Follow-up to the salvaged #51657: the conversation loop returns the
retry-exhaustion sentinel as BOTH final_response and error, so the
original detector (which required final_response to be falsy) never
fired on real exhaustion turns — the sentinel text was delivered
verbatim into the channel, exactly the #51628 poisoning vector. Detect
the sentinel echo, blank it before empty-response normalization, and
never suppress a turn whose final_response is genuine model text.
Also: dedupe-guard mock fix in the test fixture (has_platform_message_id
must return False, not a truthy MagicMock) and two guard tests
(real answer never suppressed; interrupted/failed never classified).
Teknium
09b6d22dfe