Test-driven regression guard for AI coding agents. After every code change, TDAD looks up impacted tests via a code-test dependency graph and runs only the affected tests before submitting a patch. It also enforces that every change includes a new regression test. Supports Python, JavaScript/TypeScript, Go, Java, Rust, and Dart projects. Evaluated on SWE-bench Verified, it reduced AI-introduced regressions by 72%.