Every `MUTATION` row of `docs/guard-inventory.md` now carries a DECLARED clause mutation that is applied to an isolated copy of the repository on every suite run, with the row's own named test required to go red carrying a declared diagnostic. Manifest and MUTATION rows are compared for set equality both directions; the other 22 guards each carry a stated reason, compared the same way.
Measured rather than assumed: 12 of 13 guards admit a single-clause mutation; `instrumentation_faults` does not, and that entry carries the surviving finer mutation, re-run every suite.
Nine cold cross-family review rounds. Rounds 1, 2, 7 and 8 each found real mechanism defects — two mutations that measured nothing, an incomplete git-environment sanitisation, a reset that restored its own mutant, and a proof of that fix which was not itself isolated. All fixed and witnessed red.
fixes#790
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Co-authored-by: Timothy <timothy@noreply.gitea.tblindustries.be>
