Use when creating or editing a CLAUDE.md file, or when a change alters conventions that CLAUDE.md documents. Covers what belongs in CLAUDE.md versus CONTRIBUTING.md, the expected structure, and the size limit.
Use when reviewing code — a diff, a pull request, or a peer agent's output. Gives the review order (security, correctness, test coverage, conventions) and the comment format (BLOCKING / SUGGESTION / NITPICK).
Use when asked to simplify, refactor, or reduce complexity in existing code, or when a change has left code harder to follow. Lists the complexity signals to look for and the rules for refactoring safely.
Use when implementing a new feature or a bugfix, before writing implementation code. Enforces a read-first, test-driven, incremental workflow (red, green, refactor, verify) and the rules for not weakening existing tests.
Use before making structural changes to code — renaming a symbol, deleting code, adding an import, or altering a shared DTO or interface. Covers how to establish blast radius before the edit rather than after.
Use when writing or modifying code under web-ui/ — React 19, TypeScript, Tailwind, TanStack Query. Covers this project's state, typing, import, component, WebSocket, and graph-rendering conventions plus the checks that must pass before declaring done.