Anthropic 429 with no retry-after header: that is the monthly spend cap, and retries will never work

TL;DR

The response has no retry-after header, and waiting plus retrying changes nothing. Note a related but different case: a 400 with the message starting "You have reached your specified API usage limits" is a spend limit you set yourself on the billing page, not the tier cap.

Steps

1. Every request returns HTTP 429, rate_limit_error. The response has no retry-after header, and waiting plus retrying changes nothing.
2. Look at error.details.error_code on the Messages API response. If it is enforced_spend_limit_reached, your organization hit its tier's monthly spend cap, not a rate limit. Spend-cap pauses last until 00:00 UTC on the first day of the next month. Note a related but different case: a 400 with the message starting "You have reached your specified API usage limits" is a spend limit you set yourself on the billing page, not the tier cap.
3. Confirm on the Billing page in the Claude Console what the cap and current spend are.
4. To restore access now, request a higher limit (Rate limits page) or contact support for urgent needs.
5. If the 400 variant, raise or remove the self-set limit on the billing page.
6. Do not burn retry budget on this: the SDK's automatic retries fail until access resumes.

When to use

You are seeing this: Every request returns HTTP 429, rate\limit\error. Use this skill when you run into "Anthropic 429 with no retry-after header: that is the monthly spend cap, and retries will never work".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

Look at error.details.error\_code on the Messages API response.

Edge cases

• Note a related but different case: a 400 with the message starting "You have reached your specified API usage limits" is a spend limit you set yourself on the billing page, not the tier cap.

The rate limits doc distinguishes the tier spend-cap 429 (no retry-after, errorcode enforcedspendlimitreached) from ordinary rate limits, and documents the self-set spend limit 400. Verified live at https://docs.anthropic.com/en/api/rate-limits and https://docs.anthropic.com/en/api/errors.