These are the user's opinions, not universal rules. Where a repo has an established convention that conflicts, the repo wins — match the surrounding code and say what you noticed.
Read only the file that matches what you're doing.
- TESTING.md — what to assert, what to mock, TDD flow. Read when writing or reviewing tests, or deciding test coverage.
- SECURITY.md — input validation at boundaries, path confinement, logging. Read when handling external input, file paths, or adding log statements.
- DOTNET.md — C#/.NET conventions. Read when writing or reviewing C#.