- All source code, comments, variable names, function names, test descriptions, and commit messages must be written in English only.
- Responses to the user may be in any language.
- All feature work and bug fixes must follow TDD (Test-Driven Development).
- Write the failing test first. Watch it fail. Then write the minimal code to make it pass.
- Never write production code without a failing test that demands it.
- If code was written before its test, delete it and start over from the test.
- When generating implementation plans, every task must include explicit RED → GREEN → REFACTOR steps.