Owns a cheapest-first three-tier verification ladder — Tier 1 syntactic (grep / ast-grep / read), Tier 2 semantic-no-execution (typecheck / build / lint), Tier 3 execution (run the covering test, or a minimal synthesized repro) — and reports the result as an evidence receipt (confirms / contradicts / ambiguous / null). It never scores; `confidence(code)` owns the number. Two consumer shapes: claim-verification (read-only, feeds `confidence(code)`) and change-verification (post-apply green/red gate). Called by `verification-receipt.md` (pr-reviewer Tier 2/3), `bug-fix-verifier`, `feature-pr-verifier`, and the `aw-executor` Phase 4 checks loop. Use when a finding or a change needs executed proof, not just a plausible-sounding claim. Triggers on "verify this claim", "does this actually happen at runtime", "prove this behavior", "run this to confirm", "/verify-behavior".