Per-plan API rate and concurrency limits are now published

The API limits reference now spells out the per-plan rate limits (sustained requests per second, plus a burst allowance on Agents) and concurrency limits (simultaneous in-flight requests) for both the audio (TTS) and Agents surfaces. Limits apply per account, not per API key.

429 Too Many Requests responses are now self-describing: a Retry-After header, an error.code that distinguishes rate_limited from concurrency_limited, and an error.docs_url that links straight to the limits reference and how to raise them.

See the Build changelog for the summary.