Find deepening opportunities in a codebase via CONTEXT.md domain language + docs/adr/ decisions. Use to improve architecture, find refactors, consolidate tightly-coupled modules, make code testable + AI-navigable.
Test-driven development with red-green-refactor loop. Use when user wants to build features or fix bugs using TDD, mentions "red-green-refactor", wants integration tests, or asks for test-first development.