Review findings on the salvaged #60332 breaker, fixed as follow-ups:
- restore_primary_runtime() now resets the streak (third provider-swap
path; without it a recovered primary was short-circuited before a
single attempt and could never be re-proven healthy except via /model).
- interruptible_api_call (non-streaming) now carries the same breaker
(guard at entry, bump on stale_call_kill, reset on success). Quiet-mode
/ subagent / headless sessions — the profile most like #58962's
unattended 494-failure session — take this path and had the identical
infinite stale-retry class.
- Partial-stream stub return now resets the streak (chunks were received,
provider demonstrably responsive).
- Consolidated the triple-duplicated counter arithmetic into shared
helpers (_stale_streak/_bump_stale_streak/_reset_stale_streak/
_check_stale_giveup) with one canonical comment block; error message
now says 'consecutive stale attempts' (the counter counts kills, not
turns — a single turn can produce several).
4 new tests (restore resets / no-op restore keeps latch / non-streaming
short-circuit / non-streaming success reset).
d43863f005