Review follow-up (egilewski): the previous commit only hedged the guidance
text; the exact Anthropic 400 was still classified, persisted, and surfaced
as confirmed billing exhaustion. Carry the ambiguity all the way through:
- agent/error_classifier.py: 'out of extra usage' matches on the 400 and
status-less paths now attach error_context {billing_unverified,
possible_content_filter}. Reason stays FailoverReason.billing (rotation +
fallback remain the right recovery either way); ClassifiedError grows a
billing_unverified property.
- agent/credential_pool.py: new FAILURE_REASON_BILLING_UNVERIFIED. An
unverified billing exhaustion gets the short transient cooldown instead of
the one-hour bench, regardless of pool size: a content-filter rejection
leaves the credential healthy and fails identically on every key, and the
hour-long sole-credential latch is what replayed the stored error and made
real fixes look ineffective. A true 402 keeps the full bench. The marker
persists with the entry so a restart cannot upgrade it back to a bench.
- agent/agent_runtime_helpers.py + run_agent.py: recover_with_credential_pool
threads billing_unverified and hands the pool 'billing_unverified' as the
persisted failure_reason.
- agent/conversation_loop.py: the fallback-switch status, max-retries status,
terminal label, and both structured terminal results hedge when the verdict
is unverified. New _billing_terminal_label + _billing_failure_result build
the returned terminal response in one place; the result dict now carries
billing_unverified and the billing_block gains 'unverified': true. The
confirmed-billing path (a real 402 or an API-key credit depletion) keeps
the original assertive wording, so the caveat no longer dilutes it.
Regression tests: classifier marking (400 + status-less + unambiguous-body
negative), pool cooldown TTLs + persistence round-trip, pool failure_reason
plumbing, and the returned terminal response for both unverified and
confirmed verdicts.
Note: tests/agent/test_credential_pool_routing.py::TestFailureAttribution::
test_unmatched_key_does_not_retry_only_pool_entry fails identically on
current main without this change (pre-existing, unrelated).
The sole-credential cooldown sized the bench from the raw HTTP status, but
403 is overloaded: error_classifier maps OpenRouter's "key limit exceeded"
and xAI's spending-limit block to FailoverReason.billing, while an edge
throttle with the same status is transient. Only 402 was excluded from the
short cooldown, so a spent account on a single key retried every 60 seconds
and re-failed forever.
Thread the classified reason from recover_with_credential_pool through
mark_exhausted_and_rotate to _exhausted_ttl. Billing keeps the full bench
regardless of status; everything else transient still recovers in 60s. The
verdict is stored on the entry (_EXTRA_KEYS, so it persists to auth.json) —
without that a restart would re-read a bare 403 and downgrade the bench.
Tests: sole billing-403 stays benched, survives reload, unclassified 403
still recovers; call-site coverage that the reason actually reaches the pool.
Three existing kwargs assertions updated for the new argument.
next_available_at() was computing the full 1-hour TTL for a sole
credential on a 429, contradicting the 60s cooldown in _available_entries.
The fallback restore gate (agent_runtime_helpers) uses next_available_at
to decide when to switch back from fallback to primary — so the agent
stayed on fallback for an hour instead of ~60s.
Add sole_credential computation in next_available_at mirroring
_available_entries, and a test verifying the short cooldown propagates.
A pool with only one usable (non-DEAD) credential has nothing to rotate to.
On a transient throttle (429 rate-limit, 403 edge-throttle, 5xx) the offending
key was benched for a full hour (EXHAUSTED_TTL_429/DEFAULT), so single-key /
no-fallback setups got an hour of hard failures for a throttle that resets in
seconds. The pool already special-cases 401 to recover quickly for single-key
setups; extend that to transient throttles when the credential is the sole
non-DEAD entry. 402 (billing/quota) keeps the full bench — a quick retry can't
help. Provider-supplied reset_at still overrides.
Adds tests covering sole 429/403 recovery, 402 full-bench, and multi-key
(no early recovery).
Jack Lau