitignore --no-restore --no-update-check
     displayName: Install Template
     workingDirectory: $(Agent.BuildDirectory)/app

build/nightly-E2E-test-pipelines.yml

@@ -5,11 +5,9 @@ trigger: none
 
 schedules:
   - cron: '0 0 * * *'
-    displayName: Daily midnight build
+    displayName: Daily 0AM build (main)
     branches:
       include:
-        - v15/dev
-        - v16/dev
         - main
 
 parameters:
@@ -28,6 +26,12 @@ parameters:
     type: boolean
     default: false
 
+  # Can we slow our tests down when running on SQLite? That way we might be able to avoid DB locks
+  - name: skipSqliteAcceptanceTests
+    displayName: Skip SQLite acceptance tests
+    type: boolean
+    default: true
+
 variables:
   nodeVersion: 20
   solution: umbraco.sln
@@ -113,7 +117,7 @@ stages:
   - stage: Integration
     displayName: Integration Tests
     dependsOn: Build
-    condition: ${{ eq(parameters.skipIntegrationTests, false) }}
+    condition: and(succeeded(), ${{ eq(parameters.skipIntegrationTests, false) }})
     jobs:
       # Integration Tests (SQLite)
       - job:
@@ -195,31 +199,37 @@ stages:
           SA_PASSWORD: UmbracoAcceptance123!
         strategy:
           matrix:
-            # We split the tests into 4 parts for each OS to reduce the time it takes to run them on the pipeline
-            WindowsPart1Of4:
+            # Windows is split into 5 parts (ManagementApi split in two to avoid memory pressure on LocalDb); Linux into 4.
+            WindowsPart1Of5:
               vmImage: "windows-latest"
               Tests__Database__DatabaseType: LocalDb
               Tests__Database__SQLServerMasterConnectionString: N/A
               # Filter tests that are part of the Umbraco.Infrastructure namespace but not part of the Umbraco.Infrastructure.Service namespace
               testFilter: "(FullyQualifiedName~Umbraco.Infrastructure) & (FullyQualifiedName!~Umbraco.Infrastructure.Service)"
-            WindowsPart2Of4:
+            WindowsPart2Of5:
               vmImage: "windows-latest"
               Tests__Database__DatabaseType: LocalDb
               Tests__Database__SQLServerMasterConnectionString: N/A
               # Filter tests that are part of the Umbraco.Infrastructure.Service namespace
               testFilter: "(FullyQualifiedName~Umbraco.Infrastructure.Service)"
-            WindowsPart3Of4:
+            WindowsPart3Of5:
               vmImage: "windows-latest"
               Tests__Database__DatabaseType: LocalDb
               Tests__Database__SQLServerMasterConnectionString: N/A
               # Filter tests that are not part of the Umbraco.Infrastructure and ManagementApi namespace.
               testFilter: "(FullyQualifiedName!~Umbraco.Infrastructure) & (FullyQualifiedName!~ManagementApi)"
-            WindowsPart4Of4:
+            WindowsPart4Of5:
               vmImage: "windows-latest"
               Tests__Database__DatabaseType: LocalDb
               Tests__Database__SQLServerMasterConnectionString: N/A
-              # Filter tests that are part of the ManagementApi namespace.
-              testFilter: "(FullyQualifiedName~ManagementApi)"
+              # ManagementApi, heavier sub-namespaces. Trailing dots prevent "User." from matching "UserGroup." etc.
+              testFilter: "FullyQualifiedName~ManagementApi & (FullyQualifiedName~ManagementApi.Element. | FullyQualifiedName~ManagementApi.User. | FullyQualifiedName~ManagementApi.Document. | FullyQualifiedName~ManagementApi.DataType. | FullyQualifiedName~ManagementApi.DocumentType. | FullyQualifiedName~ManagementApi.MediaType. | FullyQualifiedName~ManagementApi.Template.)"
+            WindowsPart5Of5:
+              vmImage: "windows-latest"
+              Tests__Database__DatabaseType: LocalDb
+              Tests__Database__SQLServerMasterConnectionString: N/A
+              # ManagementApi, remainder (complement of Part4). vstest filters do not support group
+              testFilter: "FullyQualifiedName~ManagementApi & FullyQualifiedName!~ManagementApi.Element. & FullyQualifiedName!~ManagementApi.User. & FullyQualifiedName!~ManagementApi.Document. & FullyQualifiedName!~ManagementApi.DataType. & FullyQualifiedName!~ManagementApi.DocumentType. & FullyQualifiedName!~ManagementApi.MediaType. & FullyQualifiedName!~ManagementApi.Template."
             LinuxPart1Of4:
               vmImage: "ubuntu-latest"
               Tests__Database__DatabaseType: SqlServer
@@ -315,7 +325,8 @@ stages:
 
   - stage: DefaultConfigE2E
     displayName: Default Config E2E Tests
-    dependsOn: Build
+    dependsOn: [Build, Integration]
+    condition: in(dependencies.Build.result, 'Succeeded', 'SucceededWithIssues')
     variables:
       npm_config_cache: $(Pipeline.Workspace)/.npm_e2e
       # Enable console logging in Release mode
@@ -334,7 +345,6 @@ stages:
       UMBRACO__CMS__GLOBAL__VERSIONCHECKPERIOD: 0
       UMBRACO__CMS__GLOBAL__USEHTTPS: true
       UMBRACO__CMS__HEALTHCHECKS__NOTIFICATION__ENABLED: false
-      UMBRACO__CMS__KEEPALIVE__DISABLEKEEPALIVETASK: true
       UMBRACO__CMS__WEBROUTING__UMBRACOAPPLICATIONURL: https://localhost:44331/
       ASPNETCORE_URLS: https://localhost:44331
     jobs:
@@ -342,7 +352,7 @@ stages:
       - job:
         displayName: E2E Tests (SQLite)
         timeoutInMinutes: 180
-        condition: ${{ eq(parameters.skipDefaultConfigAcceptanceTests, false) }}
+        condition: ${{ and(eq(parameters.skipDefaultConfigAcceptanceTests, false), eq(parameters.skipSqliteAcceptanceTests, false)) }}
         variables:
           # Connection string
           CONNECTIONSTRINGS__UMBRACODBDSN: Data Source=Umbraco;Mode=Memory;Cache=Shared;Foreign Keys=True;Pooling=True
@@ -496,7 +506,8 @@ stages:
 
   - stage: AdditionalConfigE2E
     displayName: Additional Config E2E Tests
-    dependsOn: Build
+    dependsOn: [Build, DefaultConfigE2E]
+    condition: in(dependencies.Build.result, 'Succeeded', 'SucceededWithIssues')
     variables:
       npm_config_cache: $(Pipeline.Workspace)/.npm_e2e
       ASPNETCORE_URLS: https://localhost:44331
@@ -581,6 +592,23 @@ stages:
               CONNECTIONSTRINGS__UMBRACODBDSN: Server=(local);Database=Umbraco;User Id=sa;Password=$(SA_PASSWORD);Encrypt=True;TrustServerCertificate=True
               CONNECTIONSTRINGS__UMBRACODBDSN_PROVIDERNAME: Microsoft.Data.SqlClient
               additionalEnvironmentVariables: false
+            # ContentSettingConfig
+            WindowsContentSettingsConfig:
+              vmImage: "windows-latest"
+              testFolder: "ContentSettingConfig"
+              port: ''
+              testCommand: "npx playwright test --project=contentSettingConfig"
+              CONNECTIONSTRINGS__UMBRACODBDSN: Data Source=(localdb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Umbraco.mdf;Integrated Security=True
+              CONNECTIONSTRINGS__UMBRACODBDSN_PROVIDERNAME: Microsoft.Data.SqlClient
+              additionalEnvironmentVariables: false
+            LinuxContentSettingsConfig:
+              vmImage: "ubuntu-latest"
+              testFolder: "ContentSettingConfig"
+              port: ''
+              testCommand: "npx playwright test --project=contentSettingConfig"
+              CONNECTIONSTRINGS__UMBRACODBDSN: Server=(local);Database=Umbraco;User Id=sa;Password=$(SA_PASSWORD);Encrypt=True;TrustServerCertificate=True
+              CONNECTIONSTRINGS__UMBRACODBDSN_PROVIDERNAME: Microsoft.Data.SqlClient
+              additionalEnvironmentVariables: false
             # SMTP
             LinuxSMTP:
               vmImage: "ubuntu-latest"
@@ -693,7 +721,7 @@ stages:
               AZUREB2CTESTUSEREMAIL: $(AZUREB2CTESTUSEREMAIL)
               AZUREB2CTESTUSERPASSWORD: $(AZUREB2CTESTUSERPASSWORD)
               DatabaseType: ${{ variables.DatabaseType }}
-          
+
           # Stop SMTP4dev container
           - bash: |
               echo "Stopping SMTP4dev container..."

build/nightly-build-trigger.yml

@@ -10,6 +10,7 @@ schedules:
     include:
     - v13/dev
     - v16/dev
+    - v18/dev
     - main
 
 steps:

build/templates/backoffice-install.yml

@@ -6,16 +6,9 @@ steps:
       versionSource: 'fromFile'
       versionFilePath: src/Umbraco.Web.UI.Client/.nvmrc
 
-  - bash: |
-      echo "##[command]Install nbgv"
-      dotnet tool install --tool-path . nbgv
-      echo "##[command]Running nbgv get-version"
-      PACKAGE_VERSION=$(nbgv get-version -v NpmPackageVersion)
-      echo "##[command]Running npm version"
-      echo "##[debug]Version: $PACKAGE_VERSION"
-      cd src/Umbraco.Web.UI.Client
-      npm version $PACKAGE_VERSION --allow-same-version --no-git-tag-version
-    displayName: Set NPM Version
+  - template: set-npm-version.yml
+    parameters:
+      workingDirectory: src/Umbraco.Web.UI.Client
 
   - task: Cache@2
     displayName: Cache node_modules

build/templates/e2e-install.yml

@@ -29,7 +29,7 @@ steps:
       "UMBRACO_USER_LOGIN=${{ parameters.PlaywrightUserEmail }}
       UMBRACO_USER_PASSWORD=${{ parameters.PlaywrightPassword }}
       URL=${{ parameters.ASPNETCORE_URLS }}
-      STORAGE_STAGE_PATH=$(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest/playwright/.auth/user.json
+      STORAGE_STATE_PATH=$(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest/playwright/.auth/user.json
       CONSOLE_ERRORS_PATH=$(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest/console-errors.json" | Out-File .env
     displayName: Generate .env
     workingDirectory: $(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest
@@ -47,3 +47,7 @@ steps:
   - script: npm ci --no-fund --no-audit --prefer-offline
     workingDirectory: $(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest
     displayName: Restore NPM packages
+
+  - script: npm run build
+    workingDirectory: $(Build.SourcesDirectory)/tests/Umbraco.Tests.AcceptanceTest
+    displayName: Build test helpers

build/templates/npm-publish.yml

@@ -0,0 +1,28 @@
+parameters:
+  - name: artifactName # "npm" or "npm-testhelpers"
+    type: string
+  - name: registry # scoped-registry URL to publish to
+    type: string
+  - name: customEndpoint # npmAuthenticate service connection(s)
+    type: string
+  - name: displayName # label for the publish step
+    type: string
+  - name: npmTag # dist-tag to publish under
+    type: string
+    default: latest
+
+steps:
+  - checkout: none
+  - download: current
+    artifact: ${{ parameters.artifactName }}
+  - script: npm config set @umbraco-cms:registry ${{ parameters.registry }} --location=project
+    displayName: Add scoped registry to .npmrc
+    workingDirectory: $(Pipeline.Workspace)/${{ parameters.artifactName }}
+  - task: npmAuthenticate@0
+    displayName: Authenticate with npm
+    inputs:
+      workingFile: $(Pipeline.Workspace)/${{ parameters.artifactName }}/.npmrc
+      customEndpoint: ${{ parameters.customEndpoint }}
+  - script: npm publish *.tgz --tag ${{ parameters.npmTag }}
+    displayName: ${{ parameters.displayName }}
+    workingDirectory: $(Pipeline.Workspace)/${{ parameters.artifactName }}

build/templates/set-npm-version.yml

@@ -0,0 +1,15 @@
+parameters:
+  - name: workingDirectory
+    type: string
+
+steps:
+  - bash: |
+      echo "##[command]Install nbgv"
+      dotnet tool install --tool-path . nbgv
+      echo "##[command]Running nbgv get-version"
+      PACKAGE_VERSION=$(nbgv get-version -v NpmPackageVersion)
+      echo "##[command]Running npm version"
+      echo "##[debug]Version: $PACKAGE_VERSION"
+      cd ${{ parameters.workingDirectory }}
+      npm version $PACKAGE_VERSION --allow-same-version --no-git-tag-version
+    displayName: Set NPM Version

src/Umbraco.Cms.Api.Common/Accessors/RequestContextOutputExpansionStrategyAccessor.cs

@@ -1,10 +1,17 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Umbraco.Cms.Core.DeliveryApi;
 
 namespace Umbraco.Cms.Api.Common.Accessors;
 
+/// <summary>
+///     Provides access to the <see cref="IOutputExpansionStrategy"/> for the current HTTP request context.
+/// </summary>
 public sealed class RequestContextOutputExpansionStrategyAccessor : RequestContextServiceAccessorBase<IOutputExpansionStrategy>, IOutputExpansionStrategyAccessor
 {
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="RequestContextOutputExpansionStrategyAccessor"/> class.
+    /// </summary>
+    /// <param name="httpContextAccessor">The HTTP context accessor.</param>
     public RequestContextOutputExpansionStrategyAccessor(IHttpContextAccessor httpContextAccessor)
         : base(httpContextAccessor)
     {

src/Umbraco.Cms.Api.Common/Accessors/RequestContextServiceAccessorBase.cs

@@ -1,17 +1,30 @@
-using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Umbraco.Cms.Api.Common.Accessors;
 
+/// <summary>
+///     Base class for accessing request-scoped services from the current HTTP context.
+/// </summary>
+/// <typeparam name="T">The type of service to access.</typeparam>
 public abstract class RequestContextServiceAccessorBase<T>
     where T : class
 {
     private readonly IHttpContextAccessor _httpContextAccessor;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="RequestContextServiceAccessorBase{T}"/> class.
+    /// </summary>
+    /// <param name="httpContextAccessor">The HTTP context accessor.</param>
     protected RequestContextServiceAccessorBase(IHttpContextAccessor httpContextAccessor)
         => _httpContextAccessor = httpContextAccessor;
 
+    /// <summary>
+    ///     Attempts to retrieve the service from the current HTTP context's request services.
+    /// </summary>
+    /// <param name="requestStartNodeService">When this method returns, contains the service instance if found; otherwise, <c>null</c>.</param>
+    /// <returns><c>true</c> if the service was found; otherwise, <c>false</c>.</returns>
     public bool TryGetValue([NotNullWhen(true)] out T? requestStartNodeService)
     {
         requestStartNodeService = _httpContextAccessor.HttpContext?.RequestServices.GetService<T>();

src/Umbraco.Cms.Api.Common/Attributes/MapToApiAttribute.cs

@@ -1,9 +1,19 @@
 namespace Umbraco.Cms.Api.Common.Attributes;
 
+/// <summary>
+///     Attribute used to map a class to a specific API for OpenAPI documentation generation.
+/// </summary>
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
 public class MapToApiAttribute : Attribute
 {
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="MapToApiAttribute"/> class.
+    /// </summary>
+    /// <param name="apiName">The name of the API to map to.</param>
     public MapToApiAttribute(string apiName) => ApiName = apiName;
 
+    /// <summary>
+    ///     Gets the name of the API this class is mapped to.
+    /// </summary>
     public string ApiName { get; }
 }

src/Umbraco.Cms.Api.Common/Builders/ProblemDetailsBuilder.cs

@@ -1,9 +1,12 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Umbraco.Extensions;
 
 namespace Umbraco.Cms.Api.Common.Builders;
 
+/// <summary>
+///     A fluent builder for creating RFC 7807 <see cref="ProblemDetails"/> responses.
+/// </summary>
 public class ProblemDetailsBuilder
 {
     private string? _title;
@@ -12,24 +15,45 @@ public class ProblemDetailsBuilder
     private string? _operationStatus;
     private IDictionary<string, object>? _extensions;
 
