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

# Errors

> Public API error format and common error codes.

Errors use a consistent envelope.

```json theme={null}
{
  "error": {
    "code": "validation_failed",
    "message": "Input is invalid.",
    "details": [
      {
        "field": "input.vendor",
        "code": "required",
        "message": "Vendor is required."
      }
    ],
    "requestId": "req_123"
  }
}
```

`requestId` is included when the request sends `X-Request-Id`.

## Common errors

| HTTP status | Code                    | Meaning                                                                |
| ----------- | ----------------------- | ---------------------------------------------------------------------- |
| `400`       | `validation_failed`     | Request body is invalid.                                               |
| `400`       | `lane_required`         | The agent has multiple lanes and the request did not include `laneId`. |
| `400`       | `lane_not_supported`    | The requested `laneId` is not public for this agent.                   |
| `400`       | `message_required`      | A chat lane run is missing `input.message`.                            |
| `400`       | `message_too_long`      | A chat lane run has `input.message` longer than 20,000 characters.     |
| `401`       | `missing_api_key`       | Missing bearer token.                                                  |
| `401`       | `invalid_api_key`       | The bearer token is not a valid Erstan API key.                        |
| `401`       | `api_key_revoked`       | The key was revoked.                                                   |
| `401`       | `api_key_expired`       | The key has expired.                                                   |
| `401`       | `api_key_user_inactive` | The user who created the key no longer belongs to the workspace.       |
| `403`       | `scope_denied`          | The key does not have the required scope.                              |
| `403`       | `agent_not_published`   | The agent is not published.                                            |
| `403`       | `agent_disabled`        | The agent is disabled.                                                 |
| `404`       | `agent_not_found`       | The agent is not visible to the key.                                   |
| `404`       | `run_not_found`         | The run was not started by this key or does not exist.                 |
| `500`       | `internal_error`        | Unexpected server error.                                               |