Anthropic API field note
Anthropic 529 overloaded_error: retry without causing a storm
Handle Anthropic API 529 overload responses with safe retry boundaries, jitter, idempotency awareness, and request-ID preservation.
Anthropic uses 529 for temporary API overload. The response is different from a schema or authentication error: preserve request-id, reduce concurrency, and retry within a bounded policy. Streaming requests also need handling for errors that arrive after an initial successful HTTP response.
Treat the complete response as an evidence record: status, headers, provider code, request identifier, method, and raw body. The sequence below separates what the response proves from the checks still needed before a safe retry or code change.
Diagnostic procedure
Work from evidence to recovery.
- 01
Keep the request identifier
Log the request-id response header with model, region, latency, and attempt number.
- 02
Reduce synchronized pressure
Use full or decorrelated jitter so concurrent workers do not retry at the same instant.
- 03
Set a recovery boundary
Cap attempts and cumulative delay, then fail over or surface a temporary-unavailable state.
529 overloaded_error → 50 workers retry after exactly 1 second
Bounded exponential backoff + jitter + concurrency reduction + request-id log
Evidence
HTTP 429: A rate, quota, concurrency, or resource lock limit blocked the request.
Retry-After is present; it should take precedence over a guessed delay.
The reported request window has no remaining capacity.
Next checks
01Parse Retry-After as either delta-seconds or an HTTP date before scheduling the next attempt.
No account · no upload · no endpoint calledOpen the full incident decoder and operating notes →
FAQ
Before you ship
Does APITC send this evidence to an API?
No. The matching and calculations in the linked workbench run in the active browser tab.
Should every Anthropic 529 response be retried?
No. Retry behavior depends on the method, idempotency protection, provider instructions, and whether the failure is temporary.
Protocol behavior checked against the Anthropic API errors. Recheck your pinned provider/API version before production deployment.