+    /// <summary>
+    ///     Sets the title of the problem details.
+    /// </summary>
+    /// <param name="title">A short, human-readable summary of the problem type.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithTitle(string title)
     {
         _title = title;
         return this;
     }
 
+    /// <summary>
+    ///     Sets the detail of the problem details.
+    /// </summary>
+    /// <param name="detail">A human-readable explanation specific to this occurrence of the problem.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithDetail(string detail)
     {
         _detail = detail;
         return this;
     }
 
+    /// <summary>
+    ///     Sets the type of the problem details.
+    /// </summary>
+    /// <param name="type">A URI reference that identifies the problem type.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithType(string type)
     {
         _type = type;
         return this;
     }
 
+    /// <summary>
+    ///     Sets the operation status from an enum value.
+    /// </summary>
+    /// <typeparam name="TEnum">The enum type representing operation statuses.</typeparam>
+    /// <param name="operationStatus">The operation status enum value.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithOperationStatus<TEnum>(TEnum operationStatus)
         where TEnum : Enum
     {
@@ -37,9 +61,20 @@ public class ProblemDetailsBuilder
         return this;
     }
 
+    /// <summary>
+    ///     Adds request model validation errors to the problem details.
+    /// </summary>
+    /// <param name="errors">A dictionary of field names to error messages.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithRequestModelErrors(IDictionary<string, string[]> errors)
         => WithExtension(nameof(HttpValidationProblemDetails.Errors).ToFirstLowerInvariant(), errors);
 
+    /// <summary>
+    ///     Adds a custom extension to the problem details.
+    /// </summary>
+    /// <param name="key">The extension key.</param>
+    /// <param name="value">The extension value.</param>
+    /// <returns>The current builder instance for method chaining.</returns>
     public ProblemDetailsBuilder WithExtension(string key, object value)
     {
         _extensions ??= new Dictionary<string, object>();
@@ -47,6 +82,10 @@ public class ProblemDetailsBuilder
         return this;
     }
 
+    /// <summary>
+    ///     Builds the <see cref="ProblemDetails"/> instance with all configured values.
+    /// </summary>
+    /// <returns>A new <see cref="ProblemDetails"/> instance.</returns>
     public ProblemDetails Build()
     {
         var problemDetails = new ProblemDetails

src/Umbraco.Cms.Api.Common/CLAUDE.md

@@ -13,7 +13,8 @@ Shared infrastructure for Umbraco CMS REST APIs (Management and Delivery).
 ### Key Technologies
 
 - **ASP.NET Core** - Web framework
-- **Swashbuckle** - OpenAPI/Swagger documentation generation
+- **Microsoft.AspNetCore.OpenApi** - OpenAPI document generation
+- **Swashbuckle.AspNetCore.SwaggerUI** - Swagger UI for browsing API documentation
 - **OpenIddict** - OAuth 2.0/OpenID Connect authentication
 - **Asp.Versioning** - API versioning
 - **System.Text.Json** - Polymorphic JSON serialization
@@ -27,14 +28,18 @@ Shared infrastructure for Umbraco CMS REST APIs (Management and Delivery).
 
 ```
 Umbraco.Cms.Api.Common/
-├── OpenApi/                    # Schema/Operation ID handlers for Swagger
-│   ├── SchemaIdHandler.cs     # Generates schema IDs (e.g., "PagedUserModel")
-│   ├── OperationIdHandler.cs  # Generates operation IDs
-│   └── SubTypesHandler.cs     # Polymorphism support
+├── OpenApi/                    # OpenAPI transformers and schema generators
+│   ├── UmbracoSchemaIdGenerator.cs         # Generates schema IDs (e.g., "PagedUserModel")
+│   ├── UmbracoOperationIdTransformer.cs    # Generates operation IDs
+│   ├── SortTagsAndPathsTransformer.cs      # Sorts OpenAPI tags and paths
+│   ├── TagActionsByGroupNameTransformer.cs # Tags operations by controller group
+│   ├── FixFileReturnTypesTransformer.cs    # Fixes file return type schemas
+│   ├── RequireNonNullablePropertiesSchemaTransformer.cs # Schema nullability
+│   └── OpenApiRouteTemplatePipelineFilter.cs # Adds OpenAPI endpoints
 ├── Serialization/              # JSON type resolution
 │   └── UmbracoJsonTypeInfoResolver.cs
 ├── Configuration/              # Options configuration
-│   ├── ConfigureUmbracoSwaggerGenOptions.cs
+│   ├── ConfigureUmbracoOpenApiOptionsBase.cs
 │   └── ConfigureOpenIddict.cs
 ├── DependencyInjection/        # Service registration
 │   ├── UmbracoBuilderApiExtensions.cs
@@ -47,9 +52,8 @@ Umbraco.Cms.Api.Common/
 
 ### Design Patterns
 
-1. **Strategy Pattern** - `ISchemaIdHandler`, `IOperationIdHandler` (extensible via inheritance)
-2. **Builder Pattern** - `ProblemDetailsBuilder` for fluent error responses
-3. **Options Pattern** - All configuration via `IConfigureOptions<T>`
+1. **Builder Pattern** - `ProblemDetailsBuilder` for fluent error responses
+2. **Options Pattern** - All configuration via `IConfigureOptions<T>`
 
 ---
 
@@ -61,25 +65,12 @@ See "Quick Reference" section at bottom for common commands.
 
 ## 3. Key Patterns
 
-### Virtual Handlers for Extensibility
+### Schema ID Generation (OpenApi/UmbracoSchemaIdGenerator.cs)
 
-Handlers are intentionally virtual to allow consuming APIs to override:
+Static utility class that generates OpenAPI schema IDs following Umbraco's naming conventions:
 
 ```csharp
-// NOTE: Left unsealed on purpose, so it is extendable.
-public class SchemaIdHandler : ISchemaIdHandler
-{
-    public virtual bool CanHandle(Type type) { }
-    public virtual string Handle(Type type) { }
-}
-```
-
-**Why**: Management and Delivery APIs can customize schema/operation ID generation.
-
-### Schema ID Sanitization (OpenApi/SchemaIdHandler.cs:24-29, 32)
-
-```csharp
-// Add "Model" suffix to avoid TypeScript name clashes (lines 24-29)
+// Add "Model" suffix to avoid TypeScript name clashes
 if (name.EndsWith("Model") == false)
 {
     // because some models names clash with common classes in TypeScript (i.e. Document),
@@ -87,10 +78,12 @@ if (name.EndsWith("Model") == false)
     name = $"{name}Model";
 }
 
-// Remove invalid characters to prevent OpenAPI generation errors (line 32)
+// Remove invalid characters to prevent OpenAPI generation errors
 return Regex.Replace(name, @"[^\w]", string.Empty);
 ```
 
+**Generic Type Handling**: `PagedViewModel<RelationItemViewModel>` becomes `PagedRelationItemModel`
+
 ### Polymorphic Deserialization (Serialization/UmbracoJsonTypeInfoResolver.cs:29-35)
 
 ```csharp
@@ -116,9 +109,12 @@ if (type.IsInterface is false)
 dotnet test tests/Umbraco.Tests.Integration/
 
 # Verify OpenAPI generation
-# 1. Run Management API
-# 2. Navigate to /umbraco/swagger/
+# 1. Run the application: dotnet run --project src/Umbraco.Web.UI
+# 2. Navigate to /umbraco/openapi/ for Swagger UI
 # 3. Check schema IDs and operation IDs
+# OpenAPI JSON documents available at:
+#   - /umbraco/openapi/management.json (Management API)
+#   - /umbraco/openapi/delivery.json (Delivery API)
 ```
 
 **Focus areas when testing**:
@@ -207,49 +203,24 @@ catch (NotSupportedException exception)
 
 **Issue**: Type names like `Document` clash with TypeScript built-ins.
 
-**Solution**: Add "Model" suffix (OpenApi/SchemaIdHandler.cs:24-29)
+**Solution**: `UmbracoSchemaIdGenerator` adds "Model" suffix to all schema names.
 
 ### Generic Type Handling
 
 **Issue**: `PagedViewModel<T>` needs flattened schema name.
 
-**Solution** (OpenApi/SchemaIdHandler.cs:41-50):
-```csharp
-private string HandleGenerics(string name, Type type)
-{
-    if (!type.IsGenericType)
-        return name;
-
-    // use attribute custom name or append the generic type names
-    // turns "PagedViewModel<RelationItemViewModel>" into "PagedRelationItem"
-    return $"{name}{string.Join(string.Empty, type.GenericTypeArguments.Select(SanitizedTypeName))}";
-}
-```
+**Solution**: `UmbracoSchemaIdGenerator.Generate()` flattens generic types:
+- `PagedViewModel<RelationItemViewModel>` becomes `PagedRelationItemModel`
 
 ---
 
 ## 7. Extending This Library
 
-### Adding a Custom OpenAPI Handler
+### Adding Custom OpenAPI Transformers
 
-1. **Implement interface**:
-   ```csharp
-   public class MySchemaIdHandler : SchemaIdHandler
-   {
-       public override bool CanHandle(Type type)
-           => type.Namespace?.StartsWith("MyProject") is true;
+OpenAPI transformers are scoped per-document. To customize a document, implement `IOpenApiDocumentTransformer`, `IOpenApiOperationTransformer`, or `IOpenApiSchemaTransformer` and register with your OpenAPI options.
 
