> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cortex.foundation/llms.txt
> Use this file to discover all available pages before exploring further.

# concurrency_limit_reached

> Too many runs at once. HTTP 429.

|           |                                                                     |
| --------- | ------------------------------------------------------------------- |
| HTTP      | `429`                                                               |
| `code`    | `concurrency_limit_reached`                                         |
| `type`    | `https://docs.cortex.foundation/problems/concurrency_limit_reached` |
| Retryable | no                                                                  |

Too many concurrent agent runs for this plan.

```json theme={null}
{
  "type": "https://docs.cortex.foundation/problems/concurrency_limit_reached",
  "title": "Too many runs at once",
  "status": 429,
  "code": "concurrency_limit_reached",
  "request_id": "req_…"
}
```

## Related

* [Errors](/reference/errors) - how to branch on `code`, and what not to render from `detail`.
* [Problem catalog](/problems) - every code, its status, and whether retrying helps.
* [Troubleshooting](/getting-started/troubleshooting) - what a message in the product means.