Code
Map tests to requirements
Which requirement each test covers, and which have no test at all.
Fill it in
A PRD or requirements document.
Where the tests are.
Requirements with no test, and tests with no requirement.
Your prompt
Build a traceability matrix. Tests: [the test suite] Map requirement to test, both directions. The forward direction finds what is untested; the reverse finds tests that assert something nobody asked for, which is usually a requirement that changed and a test that did not. Call out the gaps explicitly, and rank them by what the requirement is worth. Untested error handling on payment is not the same as untested tooltip copy, and a matrix that presents them equally gets ignored. Do not count partial coverage: a test that touches a requirement is not the same as one that verifies it, and marking those as covered is how a matrix ends up reassuring everyone about nothing.
Use Map tests to requirementsOpens with everything above already filled in.
Why this works
Mapped only forwards, a matrix finds untested requirements. Mapped both ways it also finds tests asserting something nobody asked for, which is usually a requirement that changed and a test that did not.