-       public override string Handle(Type type)
-           => $"My{base.Handle(type)}";
-   }
-   ```
-
-2. **Register in consuming API**:
-   ```csharp
-   builder.Services.AddSingleton<ISchemaIdHandler, MySchemaIdHandler>();
-   ```
-
-**Note**: Handlers registered later take precedence in the selector.
+For schema ID generation, use the static `UmbracoSchemaIdGenerator.Generate(Type)` method.
 
 ### Customizing Problem Details
 
@@ -269,13 +240,9 @@ return BadRequest(problemDetails);
 
 ## 8. Project-Specific Notes
 
-### Why Virtual Handlers?
+### Per-Document Transformer Scoping
 
-**Decision**: Make `SchemaIdHandler`, `OperationIdHandler`, etc. virtual.
-
-**Why**: Management API and Delivery API have different schema ID requirements. Virtual methods allow override without rewriting the entire handler.
-
-**Example**: Management API might prefix all schemas with "Management", Delivery API with "Delivery".
+With Microsoft.AspNetCore.OpenApi, transformers are configured per OpenAPI document. This means custom transformers only apply to the documents they're registered with, not globally. Each API (Management, Delivery) configures its own transformers via `ConfigureUmbracoOpenApiOptionsBase` subclasses.
 
 ### Performance: Subtype Caching
 
@@ -304,9 +271,13 @@ return BadRequest(problemDetails);
 - Version: See `Directory.Packages.props`
 - Uses ASP.NET Core Data Protection for token encryption
 
-**Swashbuckle**:
-- OpenAPI 3.0 document generation
-- Custom filters: `EnumSchemaFilter`, `MimeTypeDocumentFilter`, `RemoveSecuritySchemesDocumentFilter`
+**Microsoft.AspNetCore.OpenApi**:
+- OpenAPI 3.1.1 document generation
+- Custom transformers: `SchemaIdTransformer`, `OperationIdTransformer`, `MimeTypeDocumentTransformer`, `ServerTransformer`
+
+**Swashbuckle.AspNetCore.SwaggerUI**:
+- Swagger UI for browsing and testing API endpoints
+- Accessed at `/umbraco/openapi/`
 
 **Asp.Versioning**:
 - API versioning via `ApiVersion` attribute
@@ -318,7 +289,7 @@ return BadRequest(problemDetails);
 
 ### Usage Pattern
 
-Consuming APIs call `builder.AddUmbracoApiOpenApiUI().AddUmbracoOpenIddict()`
+Consuming APIs call `builder.AddUmbracoOpenApi().AddUmbracoOpenIddict()`
 
 ---
 
@@ -346,7 +317,8 @@ dotnet list src/Umbraco.Cms.Api.Common/Umbraco.Cms.Api.Common.csproj package --v
 | Class | Purpose | File |
 |-------|---------|------|
 | `ProblemDetailsBuilder` | Build RFC 7807 error responses | Builders/ProblemDetailsBuilder.cs |
-| `SchemaIdHandler` | Generate OpenAPI schema IDs | OpenApi/SchemaIdHandler.cs |
+| `UmbracoSchemaIdGenerator` | Generate OpenAPI schema IDs | OpenApi/UmbracoSchemaIdGenerator.cs |
+| `UmbracoOperationIdTransformer` | Generate operation IDs | OpenApi/UmbracoOperationIdTransformer.cs |
 | `UmbracoJsonTypeInfoResolver` | Polymorphic JSON serialization | Serialization/UmbracoJsonTypeInfoResolver.cs |
 | `UmbracoBuilderAuthExtensions` | Configure OpenIddict | DependencyInjection/UmbracoBuilderAuthExtensions.cs |
 | `HideBackOfficeTokensHandler` | Secure cookie-based token storage | DependencyInjection/HideBackOfficeTokensHandler.cs |

src/Umbraco.Cms.Api.Common/Configuration/ConfigureApiBehaviorOptions.cs

@@ -1,10 +1,14 @@
-using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Options;
 
 namespace Umbraco.Cms.Api.Common.Configuration;
 
+/// <summary>
+///     Configures <see cref="ApiBehaviorOptions"/> for Umbraco APIs.
+/// </summary>
 public class ConfigureApiBehaviorOptions : IConfigureOptions<ApiBehaviorOptions>
 {
+    /// <inheritdoc/>
     public void Configure(ApiBehaviorOptions options) =>
         // disable ProblemDetails as default result type for every non-success response (i.e. 404)
         // - see https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.mvc.apibehavioroptions.suppressmapclienterrors

src/Umbraco.Cms.Api.Common/Configuration/ConfigureDefaultApiOptions.cs

@@ -0,0 +1,47 @@
+using System.Reflection;
+using Asp.Versioning;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.ApiExplorer;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Umbraco.Cms.Api.Common.OpenApi;
+
+namespace Umbraco.Cms.Api.Common.Configuration;
+
+/// <summary>
+/// Configures the OpenAPI options for the Default API.
+/// </summary>
+internal class ConfigureDefaultApiOptions : ConfigureUmbracoOpenApiOptionsBase
+{
+    /// <inheritdoc />
+    protected override string ApiName => DefaultApiConfiguration.ApiName;
+
+    /// <inheritdoc />
+    protected override string ApiTitle => "Default API";
+
+    /// <inheritdoc />
+    protected override string ApiVersion => "Latest";
+
+    /// <inheritdoc />
+    protected override string ApiDescription => "All endpoints not defined under specific APIs";
+
+    /// <inheritdoc />
+    protected override bool ShouldInclude(ApiDescription apiDescription)
+    {
+        // Exclude controllers with ExcludeFromDefaultOpenApiDocumentAttribute
+        if (apiDescription.ActionDescriptor is ControllerActionDescriptor controllerActionDescriptor
+            && controllerActionDescriptor.ControllerTypeInfo.GetCustomAttribute<ExcludeFromDefaultOpenApiDocumentAttribute>() is not null)
+        {
+            return false;
+        }
+
+        // Include if explicitly mapped to this document
+        if (base.ShouldInclude(apiDescription))
+        {
+            return true;
+        }
+
+        // Include endpoints not explicitly assigned to another document
+        ApiVersionMetadata apiVersionMetadata = apiDescription.ActionDescriptor.ApiVersionMetadata;
+        return string.IsNullOrEmpty(apiVersionMetadata.Name);
+    }
+}

src/Umbraco.Cms.Api.Common/Configuration/ConfigureMvcJsonOptions.cs

@@ -5,12 +5,21 @@ using Umbraco.Cms.Api.Common.Json;
 
 namespace Umbraco.Cms.Api.Common.Configuration;
 
+/// <summary>
+///     Configures <see cref="MvcOptions"/> with named JSON input and output formatters for Umbraco APIs.
+/// </summary>
 public class ConfigureMvcJsonOptions : IConfigureOptions<MvcOptions>
 {
     private readonly string _jsonOptionsName;
     private readonly IOptionsMonitor<JsonOptions> _jsonOptions;
     private readonly ILoggerFactory _loggerFactory;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="ConfigureMvcJsonOptions"/> class.
+    /// </summary>
+    /// <param name="jsonOptionsName">The name of the JSON options configuration to use.</param>
+    /// <param name="jsonOptions">The JSON options monitor.</param>
+    /// <param name="loggerFactory">The logger factory.</param>
     public ConfigureMvcJsonOptions(
         string jsonOptionsName,
         IOptionsMonitor<JsonOptions> jsonOptions,
@@ -21,6 +30,7 @@ public class ConfigureMvcJsonOptions : IConfigureOptions<MvcOptions>
         _loggerFactory = loggerFactory;
     }
 
+    /// <inheritdoc/>
     public void Configure(MvcOptions options)
     {
         JsonOptions jsonOptions = _jsonOptions.Get(_jsonOptionsName);

src/Umbraco.Cms.Api.Common/Configuration/ConfigureOpenIddict.cs

@@ -4,12 +4,24 @@ using Umbraco.Cms.Core.Configuration.Models;
 
 namespace Umbraco.Cms.Api.Common.Configuration;
 
+/// <summary>
+///     Configures OpenIddict server options for Umbraco authentication.
+/// </summary>
+/// <remarks>
+///     Disables transport security requirement when HTTPS is not configured in global settings.
+///     Warning: This should only be used in development environments.
+/// </remarks>
 internal sealed class ConfigureOpenIddict : IConfigureOptions<OpenIddictServerAspNetCoreOptions>
 {
     private readonly IOptions<GlobalSettings> _globalSettings;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="ConfigureOpenIddict"/> class.
+    /// </summary>
+    /// <param name="globalSettings">The global settings options.</param>
     public ConfigureOpenIddict(IOptions<GlobalSettings> globalSettings) => _globalSettings = globalSettings;
 
+    /// <inheritdoc/>
     public void Configure(OpenIddictServerAspNetCoreOptions options)
         => options.DisableTransportSecurityRequirement = _globalSettings.Value.UseHttps is false;
 }

src/Umbraco.Cms.Api.Common/Configuration/ConfigureUmbracoOpenApiOptionsBase.cs

@@ -0,0 +1,98 @@
+using Asp.Versioning;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.ApiExplorer;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.Extensions.Options;
+using Microsoft.OpenApi;
+using Umbraco.Cms.Api.Common.OpenApi;
+using Umbraco.Extensions;
+
+namespace Umbraco.Cms.Api.Common.Configuration;
+
+/// <summary>
+/// Base class for configuring OpenAPI options for Umbraco APIs.
+/// </summary>
+internal abstract class ConfigureUmbracoOpenApiOptionsBase : IConfigureNamedOptions<OpenApiOptions>
+{
+    /// <summary>
+    ///  Gets the name/identifier of the API to configure.
+    /// </summary>
+    protected abstract string ApiName { get; }
+
+    /// <summary>
+    ///  Gets the name/identifier of the API to configure.
+    /// </summary>
+    protected abstract string ApiTitle { get; }
+
+    /// <summary>
+    ///  Gets the version of the API to configure.
+    /// </summary>
+    protected abstract string ApiVersion { get; }
+
+    /// <summary>
+    ///  Gets the description of the API to configure.
+    /// </summary>
+    protected abstract string ApiDescription { get; }
+
+    /// <inheritdoc />
+    public void Configure(OpenApiOptions options) => Configure(Options.DefaultName, options);
+
+    /// <inheritdoc />
+    public void Configure(string? name, OpenApiOptions options)
+    {
+        if (name != ApiName)
+        {
+            return;
+        }
+
+        ConfigureOpenApi(options);
+    }
+
+    /// <summary>
+    /// Configure the OpenAPI options for the specified API.
+    /// </summary>
+    /// <param name="options">The <see cref="OpenApiOptions"/> instance to configure.</param>
+    protected virtual void ConfigureOpenApi(OpenApiOptions options)
+    {
+        options.AddDocumentTransformer((document, _, _) =>
+        {
+            document.Info = new OpenApiInfo
+            {
+                Title = ApiTitle,
+                Version = ApiVersion,
+                Description = ApiDescription,
+            };
+            document.Servers?.Clear();
+            return Task.CompletedTask;
+        });
+
+        options.ShouldInclude = ShouldInclude;
+        options.CreateSchemaReferenceId = UmbracoSchemaIdGenerator.CreateSchemaReferenceId;
+
+        options.AddOperationTransformer<UmbracoOperationIdTransformer>();
+
+        // Tag actions by group name and cleanup unused tags (caused by the tag changes)
+        options
+            .AddOperationTransformer<TagActionsByGroupNameTransformer>()
+            .AddDocumentTransformer<TagActionsByGroupNameTransformer>()
+            .AddDocumentTransformer<SortTagsAndPathsTransformer>();
+    }
+
+    /// <summary>
+    /// Determines whether the specified API description should be included in this OpenAPI document.
+    /// </summary>
+    /// <param name="apiDescription">The API description to evaluate.</param>
+    /// <returns><c>true</c> if the endpoint should be included; otherwise, <c>false</c>.</returns>
+    protected virtual bool ShouldInclude(ApiDescription apiDescription)
+    {
+        if (apiDescription.ActionDescriptor is ControllerActionDescriptor controllerActionDescriptor
+            && controllerActionDescriptor.HasMapToApiAttribute(ApiName))
+        {
+            return true;
+        }
+
+        ApiVersionMetadata apiVersionMetadata = apiDescription.ActionDescriptor.ApiVersionMetadata;
+        return apiVersionMetadata.Name == ApiName;
+    }
+}

src/Umbraco.Cms.Api.Common/Configuration/ConfigureUmbracoSwaggerGenOptions.cs

@@ -1,70 +0,0 @@
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Options;
-using Microsoft.OpenApi;
-using Swashbuckle.AspNetCore.SwaggerGen;
-using Umbraco.Cms.Api.Common.OpenApi;
-using Umbraco.Cms.Core.DependencyInjection;
-
-namespace Umbraco.Cms.Api.Common.Configuration;
-
-public class ConfigureUmbracoSwaggerGenOptions : IConfigureOptions<SwaggerGenOptions>
-{
-    private readonly IOperationIdSelector _operationIdSelector;
-    private readonly ISchemaIdSelector _schemaIdSelector;
-    private readonly ISubTypesSelector _subTypesSelector;
-    private readonly IDocumentInclusionSelector _documentInclusionSelector;
-
-    public ConfigureUmbracoSwaggerGenOptions(
-        IOperationIdSelector operationIdSelector,
-        ISchemaIdSelector schemaIdSelector,
-        ISubTypesSelector subTypesSelector,
-        IDocumentInclusionSelector documentInclusionSelector)
-    {
-        _operationIdSelector = operationIdSelector;
-        _schemaIdSelector = schemaIdSelector;
-        _subTypesSelector = subTypesSelector;
-        _documentInclusionSelector = documentInclusionSelector;
-    }
-
-    [Obsolete("Please use the constructor with all parameters. Scheduled for removal in Umbraco 19.")]
-    public ConfigureUmbracoSwaggerGenOptions(
-        IOperationIdSelector operationIdSelector,
-        ISchemaIdSelector schemaIdSelector,
-        ISubTypesSelector subTypesSelector)
-        : this(
-              operationIdSelector,
-              schemaIdSelector,
-              subTypesSelector,
-              StaticServiceProvider.Instance.GetRequiredService<IDocumentInclusionSelector>())
-    {
-    }
-
-    public void Configure(SwaggerGenOptions swaggerGenOptions)
-    {
-        swaggerGenOptions.SwaggerDoc(
-            DefaultApiConfiguration.ApiName,
-            new OpenApiInfo
-            {
-                Title = "Default API",
-                Version = "Latest",
-                Description = "All endpoints not defined under specific APIs",
-            });
-
-        swaggerGenOptions.CustomOperationIds(description => _operationIdSelector.OperationId(description));
-        swaggerGenOptions.DocInclusionPredicate(_documentInclusionSelector.Include);
-        swaggerGenOptions.TagActionsBy(api =>
-            api.GroupName is null
-                ? []
-                : new[] { api.GroupName });
-        swaggerGenOptions.OrderActionsBy(ActionOrderBy);
-        swaggerGenOptions.SchemaFilter<EnumSchemaFilter>();
-        swaggerGenOptions.CustomSchemaIds(_schemaIdSelector.SchemaId);
-        swaggerGenOptions.SelectSubTypesUsing(_subTypesSelector.SubTypes);
-        swaggerGenOptions.SupportNonNullableReferenceTypes();
-    }
-
-    // see https://github.com/domaindrivendev/Swashbuckle.AspNetCore#change-operation-sort-order-eg-for-ui-sorting
-    private static string ActionOrderBy(ApiDescription apiDesc)
-        => $"{apiDesc.GroupName}_{apiDesc.ActionDescriptor.AttributeRouteInfo?.Template ?? apiDesc.ActionDescriptor.RouteValues["controller"]}_{(apiDesc.ActionDescriptor.RouteValues.TryGetValue("action", out var action) ? action : null)}_{apiDesc.HttpMethod}";
-}

src/Umbraco.Cms.Api.Common/Configuration/DefaultApiConfiguration.cs

@@ -1,6 +1,12 @@
 namespace Umbraco.Cms.Api.Common.Configuration;
 
+/// <summary>
+///     Contains default configuration values for the API.
+/// </summary>
 internal static class DefaultApiConfiguration
 {
+    /// <summary>
+    ///     The default API name used for endpoints not assigned to a specific API.
+    /// </summary>
     public const string ApiName = "default";
 }

src/Umbraco.Cms.Api.Common/DependencyInjection/HideBackOfficeTokensHandler.cs

@@ -1,7 +1,10 @@
 using System.Diagnostics.CodeAnalysis;
+using System.Security.Cryptography;
 using Microsoft.AspNetCore.DataProtection;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using OpenIddict.Abstractions;
 using OpenIddict.Server;
 using OpenIddict.Validation;
 using Umbraco.Cms.Core;
@@ -13,10 +16,19 @@ using Umbraco.Extensions;
 
 namespace Umbraco.Cms.Api.Common.DependencyInjection;
 
+/// <summary>
+///     Handles secure storage of back-office authentication tokens in HTTP-only cookies.
+/// </summary>
+/// <remarks>
+///     This handler intercepts OpenIddict token responses for the back-office client and stores
+///     access tokens, refresh tokens, and PKCE codes in encrypted HTTP-only cookies. The tokens
+///     are redacted from the response to prevent client-side JavaScript access.
+/// </remarks>
 internal sealed class HideBackOfficeTokensHandler
     : IOpenIddictServerHandler<OpenIddictServerEvents.ApplyTokenResponseContext>,
         IOpenIddictServerHandler<OpenIddictServerEvents.ApplyAuthorizationResponseContext>,
         IOpenIddictServerHandler<OpenIddictServerEvents.ExtractTokenRequestContext>,
+        IOpenIddictServerHandler<OpenIddictServerEvents.ExtractRevocationRequestContext>,
         IOpenIddictValidationHandler<OpenIddictValidationEvents.ProcessAuthenticationContext>,
         INotificationHandler<UserLogoutSuccessNotification>
 {
@@ -25,25 +37,44 @@ internal sealed class HideBackOfficeTokensHandler
     // The __Host- prefix enforces secure cookies at browser level (requires Secure, Path=/, no Domain).
     // For local development over HTTP, we use a simpler prefix to avoid browser rejection.
     private const string SecureCookiePrefix = "__Host-";
-    private const string AccessTokenCookieName = "umbAccessToken";
-    private const string RefreshTokenCookieName = "umbRefreshToken";
-    private const string PkceCodeCookieName = "umbPkceCode";
+    private readonly string _accessTokenCookieName = "umbAccessToken";
+    private readonly string _refreshTokenCookieName = "umbRefreshToken";
+    private readonly string _pkceCodeCookieName = "umbPkceCode";
 
     private readonly IHttpContextAccessor _httpContextAccessor;
