A2A authenticates every inbound request via bearer token in do_POST
(401 before dispatch). Without overriding authorization_is_upstream=True,
the gateway's per-platform user allow-list ({PLATFORM}_ALLOWED_USERS)
rejects A2A peers because their identity is a token-derived name or
pod IP, not a platform account in any configured allow-list. Messages
never reach the agent and callers get empty replies.
This is authorization delegated to the bearer-token transport, not a
fail-open: every request is 401'd if the credential is wrong.
Reported by kuangmi-bit (PR #41711 comment, Jun 27).
Attribution: gfdsa's a2a-hermes repro fixture (LOCAL PATCH triad-hermoperator).
The other two patches from gfdsa's fixture were already in our branch:
- k8s Agent Card URL derivation (_request_public_url, commit ea59b85c2)
- send() gating on metadata['notify'] (reply-capture fix, commit ea59b85c2)
All 168 tests pass (151 unit + 17 integration).
Ben Kamholtz
3271cb6907