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

# Idempotency

> Retry chat requests safely with requestId.

`POST /agents/{agentId}/chat` accepts an optional UUID `requestId`.

```json theme={null}
{
  "message": "How do I reset my password?",
  "requestId": "9d2c8360-7321-42ae-a64c-c11053336f73"
}
```

Reuse the same `requestId` only for an exact retry of the same chat input. Reusing it with different input returns `409 request_id_conflict`.

<Tip>
  Generate the UUID before the first request and persist it until the request succeeds or fails permanently.
</Tip>