Runtime testing (PR #2986 validation, finding GS-002) showed the
approve-after-revoke refusal — the PR's own deliberate behavior delta —
surfacing as "ERROR Approval handler threw" with a stack trace, and the
requester being told the apply "failed". Enforcement was correct; the
telemetry dressed an expected guard refusal as a runtime failure.
The a2a route's deny now throws a typed GuardDenyError (guard leaf), and
applyA2aMessageGate catches exactly that: the requester is notified
"Message approved, but not delivered — no longer authorized: <reason>"
and the host logs a warning. Anything else still propagates to the
response handler's crash path. Covers all three replay refusals the same
way: destination revoked while pending, mismatched grant, already-consumed
grant.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Moshe Krupper
82d9171985