Failure Index / Rate limits & availability · warning · LangChain · OpenAI Agents SDK · CrewAI

Agent tool call times out (TimeoutError / ReadTimeout)

The upstream service didn't answer inside the timeout window. Agents amplify this failure: one slow dependency stalls the whole chain, and naive retries triple the wall-clock time.

The error

TimeoutError langchain tool
agent tool read timeout
httpx.ReadTimeout agent

Root cause

The service is degraded or the request is genuinely heavy (large query, big document). Default client timeouts (often 5-30s) may also simply be too tight for the operation.

The fix

Check the service's health first. If the operation is legitimately slow, raise the timeout for that specific tool and consider breaking large requests into smaller ones. Add one retry with backoff for transient slowness.

Preventing it next time

Set per-tool timeouts based on each tool's real latency profile (p99), not one global default — and record latency per step so you see degradation before it becomes timeouts.

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Related failures

Agent hits HTTP 429: rate limit exceeded (often from its own retry loop)agent 429 too many requests loopGmail API rate limit: ~25 requests/minute per usergmail api rate limit exceeded agent