     private readonly IDataProtectionProvider _dataProtectionProvider;
+    private readonly ILogger<HideBackOfficeTokensHandler> _logger;
+#pragma warning disable CS0618 // Type or member is obsolete
     private readonly BackOfficeTokenCookieSettings _backOfficeTokenCookieSettings;
+#pragma warning restore CS0618 // Type or member is obsolete
     private readonly GlobalSettings _globalSettings;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="HideBackOfficeTokensHandler"/> class.
+    /// </summary>
+    /// <param name="httpContextAccessor">The HTTP context accessor.</param>
+    /// <param name="dataProtectionProvider">The data protection provider for encrypting cookie values.</param>
+    /// <param name="logger">The logger.</param>
+    /// <param name="backOfficeTokenCookieSettings">The back-office token cookie settings.</param>
+    /// <param name="globalSettings">The global settings.</param>
     public HideBackOfficeTokensHandler(
         IHttpContextAccessor httpContextAccessor,
         IDataProtectionProvider dataProtectionProvider,
+        ILogger<HideBackOfficeTokensHandler> logger,
+#pragma warning disable CS0618 // Type or member is obsolete
         IOptions<BackOfficeTokenCookieSettings> backOfficeTokenCookieSettings,
+#pragma warning restore CS0618 // Type or member is obsolete
         IOptions<GlobalSettings> globalSettings)
     {
         _httpContextAccessor = httpContextAccessor;
         _dataProtectionProvider = dataProtectionProvider;
+        _logger = logger;
         _backOfficeTokenCookieSettings = backOfficeTokenCookieSettings.Value;
         _globalSettings = globalSettings.Value;
+
+        _accessTokenCookieName += _backOfficeTokenCookieSettings.SiteName;
+        _refreshTokenCookieName += _backOfficeTokenCookieSettings.SiteName;
+        _pkceCodeCookieName += _backOfficeTokenCookieSettings.SiteName;
     }
 
     /// <summary>
@@ -63,13 +94,13 @@ internal sealed class HideBackOfficeTokensHandler
 
         if (context.Response.AccessToken is not null)
         {
-            SetCookie(httpContext, AccessTokenCookieName, context.Response.AccessToken);
+            SetCookie(httpContext, _accessTokenCookieName, context.Response.AccessToken);
             context.Response.AccessToken = RedactedTokenValue;
         }
 
         if (context.Response.RefreshToken is not null)
         {
-            SetCookie(httpContext, RefreshTokenCookieName, context.Response.RefreshToken);
+            SetCookie(httpContext, _refreshTokenCookieName, context.Response.RefreshToken);
             context.Response.RefreshToken = RedactedTokenValue;
         }
 
@@ -91,7 +122,7 @@ internal sealed class HideBackOfficeTokensHandler
 
         if (context.Response.Code is not null)
         {
-            SetCookie(GetHttpContext(), PkceCodeCookieName, context.Response.Code);
+            SetCookie(GetHttpContext(), _pkceCodeCookieName, context.Response.Code);
             context.Response.Code = RedactedTokenValue;
         }
 
@@ -113,12 +144,12 @@ internal sealed class HideBackOfficeTokensHandler
 
         // Handle when the PKCE code is being exchanged for an access token.
         if (context.Request.Code == RedactedTokenValue
-            && TryGetCookie(httpContext, PkceCodeCookieName, out var code))
+            && TryGetCookie(httpContext, _pkceCodeCookieName, out var code))
         {
             context.Request.Code = code;
 
             // We won't need the PKCE cookie after this, let's remove it.
-            RemoveCookie(httpContext, PkceCodeCookieName);
+            RemoveCookie(httpContext, _pkceCodeCookieName);
         }
         else
         {
@@ -129,7 +160,7 @@ internal sealed class HideBackOfficeTokensHandler
 
         // Handle when a refresh token is being exchanged for a new access token.
         if (context.Request.RefreshToken == RedactedTokenValue
-            && TryGetCookie(httpContext, RefreshTokenCookieName, out var refreshToken))
+            && TryGetCookie(httpContext, _refreshTokenCookieName, out var refreshToken))
         {
             context.Request.RefreshToken = refreshToken;
         }
@@ -144,6 +175,40 @@ internal sealed class HideBackOfficeTokensHandler
         return ValueTask.CompletedTask;
     }
 
+    /// <summary>
+    /// This is invoked when a token revocation request is received.
+    /// </summary>
+    public ValueTask HandleAsync(OpenIddictServerEvents.ExtractRevocationRequestContext context)
+    {
+        if (context.Request?.ClientId != Constants.OAuthClientIds.BackOffice)
+        {
+            // Only ever handle the back-office client.
+            return ValueTask.CompletedTask;
+        }
+
+        HttpContext httpContext = GetHttpContext();
+
+        // Determine which cookie to read based on the token type hint.
+        var cookieName = context.Request.TokenTypeHint == OpenIddictConstants.TokenTypeHints.RefreshToken
+            ? _refreshTokenCookieName
+            : _accessTokenCookieName;
+
+        if (context.Request.Token == RedactedTokenValue
+            && TryGetCookie(httpContext, cookieName, out var token))
+        {
+            context.Request.Token = token;
+        }
+        else
+        {
+            // If we got here, either the token was not redacted, or nothing was found in the expected cookie.
+            // If OpenIddict found a token, it could be an old token that is potentially still valid. For security
+            // reasons, we cannot accept that; at this point, we expect the tokens to be explicitly redacted.
+            context.Request.Token = null;
+        }
+
+        return ValueTask.CompletedTask;
+    }
+
     /// <summary>
     /// This is invoked when extracting the auth context for a client request.
     /// </summary>
@@ -155,7 +220,7 @@ internal sealed class HideBackOfficeTokensHandler
             return ValueTask.CompletedTask;
         }
 
-        if (TryGetCookie(GetHttpContext(), AccessTokenCookieName, out var accessToken))
+        if (TryGetCookie(GetHttpContext(), _accessTokenCookieName, out var accessToken))
         {
             context.AccessToken = accessToken;
         }
@@ -163,6 +228,7 @@ internal sealed class HideBackOfficeTokensHandler
         return ValueTask.CompletedTask;
     }
 
+    /// <inheritdoc/>
     public void Handle(UserLogoutSuccessNotification notification)
     {
         HttpContext? httpContext = _httpContextAccessor.HttpContext;
@@ -174,8 +240,8 @@ internal sealed class HideBackOfficeTokensHandler
             return;
         }
 
-        RemoveCookie(httpContext, AccessTokenCookieName);
-        RemoveCookie(httpContext, RefreshTokenCookieName);
+        RemoveCookie(httpContext, _accessTokenCookieName);
+        RemoveCookie(httpContext, _refreshTokenCookieName);
     }
 
     private HttpContext GetHttpContext()
@@ -231,8 +297,19 @@ internal sealed class HideBackOfficeTokensHandler
         var key = GetCookieKey(httpContext, cookieName);
         if (httpContext.Request.Cookies.TryGetValue(key, out var cookieValue))
         {
-            value = EncryptionHelper.Decrypt(cookieValue, _dataProtectionProvider);
-            return true;
+            try
+            {
+                value = EncryptionHelper.Decrypt(cookieValue, _dataProtectionProvider);
+                return true;
+            }
+            catch (CryptographicException ex)
+            {
+                // Decryption can fail if the data protection key ring has changed
+                // (e.g., after deployment, app pool recycle, or slot swap).
+                // Treat this as a missing cookie — the user will need to re-authenticate.
+                _logger.LogWarning(ex, "Failed to decrypt back-office token cookie '{CookieName}'. The user will need to re-authenticate.", cookieName);
+                RemoveCookie(httpContext, cookieName);
+            }
         }
 
         value = null;

src/Umbraco.Cms.Api.Common/DependencyInjection/MvcBuilderExtensions.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
@@ -6,8 +6,18 @@ using Umbraco.Cms.Api.Common.Configuration;
 
 namespace Umbraco.Cms.Api.Common.DependencyInjection;
 
+/// <summary>
+///     Extension methods for <see cref="IMvcBuilder"/>.
+/// </summary>
 public static class MvcBuilderExtensions
 {
+    /// <summary>
+    ///     Adds named JSON serialization options to the MVC builder.
+    /// </summary>
+    /// <param name="builder">The MVC builder.</param>
+    /// <param name="settingsName">The name for the JSON options configuration.</param>
+    /// <param name="configure">The action to configure the JSON options.</param>
+    /// <returns>The MVC builder for method chaining.</returns>
     public static IMvcBuilder AddJsonOptions(this IMvcBuilder builder, string settingsName, Action<JsonOptions> configure)
     {
         builder.Services.Configure(settingsName, configure);

src/Umbraco.Cms.Api.Common/DependencyInjection/OpenApiSchemaServiceExtensions.cs

@@ -0,0 +1,75 @@
+using Microsoft.AspNetCore.Http.Json;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace Umbraco.Cms.Api.Common.DependencyInjection;
+
+/// <summary>
+/// Extension methods for replacing the internal Microsoft.AspNetCore.OpenApi schema service registration.
+/// </summary>
+internal static class OpenApiSchemaServiceExtensions
+{
+    /// <summary>
+    /// The full name of the internal Microsoft type whose registration is replaced.
+    /// Used for a stringly-typed <see cref="ServiceDescriptor"/> lookup because the type is not publicly accessible.
+    /// </summary>
+    internal const string OpenApiSchemaServiceFullName = "Microsoft.AspNetCore.OpenApi.OpenApiSchemaService";
+
+    /// <summary>
+    /// Replaces the internal Microsoft <c>OpenApiSchemaService</c> registration for the specified document so that schema
+    /// generation uses the named <see cref="JsonOptions"/> rather than the default HTTP JSON options.
+    /// </summary>
+    /// <param name="services">The service collection.</param>
+    /// <param name="documentName">The OpenAPI document key (matches the keyed singleton registered by <c>AddOpenApi(documentName)</c>).</param>
+    /// <param name="jsonOptionsName">The named <see cref="JsonOptions"/> to use during schema generation for this document.</param>
+    /// <returns>The same <see cref="IServiceCollection"/> for chaining.</returns>
+    /// <remarks>
+    /// Workaround for <see href="https://github.com/dotnet/aspnetcore/issues/66340">dotnet/aspnetcore#66340</see>.
+    /// </remarks>
+    public static IServiceCollection ReplaceOpenApiSchemaService(
+        this IServiceCollection services,
+        string documentName,
+        string jsonOptionsName)
+        => services.ReplaceOpenApiSchemaService(
+            documentName,
+            sp => sp.GetRequiredService<IOptionsMonitor<JsonOptions>>().Get(jsonOptionsName));
+
+    /// <summary>
+    /// Replaces the internal Microsoft <c>OpenApiSchemaService</c> registration for the specified document so that schema
+    /// generation uses the <see cref="JsonOptions"/> instance produced by the supplied factory. Use this overload when
+    /// the options need to be resolved from the service provider, computed at the last moment, or built in a way that
+    /// doesn't fit the named-options lookup.
+    /// </summary>
+    /// <param name="services">The service collection.</param>
+    /// <param name="documentName">The OpenAPI document key.</param>
+    /// <param name="jsonOptionsFactory">Factory invoked when the schema service is first resolved. Receives the resolving <see cref="IServiceProvider"/> and returns the <see cref="JsonOptions"/> to use.</param>
+    /// <returns>The same <see cref="IServiceCollection"/> for chaining.</returns>
+    /// <remarks>
+    /// Workaround for <see href="https://github.com/dotnet/aspnetcore/issues/66340">dotnet/aspnetcore#66340</see>.
+    /// </remarks>
+    public static IServiceCollection ReplaceOpenApiSchemaService(
+        this IServiceCollection services,
+        string documentName,
+        Func<IServiceProvider, JsonOptions> jsonOptionsFactory)
+    {
+        ServiceDescriptor descriptor = services.FirstOrDefault(sd =>
+            sd.ServiceType.FullName == OpenApiSchemaServiceFullName
+            && Equals(sd.ServiceKey, documentName))
+            ?? throw new InvalidOperationException(
+                $"Could not find a registration for {OpenApiSchemaServiceFullName} keyed with '{documentName}'. "
+                + $"Ensure AddOpenApi(\"{documentName}\") has been called before {nameof(ReplaceOpenApiSchemaService)}, "
+                + "or check whether the internal Microsoft.AspNetCore.OpenApi registration shape has changed.");
+
+        services.Remove(descriptor);
+        services.AddKeyedSingleton(
+            descriptor.ServiceType,
+            documentName,
+            (sp, key) => ActivatorUtilities.CreateInstance(
+                sp,
+                descriptor.ServiceType,
+                key,
+                Options.Create(jsonOptionsFactory(sp))));
+
+        return services;
+    }
+}

src/Umbraco.Cms.Api.Common/DependencyInjection/OpenApiServiceCollectionExtensions.cs

@@ -0,0 +1,51 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Swashbuckle.AspNetCore.SwaggerUI;
+using Umbraco.Cms.Api.Common.OpenApi;
+using Umbraco.Extensions;
+
+namespace Umbraco.Cms.Api.Common.DependencyInjection;
+
+/// <summary>
+/// Extension methods for <see cref="IServiceCollection"/> to configure OpenAPI services.
+/// </summary>
+public static class OpenApiServiceCollectionExtensions
+{
+    /// <summary>
+    /// Adds an OpenAPI document to the OpenAPI UI document selector dropdown.
+    /// </summary>
+    /// <param name="services">The <see cref="IServiceCollection"/> instance.</param>
+    /// <param name="documentName">The name/identifier of the OpenAPI document.</param>
+    /// <param name="documentTitle">The title to display in the UI dropdown. Defaults to <paramref name="documentName"/> if not specified.</param>
+    /// <returns>The <see cref="IServiceCollection"/> instance.</returns>
+    public static IServiceCollection AddOpenApiDocumentToUi(
+        this IServiceCollection services,
+        string documentName,
+        string? documentTitle = null)
+        => services.AddOpenApiDocumentToUi(documentName, () => documentTitle);
+
+    /// <summary>
+    /// Adds an OpenAPI document to the OpenAPI UI document selector dropdown, resolving the title lazily so
+    /// callers (such as builder-pattern helpers) can defer it until SwaggerUI options are resolved.
+    /// </summary>
+    /// <param name="services">The <see cref="IServiceCollection"/> instance.</param>
+    /// <param name="documentName">The name/identifier of the OpenAPI document.</param>
+    /// <param name="documentTitleFactory">Factory invoked when SwaggerUI options are resolved. Returning <c>null</c> falls back to <paramref name="documentName"/>.</param>
+    /// <returns>The <see cref="IServiceCollection"/> instance.</returns>
+    internal static IServiceCollection AddOpenApiDocumentToUi(
+        this IServiceCollection services,
+        string documentName,
+        Func<string?> documentTitleFactory)
+    {
+        services.AddOptions<SwaggerUIOptions>()
+            .Configure<IOptions<UmbracoOpenApiOptions>>((swaggerUiOptions, openApiOptions) =>
+            {
+                var openApiRoute = openApiOptions.Value.RouteTemplate.Replace("{documentName}", documentName).EnsureStartsWith("/");
+                swaggerUiOptions.SwaggerEndpoint(openApiRoute, documentTitleFactory() ?? documentName);
+                swaggerUiOptions.ConfigObject.Urls = swaggerUiOptions.ConfigObject.Urls.OrderBy(x => x.Name);
+            });
+
+        return services;
+    }
+}

src/Umbraco.Cms.Api.Common/DependencyInjection/ProcessRequestContextHandler.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using OpenIddict.Server;
 using OpenIddict.Validation;
 using Umbraco.Cms.Core;
@@ -6,12 +6,23 @@ using Umbraco.Extensions;
 
 namespace Umbraco.Cms.Api.Common.DependencyInjection;
 
+/// <summary>
+///     Handles OpenIddict request processing to skip handling for non-authentication requests.
+/// </summary>
+/// <remarks>
+///     This handler prevents OpenIddict from processing every request to the server,
+///     limiting its scope to back-office and well-known OpenID Connect endpoints.
+/// </remarks>
 public class ProcessRequestContextHandler
     : IOpenIddictServerHandler<OpenIddictServerEvents.ProcessRequestContext>, IOpenIddictValidationHandler<OpenIddictValidationEvents.ProcessRequestContext>
 {
     private readonly IHttpContextAccessor _httpContextAccessor;
     private readonly string[] _pathsToHandle;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="ProcessRequestContextHandler"/> class.
+    /// </summary>
+    /// <param name="httpContextAccessor">The HTTP context accessor.</param>
     public ProcessRequestContextHandler(IHttpContextAccessor httpContextAccessor)
     {
         _httpContextAccessor = httpContextAccessor;
@@ -21,6 +32,11 @@ public class ProcessRequestContextHandler
         _pathsToHandle = [backOfficePathSegment, "/.well-known/openid-configuration", "/.well-known/jwks"];
     }
 
+    /// <summary>
+    ///     Handles the server process request context event.
+    /// </summary>
+    /// <param name="context">The process request context.</param>
+    /// <returns>A <see cref="ValueTask"/> representing the asynchronous operation.</returns>
