CLAUDE.md: OpenAPI.json maintenance

CLAUDE.md

@@ -419,6 +419,16 @@ APIs use `Asp.Versioning.Mvc`:
 - Delivery API: `/umbraco/delivery/api/v{version}/*`
 - OpenAPI/Swagger docs per version
 
+### 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".
@@ -461,6 +471,7 @@ The `Tests:Database:DatabaseType` setting controls which database is used:
 - `"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 |

src/Umbraco.Web.UI.Client/docs/clean-code.md

@@ -462,6 +462,23 @@ export class UmbDocumentActionButton extends LitElement {
 - Remove unused imports, functions, variables
 - Clean up console.logs before committing
 
+### Feature Parity with Core Equivalents
+
+When implementing a new component that mirrors an existing core or sibling implementation (e.g. a new collection action alongside document/media/member equivalents), do a side-by-side comparison against the core version before considering it done.
+
+**Checklist**:
+
+1. **Full API surface**: Read the reference implementation's controller/API usage line by line. Every method call, callback, and property access on controllers in the reference must have a counterpart in the new implementation — don't cherry-pick only the obvious ones.
+2. **Error handling**: Match the core's error handling pattern (e.g. `.catch(() => {})` on `execute()` calls) to prevent unhandled promise rejections.
+3. **Type hierarchy**: Before defining new interfaces, search for existing base types (e.g. `UmbNamedEntityModel` vs `UmbEntityModel`) that already declare the fields you need. Use the most specific base.
+4. **UI consistency**: Check CSS from sibling implementations (e.g. `max-height` on scroll containers, icon fallbacks like `?? 'icon-document'`).
+5. **Context-appropriate strings**: Don't reuse localization keys from another domain (e.g. `create_noDocumentTypes` in an elements context). Either create a new key or use only the inline fallback text.
+
+**Core components to compare against** (common patterns):
+- Collection create actions: `src/packages/core/collection/action/create/collection-create-action.element.ts`
+- Entity create option modals: `src/packages/core/entity-action/common/create/modal/entity-create-option-action-list-modal.element.ts`
+- Document/media/member equivalents in their respective `src/packages/` directories
+
 ### Patterns to Avoid
 
 **Don't**:

src/Umbraco.Web.UI.Client/docs/style-guide.md

@@ -196,6 +196,16 @@ export class UmbBadElement extends LitElement {
 - `@cssprop` - CSS custom properties
 - `@csspart` - CSS parts
 
+### Third-Party Library Names
+
+Use the correct capitalization for third-party libraries:
+
+| Library | Correct | Incorrect              |
+|---------|---------|------------------------|
+| Tiptap  | Tiptap  | TipTap, tipTap, TIPTAP |
+| Lit     | Lit     | LIT, lit (in prose)    |
+| RxJS    | RxJS    | rxjs (in prose), RXJS  |
+
 ### Documentation
 
 - **Public APIs**: JSDoc comments with `@description`, `@param`, `@returns`, `@example`