runtime-validation

Catch the bugs a green test suite misses by observing REAL runtime behavior — tail application logs during test/server runs, validate API responses against their schema contracts, and assert data-integrity invariants (density ≤ 1.0, %≤100, referential integrity). Use when unit tests pass 100% but the running app still errors, when a Pydantic/Zod/serde validation error or schema drift shows up only at runtime, when reviewing whether a test suite actually exercises the running system, or when someone says "all tests pass but it's broken", "smoke test", "the mocks lied", or "verify it works live".