     public ValueTask HandleAsync(OpenIddictServerEvents.ProcessRequestContext context)
     {
         if (SkipOpenIddictHandlingForRequest())
@@ -31,6 +47,11 @@ public class ProcessRequestContextHandler
         return ValueTask.CompletedTask;
     }
 
+    /// <summary>
+    ///     Handles the validation process request context event.
+    /// </summary>
+    /// <param name="context">The process request context.</param>
+    /// <returns>A <see cref="ValueTask"/> representing the asynchronous operation.</returns>
     public ValueTask HandleAsync(OpenIddictValidationEvents.ProcessRequestContext context)
     {
         if (SkipOpenIddictHandlingForRequest())

src/Umbraco.Cms.Api.Common/DependencyInjection/UmbracoBuilderApiExtensions.cs

@@ -1,33 +1,72 @@
+using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
 using Umbraco.Cms.Api.Common.Configuration;
 using Umbraco.Cms.Api.Common.OpenApi;
 using Umbraco.Cms.Api.Common.Serialization;
+using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.DependencyInjection;
+using Umbraco.Cms.Core.Hosting;
 using Umbraco.Cms.Web.Common.ApplicationBuilder;
+using IHostingEnvironment = Umbraco.Cms.Core.Hosting.IHostingEnvironment;
 
 namespace Umbraco.Cms.Api.Common.DependencyInjection;
 
+/// <summary>
+///     Extension methods for <see cref="IUmbracoBuilder"/> to configure API services.
+/// </summary>
 public static class UmbracoBuilderApiExtensions
 {
-    public static IUmbracoBuilder AddUmbracoApiOpenApiUI(this IUmbracoBuilder builder)
+    /// <summary>
+    ///     Adds Umbraco API OpenAPI/Swagger UI services to the builder.
+    /// </summary>
+    /// <param name="builder">The Umbraco builder.</param>
+    internal static void AddUmbracoOpenApi(this IUmbracoBuilder builder)
     {
-        if (builder.Services.Any(x => !x.IsKeyedService && x.ImplementationType == typeof(OperationIdSelector)))
+        if (builder.Services.Any(x => !x.IsKeyedService && x.ImplementationType == typeof(UmbracoJsonTypeInfoResolver)))
         {
-            return builder;
+            return;
         }
 
-        builder.Services.AddSwaggerGen();
-        builder.Services.ConfigureOptions<ConfigureUmbracoSwaggerGenOptions>();
+        builder.Services.AddOptions<UmbracoOpenApiOptions>()
+            .Configure<IHostingEnvironment, IWebHostEnvironment>((options, hostingEnv, webHostEnv) =>
+            {
+                options.Enabled = webHostEnv.IsProduction() is false;
+                var backOfficePath = hostingEnv.GetBackOfficePath().TrimStart(Constants.CharArrays.ForwardSlash);
+                options.RouteTemplate = $"{backOfficePath}/openapi/{{documentName}}.json";
+                options.UiRoutePrefix = $"{backOfficePath}/openapi";
+            });
+        builder.AddUmbracoOpenApiDocument<ConfigureDefaultApiOptions>(DefaultApiConfiguration.ApiName, "Default API");
         builder.Services.AddSingleton<IUmbracoJsonTypeInfoResolver, UmbracoJsonTypeInfoResolver>();
-        builder.Services.AddSingleton<IOperationIdSelector, OperationIdSelector>();
-        builder.Services.AddSingleton<IOperationIdHandler, OperationIdHandler>();
-        builder.Services.AddSingleton<ISchemaIdSelector, SchemaIdSelector>();
-        builder.Services.AddSingleton<ISchemaIdHandler, SchemaIdHandler>();
-        builder.Services.AddSingleton<ISubTypesSelector, SubTypesSelector>();
-        builder.Services.AddSingleton<ISubTypesHandler, SubTypesHandler>();
-        builder.Services.AddSingleton<IDocumentInclusionSelector, DocumentInclusionSelector>();
-        builder.Services.Configure<UmbracoPipelineOptions>(options => options.AddFilter(new SwaggerRouteTemplatePipelineFilter("UmbracoApiCommon")));
+        builder.Services.Configure<UmbracoPipelineOptions>(options => options.AddFilter(new OpenApiRouteTemplatePipelineFilter("UmbracoApiCommon")));
+    }
 
-        return builder;
+    /// <summary>
+    /// Adds and configures an Umbraco OpenAPI document with shared transformers.
+    /// </summary>
+    /// <param name="builder">The Umbraco builder.</param>
+    /// <param name="apiName">The name/identifier of the API.</param>
+    /// <param name="apiTitle">The title of the API.</param>
+    /// <param name="jsonOptionsName">
+    /// Optional named <c>JsonOptions</c> to use for schema generation instead of the default HTTP JSON options.
+    /// When specified, replaces the internal <c>OpenApiSchemaService</c> registration for this document.
+    /// </param>
+    /// <typeparam name="TConfigureOptions">The type used to configure the OpenAPI options.</typeparam>
+    internal static void AddUmbracoOpenApiDocument<TConfigureOptions>(
+        this IUmbracoBuilder builder,
+        string apiName,
+        string apiTitle,
+        string? jsonOptionsName = null)
+        where TConfigureOptions : ConfigureUmbracoOpenApiOptionsBase
+    {
+        apiName = apiName.ToLowerInvariant();
+        builder.Services.AddOpenApi(apiName);
+        builder.Services.ConfigureOptions<TConfigureOptions>();
+        builder.Services.AddOpenApiDocumentToUi(apiName, apiTitle);
+
+        if (jsonOptionsName is not null)
+        {
+            builder.Services.ReplaceOpenApiSchemaService(apiName, jsonOptionsName);
+        }
     }
 }

src/Umbraco.Cms.Api.Common/DependencyInjection/UmbracoBuilderAuthExtensions.cs

@@ -9,14 +9,26 @@ using Umbraco.Cms.Api.Common.Security;
 using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.Configuration.Models;
 using Umbraco.Cms.Core.DependencyInjection;
+using Umbraco.Cms.Core.Notifications;
 using Umbraco.Cms.Infrastructure.BackgroundJobs;
 using Umbraco.Cms.Infrastructure.BackgroundJobs.Jobs.DistributedJobs;
-using Umbraco.Cms.Core.Notifications;
 
 namespace Umbraco.Cms.Api.Common.DependencyInjection;
 
+/// <summary>
+///     Extension methods for <see cref="IUmbracoBuilder"/> to configure authentication services.
+/// </summary>
 public static class UmbracoBuilderAuthExtensions
 {
+    /// <summary>
+    ///     Adds OpenIddict authentication services for Umbraco APIs.
+    /// </summary>
+    /// <param name="builder">The Umbraco builder.</param>
+    /// <returns>The Umbraco builder for method chaining.</returns>
+    /// <remarks>
+    ///     Configures OpenIddict with authorization code flow (with PKCE), client credentials flow,
+    ///     reference tokens, and ASP.NET Core Data Protection for token encryption.
+    /// </remarks>
     public static IUmbracoBuilder AddUmbracoOpenIddict(this IUmbracoBuilder builder)
     {
         if (builder.Services.Any(x => !x.IsKeyedService && x.ImplementationType == typeof(OpenIddictCleanupJob)) is false)
@@ -133,6 +145,12 @@ public static class UmbracoBuilderAuthExtensions
                         .UseSingletonHandler<HideBackOfficeTokensHandler>()
                         .SetOrder(OpenIddict.Server.AspNetCore.OpenIddictServerAspNetCoreHandlers.ExtractPostRequest<OpenIddictServerEvents.ExtractTokenRequestContext>.Descriptor.Order + 1);
                 });
+                options.AddEventHandler<OpenIddictServerEvents.ExtractRevocationRequestContext>(configuration =>
+                {
+                    configuration
+                        .UseSingletonHandler<HideBackOfficeTokensHandler>()
+                        .SetOrder(OpenIddict.Server.AspNetCore.OpenIddictServerAspNetCoreHandlers.ExtractPostRequest<OpenIddictServerEvents.ExtractRevocationRequestContext>.Descriptor.Order + 1);
+                });
             })
 
             // Register the OpenIddict validation components.

src/Umbraco.Cms.Api.Common/Extensions/ActionDescriptorApiCommonExtensions.cs

@@ -33,4 +33,4 @@ public static class ActionDescriptorApiCommonExtensions
 
         return mapToApiAttributes.SingleOrDefault()?.ApiName;
     }
-}
+}

src/Umbraco.Cms.Api.Common/Extensions/MethodInfoApiCommonExtensions.cs

@@ -5,9 +5,16 @@ using Umbraco.Cms.Api.Common.Configuration;
 
 namespace Umbraco.Extensions;
 
+/// <summary>
+///     Extension methods for <see cref="MethodInfo"/> to work with API-related attributes.
+/// </summary>
 public static class MethodInfoApiCommonExtensions
 {
-
+    /// <summary>
+    ///     Gets the API version values from <see cref="MapToApiVersionAttribute"/> applied to the method.
+    /// </summary>
+    /// <param name="methodInfo">The method info to inspect.</param>
+    /// <returns>A pipe-separated string of API version values.</returns>
     public static string GetMapToApiVersionAttributeValue(this MethodInfo methodInfo)
     {
         MapToApiVersionAttribute[] mapToApis = methodInfo.GetCustomAttributes(typeof(MapToApiVersionAttribute), inherit: true).Cast<MapToApiVersionAttribute>().ToArray();
@@ -15,6 +22,11 @@ public static class MethodInfoApiCommonExtensions
         return string.Join("|", mapToApis.SelectMany(x => x.Versions));
     }
 
+    /// <summary>
+    ///     Gets the API name from <see cref="MapToApiAttribute"/> applied to the method's declaring type.
+    /// </summary>
+    /// <param name="methodInfo">The method info to inspect.</param>
+    /// <returns>The API name if the attribute is present; otherwise, <c>null</c>.</returns>
     public static string? GetMapToApiAttributeValue(this MethodInfo methodInfo)
     {
         MapToApiAttribute[] mapToApis = (methodInfo.DeclaringType?.GetCustomAttributes(typeof(MapToApiAttribute), inherit: true) ?? Array.Empty<object>()).Cast<MapToApiAttribute>().ToArray();
@@ -22,6 +34,15 @@ public static class MethodInfoApiCommonExtensions
         return mapToApis.SingleOrDefault()?.ApiName;
     }
 
+    /// <summary>
+    ///     Determines whether the method's declaring type has a <see cref="MapToApiAttribute"/> with the specified API name.
+    /// </summary>
+    /// <param name="methodInfo">The method info to inspect.</param>
+    /// <param name="apiName">The API name to check for.</param>
+    /// <returns>
+    ///     <c>true</c> if the attribute is present and matches the specified API name,
+    ///     or if the attribute is not present and the API name matches the default API name; otherwise, <c>false</c>.
+    /// </returns>
     public static bool HasMapToApiAttribute(this MethodInfo methodInfo, string apiName)
     {
         var value = methodInfo.GetMapToApiAttributeValue();

src/Umbraco.Cms.Api.Common/Filters/JsonOptionsNameAttribute.cs

@@ -1,9 +1,19 @@
-namespace Umbraco.Cms.Api.Common.Filters;
+namespace Umbraco.Cms.Api.Common.Filters;
 
+/// <summary>
+///     Attribute used to specify the named JSON serialization options for a controller.
+/// </summary>
 [AttributeUsage(AttributeTargets.Class)]
 public class JsonOptionsNameAttribute : Attribute
 {
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="JsonOptionsNameAttribute"/> class.
+    /// </summary>
+    /// <param name="jsonOptionsName">The name of the JSON options configuration to use.</param>
     public JsonOptionsNameAttribute(string jsonOptionsName) => JsonOptionsName = jsonOptionsName;
 
+    /// <summary>
+    ///     Gets the name of the JSON options configuration.
+    /// </summary>
     public string JsonOptionsName { get; }
 }

src/Umbraco.Cms.Api.Common/Json/HttpContextJsonExtensions.cs

@@ -1,10 +1,18 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Umbraco.Cms.Api.Common.Filters;
 
 namespace Umbraco.Cms.Api.Common.Json;
 
+/// <summary>
+///     Extension methods for <see cref="HttpContext"/> related to JSON serialization.
+/// </summary>
 public static class HttpContextJsonExtensions
 {
+    /// <summary>
+    ///     Gets the named JSON options configuration for the current endpoint.
+    /// </summary>
+    /// <param name="context">The HTTP context.</param>
+    /// <returns>The JSON options name if specified via <see cref="JsonOptionsNameAttribute"/>; otherwise, <c>null</c>.</returns>
     public static string? CurrentJsonOptionsName(this HttpContext context)
         => context.GetEndpoint()?.Metadata.GetMetadata<JsonOptionsNameAttribute>()?.JsonOptionsName;
 }

src/Umbraco.Cms.Api.Common/Json/NamedSystemTextJsonInputFormatter.cs

@@ -1,20 +1,31 @@
-using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.Extensions.Logging;
 
 namespace Umbraco.Cms.Api.Common.Json;
 
+/// <summary>
+///     A JSON input formatter that only processes requests for endpoints with matching named JSON options.
+/// </summary>
 internal sealed class NamedSystemTextJsonInputFormatter : SystemTextJsonInputFormatter
 {
     private readonly string _jsonOptionsName;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="NamedSystemTextJsonInputFormatter"/> class.
+    /// </summary>
+    /// <param name="jsonOptionsName">The name of the JSON options configuration this formatter handles.</param>
+    /// <param name="options">The JSON options.</param>
+    /// <param name="logger">The logger.</param>
     public NamedSystemTextJsonInputFormatter(string jsonOptionsName, JsonOptions options, ILogger<NamedSystemTextJsonInputFormatter> logger)
         : base(options, logger) =>
         _jsonOptionsName = jsonOptionsName;
 
+    /// <inheritdoc/>
     public override bool CanRead(InputFormatterContext context)
         => context.HttpContext.CurrentJsonOptionsName() == _jsonOptionsName && base.CanRead(context);
 
+    /// <inheritdoc/>
     public override async Task<InputFormatterResult> ReadAsync(InputFormatterContext context)
     {
         try

src/Umbraco.Cms.Api.Common/Json/NamedSystemTextJsonOutputFormatter.cs

@@ -1,17 +1,26 @@
-using System.Text.Json;
+using System.Text.Json;
 using Microsoft.AspNetCore.Mvc.Formatters;
 
 namespace Umbraco.Cms.Api.Common.Json;
 
+/// <summary>
+///     A JSON output formatter that only processes responses for endpoints with matching named JSON options.
+/// </summary>
 internal sealed class NamedSystemTextJsonOutputFormatter : SystemTextJsonOutputFormatter
 {
     private readonly string _jsonOptionsName;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="NamedSystemTextJsonOutputFormatter"/> class.
+    /// </summary>
+    /// <param name="jsonOptionsName">The name of the JSON options configuration this formatter handles.</param>
+    /// <param name="jsonSerializerOptions">The JSON serializer options.</param>
     public NamedSystemTextJsonOutputFormatter(string jsonOptionsName, JsonSerializerOptions jsonSerializerOptions) : base(jsonSerializerOptions)
     {
         _jsonOptionsName = jsonOptionsName;
     }
 
+    /// <inheritdoc/>
     public override bool CanWriteResult(OutputFormatterCanWriteContext context)
         => context.HttpContext.CurrentJsonOptionsName() == _jsonOptionsName && base.CanWriteResult(context);
 }

src/Umbraco.Cms.Api.Common/Mvc/ActionResults/EmptyCreatedAtActionResult.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Routing;
 using Microsoft.Extensions.DependencyInjection;
@@ -16,6 +16,13 @@ public sealed class EmptyCreatedAtActionResult : ActionResult
     private readonly object _routeValues;
     private readonly string _resourceIdentifier;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="EmptyCreatedAtActionResult"/> class.
+    /// </summary>
+    /// <param name="actionName">The name of the action to generate the URL for.</param>
+    /// <param name="controllerName">The name of the controller to generate the URL for.</param>
+    /// <param name="routeValues">The route values to use for URL generation.</param>
+    /// <param name="resourceIdentifier">The identifier of the created resource.</param>
     public EmptyCreatedAtActionResult(string actionName, string controllerName, object routeValues, string resourceIdentifier)
     {
         _actionName = actionName;
@@ -24,6 +31,7 @@ public sealed class EmptyCreatedAtActionResult : ActionResult
         _resourceIdentifier = resourceIdentifier;
     }
 
+    /// <inheritdoc/>
     public override void ExecuteResult(ActionContext context)
     {
         ArgumentNullException.ThrowIfNull(context);

src/Umbraco.Cms.Api.Common/OpenApi/BackOfficeOpenApiDocumentBuilder.cs

@@ -0,0 +1,177 @@
+using Microsoft.AspNetCore.Http.Json;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Umbraco.Cms.Api.Common.Attributes;
+using Umbraco.Cms.Api.Common.DependencyInjection;
+using Umbraco.Cms.Core.DependencyInjection;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Fluent builder for configuring a custom OpenAPI document.
+/// </summary>
+public sealed class BackOfficeOpenApiDocumentBuilder
+{
+    private readonly List<Action<OpenApiOptions>> _configurations = [];
+
+    private string? _title;
+    private string? _uiTitle;
+    private bool _includedInUi = true;
+    private Func<IServiceProvider, JsonOptions>? _httpJsonOptionsFactory;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="BackOfficeOpenApiDocumentBuilder"/> class.
+    /// </summary>
+    /// <param name="documentName">The name of the OpenAPI document being configured.</param>
+    internal BackOfficeOpenApiDocumentBuilder(string documentName)
+        => DocumentName = documentName;
+
+    /// <summary>
+    /// Gets the name of the OpenAPI document being configured.
+    /// </summary>
+    public string DocumentName { get; }
+
+    /// <summary>
+    /// Sets the document's <c>Info.Title</c>. Also used as the UI dropdown label unless overridden via
+    /// <see cref="WithUiTitle"/>.
+    /// </summary>
+    /// <param name="title">The title to display.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder WithTitle(string title)
+    {
+        _title = title;
+        return this;
