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.
Brooklyn Nicholson
9cd0338688