retryableHttp() now retries only 408 (Request Timeout), 429 (Too Many
Requests), and 503 (Service Unavailable). 500-and-other-5xx fail
immediately so the circuit-breaker registers them as a single
failure rather than smearing across retry attempts. Retry-After
honoured (numeric + HTTP-date), capped reasonably.
Attempt budget bumped to 6 so a burst of 5 transient 503s can recover
within ONE circuit-permitted call — the original concern from #311.
Note: CircuitBreaker is already applied OUTSIDE the logical Brain
operation by the MCP tool layer, not around each HTTP retry. The
nesting report was stale at this code shape; the real drift was the
retryableHttp() retry set + budget.
Pest coverage in CircuitBreakerTest:
- Recovered 503 burst → circuit stays closed, no failure registered
- Exhausted 503 burst → ONE breaker failure (not five)
- 429 + Retry-After 1 → sleeps 1s, no breaker failure
- 500 → immediate breaker failure, no retry
Co-authored-by: Codex <noreply@openai.com>
Closes tasks.lthn.sh/view.php?id=311
a1a0981b06