+    }
+
+    /// <summary>
+    /// Overrides the UI dropdown label for this document.
+    /// </summary>
+    /// <param name="uiTitle">The label to display.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder WithUiTitle(string uiTitle)
+    {
+        _uiTitle = uiTitle;
+        return this;
+    }
+
+    /// <summary>
+    /// Excludes this document from the UI dropdown.
+    /// </summary>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder ExcludeFromUi()
+    {
+        _includedInUi = false;
+        return this;
+    }
+
+    /// <summary>
+    /// Adds an <see cref="OpenApiOptions"/> configuration callback. Multiple calls compose.
+    /// </summary>
+    /// <param name="configure">Callback to configure the options.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder ConfigureOpenApiOptions(Action<OpenApiOptions> configure)
+    {
+        _configurations.Add(configure);
+        return this;
+    }
+
+    /// <summary>
+    /// Sets the named <see cref="JsonOptions">Microsoft.AspNetCore.Http.Json.JsonOptions</see> used when
+    /// generating this document's schema. Use this to match the serialization conventions of the API
+    /// endpoints the document describes.
+    /// </summary>
+    /// <param name="jsonOptionsName">The name of the registered HTTP <see cref="JsonOptions"/> to apply.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder WithJsonOptions(string jsonOptionsName)
+        => WithJsonOptions(sp => sp.GetRequiredService<IOptionsMonitor<JsonOptions>>().Get(jsonOptionsName));
+
+    /// <summary>
+    /// Sets the <see cref="JsonOptions">Microsoft.AspNetCore.Http.Json.JsonOptions</see> used when
+    /// generating this document's schema. Use this to match the serialization conventions of the API
+    /// endpoints the document describes.
+    /// </summary>
+    /// <param name="jsonOptions">The HTTP JSON options to apply.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder WithJsonOptions(JsonOptions jsonOptions)
+        => WithJsonOptions(_ => jsonOptions);
+
+    /// <summary>
+    /// Sets a factory that produces the <see cref="JsonOptions">Microsoft.AspNetCore.Http.Json.JsonOptions</see>
+    /// used when generating this document's schema. Use this to match the serialization conventions of the
+    /// API endpoints the document describes.
+    /// </summary>
+    /// <param name="jsonOptionsFactory">Factory invoked when the schema service is first resolved.</param>
+    /// <returns>The same builder for chaining.</returns>
+    public BackOfficeOpenApiDocumentBuilder WithJsonOptions(Func<IServiceProvider, JsonOptions> jsonOptionsFactory)
+    {
+        _httpJsonOptionsFactory = jsonOptionsFactory;
+        return this;
+    }
+
+    /// <summary>
+    /// Applies the accumulated configuration to the supplied <see cref="IUmbracoBuilder"/>'s service
+    /// collection. Called by <c>AddBackOfficeOpenApiDocument</c> once the user-supplied callback returns.
+    /// </summary>
+    /// <param name="builder">The Umbraco builder to register services against.</param>
+    internal void Build(IUmbracoBuilder builder)
+    {
+        // AddOpenApi lowercases the document name when registering its keyed services (https://github.com/dotnet/aspnetcore/blob/v10.0.9/src/OpenApi/src/Extensions/OpenApiServiceCollectionExtensions.cs#L64),
+        // so we must normalise here to keep AddOpenApiDocumentToUi and ReplaceOpenApiSchemaService in sync.
+        string lowercasedDocumentName = DocumentName.ToLowerInvariant();
+
+        builder.Services.AddOpenApi(
+            lowercasedDocumentName,
+            options =>
+            {
+                // ShouldInclude matches [MapToApi] case-insensitively to align with how documents are registered.
+                options.ShouldInclude = apiDescription =>
+                    apiDescription.ActionDescriptor.EndpointMetadata
+                        ?.OfType<MapToApiAttribute>()
+                        .Any(a => a.ApiName.Equals(DocumentName, StringComparison.OrdinalIgnoreCase))
+                    ?? false;
+
+                options.CreateSchemaReferenceId = UmbracoSchemaIdGenerator.CreateSchemaReferenceId;
+
+                if (_title is not null)
+                {
+                    options.AddDocumentTransformer((document, _, _) =>
+                    {
+                        document.Info.Title = _title;
+                        return Task.CompletedTask;
+                    });
+                }
+
+                // Generate operation IDs using Umbraco's naming conventions.
+                options.AddOperationTransformer<UmbracoOperationIdTransformer>();
+
+                // Trim redundant JSON-equivalent MIME types (e.g. text/json, application/*+json, text/plain)
+                // that ASP.NET Core adds alongside application/json.
+                options.AddOperationTransformer<MimeTypesTransformer>();
+
+                // Mark non-nullable properties as required so generated SDKs reflect the C# nullability.
+                options.AddSchemaTransformer<RequireNonNullablePropertiesSchemaTransformer>();
+
+                // Tag actions by group name and cleanup unused tags (caused by the tag changes).
+                options
+                    .AddOperationTransformer<TagActionsByGroupNameTransformer>()
+                    .AddDocumentTransformer<TagActionsByGroupNameTransformer>()
+                    .AddDocumentTransformer<SortTagsAndPathsTransformer>();
+
+                foreach (Action<OpenApiOptions> configure in _configurations)
+                {
+                    configure(options);
+                }
+            });
+
+        if (_includedInUi)
+        {
+            builder.Services.AddOpenApiDocumentToUi(lowercasedDocumentName, _uiTitle ?? _title ?? DocumentName);
+        }
+
+        if (_httpJsonOptionsFactory is not null)
+        {
+            builder.Services.ReplaceOpenApiSchemaService(lowercasedDocumentName, _httpJsonOptionsFactory);
+        }
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/DocumentInclusionSelector.cs

@@ -1,30 +0,0 @@
-using Asp.Versioning;
-using Microsoft.AspNetCore.Mvc.Abstractions;
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-using Microsoft.AspNetCore.Mvc.Controllers;
-using Umbraco.Cms.Api.Common.Configuration;
-using Umbraco.Extensions;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-/// <summary>
-/// Determines whether an API description should be included in a specific documentation set based on the document name
-/// and API metadata.
-/// </summary>
-public class DocumentInclusionSelector : IDocumentInclusionSelector
-{
-    /// <inheritdoc/>
-    public bool Include(string documentName, ApiDescription apiDescription)
-    {
-        if (apiDescription.ActionDescriptor is ControllerActionDescriptor controllerActionDescriptor
-            && controllerActionDescriptor.HasMapToApiAttribute(documentName))
-        {
-            return true;
-        }
-
-        ApiVersionMetadata apiVersionMetadata = apiDescription.ActionDescriptor.GetApiVersionMetadata();
-        return apiVersionMetadata.Name == documentName
-               || (string.IsNullOrEmpty(apiVersionMetadata.Name) && documentName == DefaultApiConfiguration.ApiName);
-    }
-}
-

src/Umbraco.Cms.Api.Common/OpenApi/EnumSchemaFilter.cs

@@ -1,27 +0,0 @@
-using System.Reflection;
-using System.Runtime.Serialization;
-using System.Text.Json.Nodes;
-using Microsoft.OpenApi;
-using Swashbuckle.AspNetCore.SwaggerGen;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class EnumSchemaFilter : ISchemaFilter
-{
-    public void Apply(IOpenApiSchema model, SchemaFilterContext context)
-    {
-        if (model is not OpenApiSchema schema || context.Type.IsEnum is false)
-        {
-            return;
-        }
-
-        schema.Type = JsonSchemaType.String;
-        schema.Format = null;
-        schema.Enum = new List<JsonNode>();
-        foreach (var name in Enum.GetNames(context.Type))
-        {
-            var actualName = context.Type.GetField(name)?.GetCustomAttribute<EnumMemberAttribute>()?.Value ?? name;
-            schema.Enum.Add(actualName);
-        }
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/ExcludeFromDefaultOpenApiDocumentAttribute.cs

@@ -0,0 +1,10 @@
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Excludes the controller from the default OpenAPI document.
+/// Use this when you have a custom OpenAPI document for your API.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class)]
+public sealed class ExcludeFromDefaultOpenApiDocumentAttribute : Attribute
+{
+}

src/Umbraco.Cms.Api.Common/OpenApi/FixFileReturnTypesTransformer.cs

@@ -0,0 +1,47 @@
+using System.IO.Pipelines;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Transformer to fix file return types in OpenAPI schema.
+/// </summary>
+/// <remarks>Can be removed once https://github.com/dotnet/aspnetcore/pull/63504 and
+/// https://github.com/dotnet/aspnetcore/pull/64562 are released.</remarks>
+internal class FixFileReturnTypesTransformer : IOpenApiSchemaTransformer
+{
+    private static readonly Type[] _binaryStringTypes =
+    [
+        typeof(IFormFile),
+        typeof(FileResult),
+        typeof(Stream),
+        typeof(PipeReader),
+    ];
+
+    /// <inheritdoc />
+    public Task TransformAsync(
+        OpenApiSchema schema,
+        OpenApiSchemaTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        if (_binaryStringTypes.Any(possibleBaseType => possibleBaseType.IsAssignableFrom(context.JsonTypeInfo.Type)) is false)
+        {
+            return Task.CompletedTask;
+        }
+
+        // Clear all properties
+        schema.Properties?.Clear();
+        schema.Required?.Clear();
+
+        // Make it an inline schema
+        schema.Metadata?.Remove("x-schema-id");
+
+        // Set type to string with binary format
+        schema.Type = JsonSchemaType.String;
+        schema.Format = "binary";
+        return Task.CompletedTask;
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/IDocumentInclusionSelector.cs

@@ -1,19 +0,0 @@
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-/// <summary>
-/// Defines a method that determines whether a given API description should be included in a specific documentation
-/// document.
-/// </summary>
-public interface IDocumentInclusionSelector
-{
-    /// <summary>
-    /// Determines whether the specified API description should be included in the generated documentation for the given
-    /// document name.
-    /// </summary>
-    /// <param name="documentName">The name of the documentation document being generated.</param>
-    /// <param name="apiDescription">The API description to evaluate for inclusion.</param>
-    /// <returns>true if the API description should be included in the documentation; otherwise, false.</returns>
-    bool Include(string documentName, ApiDescription apiDescription);
-}

src/Umbraco.Cms.Api.Common/OpenApi/IOperationIdHandler.cs

@@ -1,10 +0,0 @@
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface IOperationIdHandler
-{
-     bool CanHandle(ApiDescription apiDescription);
-
-     string Handle(ApiDescription apiDescription);
-}

src/Umbraco.Cms.Api.Common/OpenApi/IOperationIdSelector.cs

@@ -1,9 +0,0 @@
-using Asp.Versioning;
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface IOperationIdSelector
-{
-    string? OperationId(ApiDescription apiDescription);
-}

src/Umbraco.Cms.Api.Common/OpenApi/ISchemaIdHandler.cs

@@ -1,8 +0,0 @@
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface ISchemaIdHandler
-{
-    bool CanHandle(Type type);
-
-    string Handle(Type type);
-}

src/Umbraco.Cms.Api.Common/OpenApi/ISchemaIdSelector.cs

@@ -1,6 +0,0 @@
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface ISchemaIdSelector
-{
-    string SchemaId(Type type);
-}

src/Umbraco.Cms.Api.Common/OpenApi/ISubTypesHandler.cs

@@ -1,8 +0,0 @@
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface ISubTypesHandler
-{
-    bool CanHandle(Type type, string documentName);
-
-    IEnumerable<Type> Handle(Type type);
-}

src/Umbraco.Cms.Api.Common/OpenApi/ISubTypesSelector.cs

@@ -1,6 +0,0 @@
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public interface ISubTypesSelector
-{
-    IEnumerable<Type> SubTypes(Type type);
-}

src/Umbraco.Cms.Api.Common/OpenApi/MimeTypeDocumentFilter.cs

@@ -1,55 +0,0 @@
-using Microsoft.OpenApi;
-using Swashbuckle.AspNetCore.SwaggerGen;
-using Umbraco.Extensions;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-/// <summary>
-/// This filter explicitly removes all other mime types than application/json from a named OpenAPI document when application/json is accepted.
-/// </summary>
-public class MimeTypeDocumentFilter : IDocumentFilter
-{
-    private readonly string _documentName;
-
-    public MimeTypeDocumentFilter(string documentName) => _documentName = documentName;
-
-    public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
-    {
-        if (context.DocumentName != _documentName)
-        {
-            return;
-        }
-
-        OpenApiOperation[] operations = swaggerDoc.Paths
-            .SelectMany(path => path.Value.Operations?.Values ?? Enumerable.Empty<OpenApiOperation>())
-            .ToArray();
-
-        void RemoveUnwantedMimeTypes(IDictionary<string, OpenApiMediaType>? content)
-        {
-            if (content is null || content.ContainsKey("application/json") is false)
-            {
-                return;
-            }
-
-            content.RemoveAll(r => r.Key != "application/json");
-        }
-
-        OpenApiRequestBody[] requestBodies = operations
-            .Select(operation => operation.RequestBody)
-            .OfType<OpenApiRequestBody>()
-            .ToArray();
-        foreach (OpenApiRequestBody requestBody in requestBodies)
-        {
-            RemoveUnwantedMimeTypes(requestBody.Content);
-        }
-
-        OpenApiResponse[] responses = operations
-            .SelectMany(operation => operation.Responses?.Values ?? Enumerable.Empty<IOpenApiResponse>())
-            .OfType<OpenApiResponse>()
-            .ToArray();
-        foreach (OpenApiResponse response in responses)
-        {
-            RemoveUnwantedMimeTypes(response.Content);
-        }
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/MimeTypesTransformer.cs

@@ -0,0 +1,88 @@
+using System.Net.Mime;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi;
+using Umbraco.Extensions;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Trims redundant JSON-equivalent media types from OpenAPI operations.
+/// </summary>
+/// <remarks>
+/// <para>
+/// ASP.NET Core's content negotiation populates operations with several media types that all serialize to JSON
+/// (<c>text/json</c>, <c>application/*+json</c>, and <c>text/plain</c> alongside <c>application/json</c>).
+/// When <c>application/json</c> is present on a response or request body, this transformer strips those
+/// equivalents so OpenAPI consumers and generated SDKs aren't burdened with variants that produce identical
+/// payloads. Non-JSON media types (e.g. <c>application/xml</c>, <c>application/octet-stream</c>) are preserved.
+/// </para>
+/// <para>
+/// Request bodies additionally honour <c>[Consumes]</c>: when the attribute is present, the request content is
+/// replaced entirely with the declared content types, taking precedence over the
+/// JSON-equivalent stripping above.
+/// </para>
+/// </remarks>
+internal class MimeTypesTransformer : IOpenApiOperationTransformer
+{
+    private static readonly string[] _jsonEquivalentMimeTypes =
+    [
+        MediaTypeNames.Text.Plain,
+        "application/*+json",
+        "text/json"
+    ];
+
+    /// <inheritdoc/>
+    public Task TransformAsync(
+        OpenApiOperation operation,
+        OpenApiOperationTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        // For request bodies, keep only the content types declared in [Consumes], or fall back to application/json.
+        if (operation.RequestBody?.Content is { } requestContent)
+        {
+            var explicitContentTypes = context.Description.ActionDescriptor.EndpointMetadata
+                .OfType<ConsumesAttribute>()
+                .SelectMany(p => p.ContentTypes)
+                .Distinct()
+                .ToArray();
+
+            if (explicitContentTypes.Length != 0)
+            {
+                // Replace content types entirely with what [Consumes] declares,
+                // preserving the schema from the existing entry.
+                OpenApiMediaType? existingMediaType = requestContent.Values.FirstOrDefault();
+                requestContent.Clear();
+                foreach (var contentType in explicitContentTypes)
+                {
+                    requestContent[contentType] = existingMediaType ?? new OpenApiMediaType();
+                }
+            }
+            else
+            {
+                RemoveJsonEquivalentMimeTypes(requestContent);
+            }
+        }
+
+        // For responses, drop JSON-equivalent media types when application/json is present.
+        foreach (IOpenApiResponse response in (operation.Responses ?? []).Values)
+        {
+            if (response is OpenApiResponse openApiResponse)
+            {
+                RemoveJsonEquivalentMimeTypes(openApiResponse.Content);
+            }
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private static void RemoveJsonEquivalentMimeTypes(IDictionary<string, OpenApiMediaType>? content)
+    {
+        if (content?.ContainsKey(MediaTypeNames.Application.Json) != true)
+        {
+            return;
+        }
+
+        content.RemoveAll(r => _jsonEquivalentMimeTypes.Contains(r.Key, StringComparer.OrdinalIgnoreCase));
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/OpenApiRouteTemplatePipelineFilter.cs

@@ -0,0 +1,57 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Swashbuckle.AspNetCore.SwaggerUI;
+using Umbraco.Cms.Core;
+using Umbraco.Cms.Web.Common.ApplicationBuilder;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+internal class OpenApiRouteTemplatePipelineFilter : UmbracoPipelineFilter
+{
+    public OpenApiRouteTemplatePipelineFilter(string name)
+        : base(name)
+    {
+        PostPipeline = PostPipelineAction;
+        PreMapEndpoints = OnPreMapEndpointsAction;
+    }
+
+    private static void PostPipelineAction(IApplicationBuilder applicationBuilder)
+    {
+        UmbracoOpenApiOptions options = applicationBuilder.ApplicationServices
+            .GetRequiredService<IOptions<UmbracoOpenApiOptions>>().Value;
+
+        if (options.Enabled is false || options.DefaultUiEnabled is false)
+        {
+            return;
+        }
+
+        applicationBuilder.UseSwaggerUI(swaggerUiOptions => ConfigureSwaggerUi(swaggerUiOptions, options));
+    }
+
+    private static void OnPreMapEndpointsAction(IEndpointRouteBuilder endpoints)
+    {
+        UmbracoOpenApiOptions options = endpoints.ServiceProvider
+            .GetRequiredService<IOptions<UmbracoOpenApiOptions>>().Value;
+
+        if (options.Enabled is false)
+        {
+            return;
+        }
+
+        endpoints.MapOpenApi(options.RouteTemplate);
+    }
+
+    private static void ConfigureSwaggerUi(SwaggerUIOptions swaggerUiOptions, UmbracoOpenApiOptions options)
+    {
+        swaggerUiOptions.RoutePrefix = options.UiRoutePrefix;
+
+        // Add custom configuration from https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/
+        swaggerUiOptions.ConfigObject.PersistAuthorization = true; // persists authorization data so it would not be lost on browser close/refresh
+        swaggerUiOptions.ConfigObject.Filter = string.Empty; // Enable the filter with an empty string as default filter.
+
+        swaggerUiOptions.OAuthClientId(Constants.OAuthClientIds.OpenApiUi);
+        swaggerUiOptions.OAuthUsePkce();
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/OperationIdHandler.cs

@@ -1,94 +0,0 @@
-using Asp.Versioning;
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-using Microsoft.AspNetCore.Mvc.Controllers;
-using Microsoft.Extensions.Options;
-using Umbraco.Extensions;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-// NOTE: Left unsealed on purpose, so it is extendable.
-public class OperationIdHandler : IOperationIdHandler
-{
-    private readonly ApiVersioningOptions _apiVersioningOptions;
-
-    public OperationIdHandler(IOptions<ApiVersioningOptions> apiVersioningOptions)
-        => _apiVersioningOptions = apiVersioningOptions.Value;
-
-    public bool CanHandle(ApiDescription apiDescription)
-    {
-        if (apiDescription.ActionDescriptor is not ControllerActionDescriptor controllerActionDescriptor)
-        {
-            return false;
-        }
-
-        return CanHandle(apiDescription, controllerActionDescriptor);
-    }
-
-    protected virtual bool CanHandle(ApiDescription apiDescription, ControllerActionDescriptor controllerActionDescriptor)
-        => controllerActionDescriptor.ControllerTypeInfo.Namespace?.StartsWith("Umbraco.Cms.Api") is true;
-
-    public virtual string Handle(ApiDescription apiDescription)
-        => UmbracoOperationId(apiDescription);
-
-    /// <summary>
-    ///     Generates a unique operation identifier for a given API following Umbraco's operation id naming conventions.
-    /// </summary>
-    protected string UmbracoOperationId(ApiDescription apiDescription)
-    {
-        if (apiDescription.ActionDescriptor is not ControllerActionDescriptor controllerActionDescriptor)
-        {
-            throw new ArgumentException($"This handler operates only on {nameof(ControllerActionDescriptor)}.");
-        }
-
-        ApiVersion defaultVersion = _apiVersioningOptions.DefaultApiVersion;
-        var httpMethod = apiDescription.HttpMethod?.ToLower().ToFirstUpper() ?? "Get";
-
-        // if the route info "Name" is supplied we'll use this explicitly as the operation ID
-        // - usage example: [HttpGet("my-api/route}", Name = "MyCustomRoute")]
-        if (string.IsNullOrWhiteSpace(apiDescription.ActionDescriptor.AttributeRouteInfo?.Name) == false)
-        {
-            var explicitOperationId = apiDescription.ActionDescriptor.AttributeRouteInfo!.Name;
-            return explicitOperationId.InvariantStartsWith(httpMethod)
-                ? explicitOperationId
-                : $"{httpMethod}{explicitOperationId}";
-        }
-
-        var relativePath = apiDescription.RelativePath;
-
-        if (string.IsNullOrWhiteSpace(relativePath))
-        {
-            throw new InvalidOperationException(
-                $"There is no relative path for controller action {apiDescription.ActionDescriptor.RouteValues["controller"]}");
-        }
-
-        // Remove the prefixed base path with version, e.g. /umbraco/management/api/v1/tracked-reference/{id} => tracked-reference/{id}
-        var unprefixedRelativePath = OperationIdRegexes
-            .VersionPrefixRegex()
-            .Replace(relativePath, string.Empty);
-
-        // Remove template placeholders, e.g. tracked-reference/{id} => tracked-reference/Id
-        var formattedOperationId = OperationIdRegexes
-            .TemplatePlaceholdersRegex()
-            .Replace(unprefixedRelativePath, m => $"By{m.Groups[1].Value.ToFirstUpper()}");
-
-        // Remove dashes (-) and slashes (/) and convert the following letter to uppercase with
-        // the word "By" in front, e.g. tracked-reference/Id => TrackedReferenceById
-        formattedOperationId = OperationIdRegexes
-            .ToCamelCaseRegex()
-            .Replace(formattedOperationId, m => m.Groups[1].Value.ToUpper());
-
-        // Get map to version attribute
-        string? version = null;
-
-        var versionAttributeValue = controllerActionDescriptor.MethodInfo.GetMapToApiVersionAttributeValue();
-
-        // We only want to add a version, if it is not the default one.
-        if (string.Equals(versionAttributeValue, defaultVersion.ToString()) == false)
-        {
-            version = versionAttributeValue;
-        }
-
-        // Return the operation ID with the formatted http method verb in front, e.g. GetTrackedReferenceById
-        return $"{httpMethod}{formattedOperationId.ToFirstUpper()}{version}";
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/OperationIdRegexes.cs

@@ -1,4 +1,4 @@
-using System.Text.RegularExpressions;
+using System.Text.RegularExpressions;
 
 namespace Umbraco.Cms.Api.Common.OpenApi;
 

src/Umbraco.Cms.Api.Common/OpenApi/OperationIdSelector.cs

@@ -1,24 +0,0 @@
-using Asp.Versioning;
-using Microsoft.AspNetCore.Mvc.ApiExplorer;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class OperationIdSelector : IOperationIdSelector
-{
-    private readonly IEnumerable<IOperationIdHandler> _operationIdHandlers;
-
-    [Obsolete("Use non-obsolete constructor. This will be removed in Umbraco 15.")]
-    public OperationIdSelector()
-        : this(Enumerable.Empty<IOperationIdHandler>())
-    {
-    }
-
-    public OperationIdSelector(IEnumerable<IOperationIdHandler> operationIdHandlers)
-        => _operationIdHandlers = operationIdHandlers;
-
-    public virtual string? OperationId(ApiDescription apiDescription)
-    {
-        IOperationIdHandler? handler = _operationIdHandlers.FirstOrDefault(h => h.CanHandle(apiDescription));
-        return handler?.Handle(apiDescription);
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/RemoveSecuritySchemesDocumentFilter.cs

@@ -1,25 +0,0 @@
-using Microsoft.OpenApi;
-using Swashbuckle.AspNetCore.SwaggerGen;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-/// <summary>
-/// This filter explicitly removes all security schemes from a named OpenAPI document.
-/// </summary>
-public class RemoveSecuritySchemesDocumentFilter : IDocumentFilter
-{
-    private readonly string _documentName;
-
-    public RemoveSecuritySchemesDocumentFilter(string documentName)
-        => _documentName = documentName;
-
-    public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
-    {
-        if (context.DocumentName != _documentName)
-        {
-            return;
-        }
-
-        swaggerDoc.Components?.SecuritySchemes?.Clear();
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/RequireNonNullablePropertiesSchemaTransformer.cs

@@ -0,0 +1,48 @@
+using System.Reflection;
+using System.Text.Json.Serialization.Metadata;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Ensures that all non-nullable properties are marked as required in the OpenAPI schema.
+/// </summary>
+/// <remarks>By default, only properties marked with the required keyword will actually show as required.
+/// Non-nullable reference types were not taken into account.</remarks>
+internal class RequireNonNullablePropertiesSchemaTransformer : IOpenApiSchemaTransformer
+{
+    /// <inheritdoc />
+    public Task TransformAsync(OpenApiSchema schema, OpenApiSchemaTransformerContext context, CancellationToken cancellationToken)
+    {
+        IEnumerable<string> additionalRequiredProps = schema.Properties?
+            .Where(p => schema.Required?.Contains(p.Key) != true) // If it's already required, skip
+            .Where(x => IsRequiredProperty(schema, context.JsonTypeInfo, x.Key))
+            .Select(x => x.Key)
+          ?? [];
+        schema.Required ??= new HashSet<string>();
+        foreach (var propKey in additionalRequiredProps)
+        {
+            schema.Required.Add(propKey);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private static bool IsRequiredProperty(OpenApiSchema schema, JsonTypeInfo jsonTypeInfo, string propertyName)
+    {
+        if (jsonTypeInfo.Properties.FirstOrDefault(p => p.Name == propertyName) is { } property)
+        {
+            return property.IsGetNullable is false;
+        }
+
+        // If we can't find the property in the type (e.g. discriminator '$type'), use the schema type information.
+        if (schema.Properties?.TryGetValue(propertyName, out IOpenApiSchema? schemaProperty) is true
+            && schemaProperty?.Type is { } propertyType)
+        {
+            return propertyType.HasFlag(JsonSchemaType.Null) is false;
+        }
+
+        return false;
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/SchemaIdHandler.cs

@@ -1,51 +0,0 @@
-using System.Text.RegularExpressions;
-using Umbraco.Extensions;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-// NOTE: Left unsealed on purpose, so it is extendable.
-public class SchemaIdHandler : ISchemaIdHandler
-{
-    public virtual bool CanHandle(Type type)
-        => type.Namespace?.StartsWith("Umbraco.Cms") is true;
-
-    public virtual string Handle(Type type)
-        => UmbracoSchemaId(type);
-
-    /// <summary>
-    ///     Generates a sanitized and consistent schema identifier for a given type following Umbraco's schema id naming conventions.
-    /// </summary>
-    protected string UmbracoSchemaId(Type type)
-    {
-        var name = SanitizedTypeName(type);
-
-        name = HandleGenerics(name, type);
-
-        if (name.EndsWith("Model") == false)
-        {
-            // because some models names clash with common classes in TypeScript (i.e. Document),
-            // we need to add a "Model" postfix to all models
-            name = $"{name}Model";
-        }
-
-        // make absolutely sure we don't pass any invalid named by removing all non-word chars
-        return Regex.Replace(name, @"[^\w]", string.Empty);
-    }
-
-    private string SanitizedTypeName(Type t) => t.Name
-        // first grab the "non-generic" part of any generic type name (i.e. "PagedViewModel`1" becomes "PagedViewModel")
-        .Split('`').First()
-        // then remove the "ViewModel" postfix from type names
-        .TrimEnd("ViewModel");
-
-    private string HandleGenerics(string name, Type type)
-    {
-        if (!type.IsGenericType)
-        {
-            return name;
-        }
-
-        // use attribute custom name or append the generic type names, ultimately turning i.e. "PagedViewModel<RelationItemViewModel>" into "PagedRelationItem"
-        return $"{name}{string.Join(string.Empty, type.GenericTypeArguments.Select(SanitizedTypeName))}";
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/SchemaIdSelector.cs

@@ -1,15 +0,0 @@
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class SchemaIdSelector : ISchemaIdSelector
-{
-    private readonly IEnumerable<ISchemaIdHandler> _schemaIdHandlers;
-
-    public SchemaIdSelector(IEnumerable<ISchemaIdHandler> schemaIdHandlers)
-        => _schemaIdHandlers = schemaIdHandlers;
-
-    public virtual string SchemaId(Type type)
-    {
-        ISchemaIdHandler? handler = _schemaIdHandlers.FirstOrDefault(h => h.CanHandle(type));
-        return handler?.Handle(type) ?? type.Name;
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/SortTagsAndPathsTransformer.cs

@@ -0,0 +1,42 @@
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Transforms the OpenAPI document to sort tags and paths alphabetically.
+/// </summary>
+internal class SortTagsAndPathsTransformer : IOpenApiDocumentTransformer
+{
+    /// <summary>
+    /// Transforms the specified OpenAPI document to sort its tags and paths alphabetically.
+    /// </summary>
+    /// <param name="document">The <see cref="OpenApiDocument"/> to modify.</param>
+    /// <param name="context">The <see cref="OpenApiDocumentTransformerContext"/> associated with the <paramref name="document"/>.</param>
+    /// <param name="cancellationToken">The cancellation token to use.</param>
+    /// <returns>The task object representing the asynchronous operation.</returns>
+    public Task TransformAsync(
+        OpenApiDocument document,
+        OpenApiDocumentTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        document.Tags = new SortedSet<OpenApiTag>(
+            document.Tags ?? Enumerable.Empty<OpenApiTag>(),
+            Comparer<OpenApiTag>.Create((a, b) => string.Compare(a.Name, b.Name, StringComparison.Ordinal)));
+
+        var sortedPaths = new OpenApiPaths();
+        foreach (KeyValuePair<string, IOpenApiPathItem> keyValuePair in document.Paths
+                     .OrderBy(x => x.Value.Operations?.Values
+                         .SelectMany(op => op.Tags ?? Enumerable.Empty<OpenApiTagReference>())
+                         .OrderBy(t => t.Name)
+                         .FirstOrDefault()?
+                         .Name)
+                     .ThenBy(x => x.Key))
+        {
+            sortedPaths.Add(keyValuePair.Key, keyValuePair.Value);
+        }
+
+        document.Paths = sortedPaths;
+        return Task.CompletedTask;
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/SubTypesHandler.cs

@@ -1,20 +0,0 @@
-using Umbraco.Cms.Api.Common.Serialization;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class SubTypesHandler : ISubTypesHandler
-{
-    private readonly IUmbracoJsonTypeInfoResolver _umbracoJsonTypeInfoResolver;
-
-    public SubTypesHandler(IUmbracoJsonTypeInfoResolver umbracoJsonTypeInfoResolver)
-        => _umbracoJsonTypeInfoResolver = umbracoJsonTypeInfoResolver;
-
-    protected virtual bool CanHandle(Type type)
-        => type.Namespace?.StartsWith("Umbraco.Cms") is true;
-
-    public virtual bool CanHandle(Type type, string documentName)
-        => CanHandle(type);
-
-    public virtual IEnumerable<Type> Handle(Type type)
-        => _umbracoJsonTypeInfoResolver.FindSubTypes(type);
-}

src/Umbraco.Cms.Api.Common/OpenApi/SubTypesSelector.cs

@@ -1,57 +0,0 @@
-using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.Options;
-using Umbraco.Cms.Api.Common.Serialization;
-using Umbraco.Cms.Core;
-using Umbraco.Cms.Core.Configuration.Models;
-using Umbraco.Cms.Core.Hosting;
-using Umbraco.Extensions;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class SubTypesSelector : ISubTypesSelector
-{
-    private readonly IHostingEnvironment _hostingEnvironment;
-    private readonly IHttpContextAccessor _httpContextAccessor;
-    private readonly IEnumerable<ISubTypesHandler> _subTypeHandlers;
-    private readonly IUmbracoJsonTypeInfoResolver _umbracoJsonTypeInfoResolver;
-
-    public SubTypesSelector(
-        IHostingEnvironment hostingEnvironment,
-        IHttpContextAccessor httpContextAccessor,
-        IEnumerable<ISubTypesHandler> subTypeHandlers,
-        IUmbracoJsonTypeInfoResolver umbracoJsonTypeInfoResolver)
-    {
-        _hostingEnvironment = hostingEnvironment;
-        _httpContextAccessor = httpContextAccessor;
-        _subTypeHandlers = subTypeHandlers;
-        _umbracoJsonTypeInfoResolver = umbracoJsonTypeInfoResolver;
-    }
-
-    public IEnumerable<Type> SubTypes(Type type)
-    {
-        var backOfficePath = _hostingEnvironment.GetBackOfficePath();
-        var swaggerPath = $"{backOfficePath}/swagger";
-
-        if (_httpContextAccessor.HttpContext?.Request.Path.StartsWithSegments(swaggerPath) ?? false)
-        {
-            // Split the path into segments
-            var segments = _httpContextAccessor.HttpContext.Request.Path.Value!
-                .Substring(swaggerPath.Length)
-                .TrimStart(Constants.CharArrays.ForwardSlash)
-                .Split(Constants.CharArrays.ForwardSlash);
-
-            // Extract the document name from the path
-            var documentName = segments[0];
-
-            // Find the first handler that can handle the type / document name combination
-            ISubTypesHandler? handler = _subTypeHandlers.FirstOrDefault(h => h.CanHandle(type, documentName));
-            if (handler != null)
-            {
-                return handler.Handle(type);
-            }
-        }
-
-        // Default implementation to maintain backwards compatibility
-        return _umbracoJsonTypeInfoResolver.FindSubTypes(type);
-    }
-}

src/Umbraco.Cms.Api.Common/OpenApi/SwaggerRouteTemplatePipelineFilter.cs

@@ -1,70 +0,0 @@
-using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Options;
-using Microsoft.OpenApi;
-using Swashbuckle.AspNetCore.SwaggerGen;
-using Swashbuckle.AspNetCore.SwaggerUI;
-using Umbraco.Cms.Core;
-using Umbraco.Cms.Core.Hosting;
-using Umbraco.Cms.Web.Common.ApplicationBuilder;
-using IHostingEnvironment = Umbraco.Cms.Core.Hosting.IHostingEnvironment;
-
-namespace Umbraco.Cms.Api.Common.OpenApi;
-
-public class SwaggerRouteTemplatePipelineFilter : UmbracoPipelineFilter
-{
-    public SwaggerRouteTemplatePipelineFilter(string name)
-        : base(name)
-        => PostPipeline = PostPipelineAction;
-
-    private void PostPipelineAction(IApplicationBuilder applicationBuilder)
-    {
-        if (SwaggerIsEnabled(applicationBuilder) is false)
-        {
-            return;
-        }
-
-        IOptions<SwaggerGenOptions> swaggerGenOptions = applicationBuilder.ApplicationServices.GetRequiredService<IOptions<SwaggerGenOptions>>();
-
-        applicationBuilder.UseSwagger(swaggerOptions =>
-        {
-            swaggerOptions.RouteTemplate = SwaggerRouteTemplate(applicationBuilder);
-        });
-
-        applicationBuilder.UseSwaggerUI(swaggerUiOptions => SwaggerUiConfiguration(swaggerUiOptions, swaggerGenOptions.Value, applicationBuilder));
-    }
-
-    protected virtual bool SwaggerIsEnabled(IApplicationBuilder applicationBuilder)
-        => applicationBuilder.ApplicationServices.GetRequiredService<IWebHostEnvironment>().IsProduction() is false;
-
-    protected virtual string SwaggerRouteTemplate(IApplicationBuilder applicationBuilder)
-        => $"{GetBackOfficePath(applicationBuilder).TrimStart(Constants.CharArrays.ForwardSlash)}/swagger/{{documentName}}/swagger.json";
-
-    protected virtual string SwaggerUiRoutePrefix(IApplicationBuilder applicationBuilder)
-        => $"{GetBackOfficePath(applicationBuilder).TrimStart(Constants.CharArrays.ForwardSlash)}/swagger";
-
-    protected virtual void SwaggerUiConfiguration(
-        SwaggerUIOptions swaggerUiOptions,
-        SwaggerGenOptions swaggerGenOptions,
-        IApplicationBuilder applicationBuilder)
-    {
-        swaggerUiOptions.RoutePrefix = SwaggerUiRoutePrefix(applicationBuilder);
-
-        foreach ((var name, OpenApiInfo? apiInfo) in swaggerGenOptions.SwaggerGeneratorOptions.SwaggerDocs.OrderBy(x => x.Value.Title))
-        {
-            swaggerUiOptions.SwaggerEndpoint($"{name}/swagger.json", $"{apiInfo.Title}");
-        }
-
-        // Add custom configuration from https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/
-        swaggerUiOptions.ConfigObject.PersistAuthorization = true; // persists authorization data so it would not be lost on browser close/refresh
-        swaggerUiOptions.ConfigObject.Filter = string.Empty; // Enable the filter with an empty string as default filter.
-
-        swaggerUiOptions.OAuthClientId(Constants.OAuthClientIds.Swagger);
-        swaggerUiOptions.OAuthUsePkce();
-    }
-
-    private string GetBackOfficePath(IApplicationBuilder applicationBuilder)
-        => applicationBuilder.ApplicationServices.GetRequiredService<IHostingEnvironment>().GetBackOfficePath();
-}

src/Umbraco.Cms.Api.Common/OpenApi/TagActionsByGroupNameTransformer.cs

@@ -0,0 +1,67 @@
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Transformer that tags operations based on their group name.
+/// </summary>
+internal class TagActionsByGroupNameTransformer : IOpenApiOperationTransformer, IOpenApiDocumentTransformer
+{
+    /// <summary>
+    /// Transforms the specified OpenAPI operation in order to tag it by its group name.
+    /// </summary>
+    /// <param name="operation">The <see cref="OpenApiOperation"/> to modify.</param>
+    /// <param name="context">The <see cref="OpenApiOperationTransformerContext"/> associated with the <paramref name="operation"/>.</param>
+    /// <param name="cancellationToken">The cancellation token to use.</param>
+    /// <returns>The task object representing the asynchronous operation.</returns>
+    public Task TransformAsync(
+        OpenApiOperation operation,
+        OpenApiOperationTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        if (context.Document is null || context.Description.GroupName is not { } groupName)
+        {
+            return Task.CompletedTask;
+        }
+
+        operation.Tags = new HashSet<OpenApiTagReference> { new(groupName) };
+        if (context.Document.Tags?.Any(t => t.Name == groupName) == true)
+        {
+            return Task.CompletedTask;
+        }
+
+        context.Document.Tags ??= new HashSet<OpenApiTag>();
+        context.Document.Tags.Add(new OpenApiTag { Name = groupName });
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    /// Transforms the specified OpenAPI document in order to clean up unused tags.
+    /// </summary>
+    /// <param name="document">The <see cref="OpenApiDocument"/> to modify.</param>
+    /// <param name="context">The <see cref="OpenApiDocumentTransformerContext"/> associated with the <paramref name="document"/>.</param>
+    /// <param name="cancellationToken">The cancellation token to use.</param>
+    /// <returns>The task object representing the asynchronous operation.</returns>
+    public Task TransformAsync(
+        OpenApiDocument document,
+        OpenApiDocumentTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        var usedTags = new HashSet<string?>(document.Paths
+            .SelectMany(p => (p.Value.Operations ?? []).Values)
+            .SelectMany(o => o.Tags ?? new HashSet<OpenApiTagReference>())
+            .Select(t => t.Name));
+
+        var tagsToRemove = (document.Tags ?? Enumerable.Empty<OpenApiTag>())
+            .Where(tag => usedTags.Contains(tag.Name) is false)
+            .ToList();
+
+        foreach (OpenApiTag tag in tagsToRemove)
+        {
+            document.Tags?.Remove(tag);
+        }
+
+        return Task.CompletedTask;
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/UmbracoBuilderOpenApiExtensions.cs

@@ -0,0 +1,81 @@
+using Umbraco.Cms.Core.DependencyInjection;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Extension methods for <see cref="IUmbracoBuilder"/> to register custom OpenAPI documents.
+/// </summary>
+public static class UmbracoBuilderOpenApiExtensions
+{
+    /// <summary>
+    /// Registers a custom OpenAPI document with Umbraco's defaults applied.
+    /// </summary>
+    /// <param name="builder">The Umbraco builder.</param>
+    /// <param name="documentName">The document name. Matches the <c>[MapToApi]</c> value on controllers to include.</param>
+    /// <param name="configure">Optional callback to customize the document.</param>
+    /// <returns>The same <see cref="IUmbracoBuilder"/> for chaining.</returns>
+    /// <remarks>
+    /// <para>
+    /// The following defaults are applied to the document and can be customized or overridden via the
+    /// <paramref name="configure"/> callback:
+    /// </para>
+    /// <list type="bullet">
+    ///   <item>
+    ///     <description>
+    ///     Endpoints are filtered by <c>[MapToApi(documentName)]</c>; only matching endpoints appear in the document.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     Schema reference IDs are generated by <see cref="UmbracoSchemaIdGenerator.CreateSchemaReferenceId"/>, applying
+    ///     Umbraco naming conventions to types under the <c>Umbraco.Cms</c> namespace and falling back to the framework
+    ///     default for everything else. Register your own <c>CreateSchemaReferenceId</c> delegate via
+    ///     <see cref="BackOfficeOpenApiDocumentBuilder.ConfigureOpenApiOptions"/> to override.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     Operation IDs are generated by <see cref="UmbracoOperationIdTransformer"/>. Register your own
+    ///     <see cref="Microsoft.AspNetCore.OpenApi.IOpenApiOperationTransformer"/> via
+    ///     <see cref="BackOfficeOpenApiDocumentBuilder.ConfigureOpenApiOptions"/> to override.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     Operations are tagged by their controller's API group name, and the resulting tags and paths are sorted
+    ///     for stable, diffable document output.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     Redundant JSON-equivalent media types (such as <c>text/json</c>, <c>application/*+json</c>, and
+    ///     <c>text/plain</c>) are stripped from request and response content when <c>application/json</c> is present,
+    ///     so the document doesn't list spurious media types that ASP.NET Core adds by default.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     Non-nullable properties are marked as <c>required</c> in the schema so generated client SDKs reflect
+    ///     C# nullability. Override via <see cref="BackOfficeOpenApiDocumentBuilder.ConfigureOpenApiOptions"/>
+    ///     if your types don't follow this convention.
+    ///     </description>
+    ///   </item>
+    ///   <item>
+    ///     <description>
+    ///     The document is registered in the OpenAPI UI document selector dropdown. Call
+    ///     <see cref="BackOfficeOpenApiDocumentBuilder.ExcludeFromUi"/> to opt out.
+    ///     </description>
+    ///   </item>
+    /// </list>
+    /// </remarks>
+    public static IUmbracoBuilder AddBackOfficeOpenApiDocument(
+        this IUmbracoBuilder builder,
+        string documentName,
+        Action<BackOfficeOpenApiDocumentBuilder>? configure = null)
+    {
+        var documentBuilder = new BackOfficeOpenApiDocumentBuilder(documentName);
+        configure?.Invoke(documentBuilder);
+        documentBuilder.Build(builder);
+        return builder;
+    }
+}

src/Umbraco.Cms.Api.Common/OpenApi/UmbracoOpenApiOptions.cs

@@ -0,0 +1,48 @@
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Options for configuring OpenAPI documents and UI.
+/// </summary>
+/// <remarks>
+/// These options are populated by <c>AddUmbracoOpenApi</c> during DI configuration, which resolves the back-office path
+/// from <see cref="Core.Hosting.IHostingEnvironment"/> and sets the default values for
+/// <see cref="RouteTemplate"/> and <see cref="UiRoutePrefix"/>. Consumers that read this options type before
+/// <c>AddUmbracoOpenApi</c> has run will observe the uninitialised defaults (empty strings for the route properties). 
+/// </remarks>
+public class UmbracoOpenApiOptions
+{
+    /// <summary>
+    /// Gets or sets whether OpenAPI documents are enabled.
+    /// Configured to <c>true</c> in non-production environments by default; <c>false</c> until configured.
+    /// This avoids exposing API structure on public-facing websites.
+    /// </summary>
+    public bool Enabled { get; set; }
+
+    /// <summary>
+    /// Gets or sets whether the default OpenAPI UI is enabled.
+    /// Only applies when <see cref="Enabled"/> is true.
+    /// Set to false to disable the default UI while keeping OpenAPI documents available,
+    /// allowing you to use an alternative UI.
+    /// Default: true.
+    /// </summary>
+    public bool DefaultUiEnabled { get; set; } = true;
+
+    /// <summary>
+    /// Gets or sets the route template for OpenAPI JSON documents.
+    /// Use <c>{documentName}</c> as a placeholder for the document name.
+    /// </summary>
+    /// <remarks>
+    /// Populated by <c>AddUmbracoOpenApi</c> to <c>"{backOfficePath}/openapi/{documentName}.json"</c>. The initial
+    /// <see cref="string.Empty"/> default is a sentinel for "not yet configured" — it is not a usable route template.
+    /// </remarks>
+    public string RouteTemplate { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the route prefix for OpenAPI UI.
+    /// </summary>
+    /// <remarks>
+    /// Populated by <c>AddUmbracoOpenApi</c> to <c>"{backOfficePath}/openapi"</c>. The initial <see cref="string.Empty"/>
+    /// default is a sentinel for "not yet configured" — it is not a usable route prefix.
+    /// </remarks>
+    public string UiRoutePrefix { get; set; } = string.Empty;
+}

src/Umbraco.Cms.Api.Common/OpenApi/UmbracoOperationIdTransformer.cs

@@ -0,0 +1,102 @@
+using Asp.Versioning;
+using Microsoft.AspNetCore.Mvc.ApiExplorer;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Microsoft.OpenApi;
+using Umbraco.Extensions;
+
+namespace Umbraco.Cms.Api.Common.OpenApi;
+
+/// <summary>
+/// Transforms OpenAPI operation IDs using Umbraco's naming conventions.
+/// </summary>
+/// <remarks>
+/// This transformer can be registered manually for custom OpenAPI configurations.
+/// </remarks>
+public class UmbracoOperationIdTransformer : IOpenApiOperationTransformer
+{
+    /// <summary>
+    /// Transforms the specified OpenAPI operation, setting its operation ID using a custom selector.
+    /// </summary>
+    /// <param name="operation">The <see cref="OpenApiOperation"/> to modify.</param>
+    /// <param name="context">The <see cref="OpenApiOperationTransformerContext"/> associated with the <paramref name="operation"/>.</param>
+    /// <param name="cancellationToken">The cancellation token to use.</param>
+    /// <returns>The task object representing the asynchronous operation.</returns>
+    public Task TransformAsync(
+        OpenApiOperation operation,
+        OpenApiOperationTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        var operationId = GenerateOperationId(context);
+        if (operationId is not null)
+        {
+            operation.OperationId = operationId;
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private static string? GenerateOperationId(OpenApiOperationTransformerContext context)
+    {
+        ApiDescription apiDescription = context.Description;
+        if (apiDescription.ActionDescriptor is not ControllerActionDescriptor controllerActionDescriptor)
+        {
+            // Minimal APIs and other non-MVC endpoints don't carry a ControllerActionDescriptor; leave their
+            // operation ID untouched so the framework's default applies.
+            return null;
+        }
+
+        ApiVersion defaultVersion = context.ApplicationServices.GetRequiredService<IOptions<ApiVersioningOptions>>().Value.DefaultApiVersion;
+        var httpMethod = apiDescription.HttpMethod?.ToLower().ToFirstUpper() ?? "Get";
+
+        // if the route info "Name" is supplied we'll use this explicitly as the operation ID
+        // - usage example: [HttpGet("my-api/route}", Name = "MyCustomRoute")]
+        if (string.IsNullOrWhiteSpace(apiDescription.ActionDescriptor.AttributeRouteInfo?.Name) == false)
+        {
+            var explicitOperationId = apiDescription.ActionDescriptor.AttributeRouteInfo!.Name;
+            return explicitOperationId.InvariantStartsWith(httpMethod)
+                ? explicitOperationId
+                : $"{httpMethod}{explicitOperationId}";
+        }
+
+        var relativePath = apiDescription.RelativePath;
+
+        if (string.IsNullOrWhiteSpace(relativePath))
+        {
+            throw new InvalidOperationException(
+                $"There is no relative path for controller action {apiDescription.ActionDescriptor.RouteValues["controller"]}");
+        }
+
+        // Remove the prefixed base path with version, e.g. /umbraco/management/api/v1/tracked-reference/{id} => tracked-reference/{id}
+        var unprefixedRelativePath = OperationIdRegexes
+            .VersionPrefixRegex()
+            .Replace(relativePath, string.Empty);
+
+        // Remove template placeholders, e.g. tracked-reference/{id} => tracked-reference/Id
+        var formattedOperationId = OperationIdRegexes
+            .TemplatePlaceholdersRegex()
+            .Replace(unprefixedRelativePath, m => $"By{m.Groups[1].Value.ToFirstUpper()}");
+
+        // Remove dashes (-) and slashes (/) and convert the following letter to uppercase with
+        // the word "By" in front, e.g. tracked-reference/Id => TrackedReferenceById
+        formattedOperationId = OperationIdRegexes
+            .ToCamelCaseRegex()
+            .Replace(formattedOperationId, m => m.Groups[1].Value.ToUpper());
+
+        // Get map to version attribute
+        string? version = null;
+
+        var versionAttributeValue = controllerActionDescriptor.MethodInfo.GetMapToApiVersionAttributeValue();
+
+        // We only want to add a version, if it is not the default one.
+        if (string.Equals(versionAttributeValue, defaultVersion.ToString()) == false)
+        {
+            version = versionAttributeValue;
+        }
+
+        // Return the operation ID with the formatted http method verb in front, e.g. GetTrackedReferenceById
+        return $"{httpMethod}{formattedOperationId.ToFirstUpper()}{version}";
+    }
+}