> ## Documentation Index
> Fetch the complete documentation index at: https://notte-experiment-visibility-md-links.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# API Error Codes

> API error responses and status codes

The API uses standard HTTP status codes and returns structured error responses.

## HTTP status codes

| Status | Description                                                |
| ------ | ---------------------------------------------------------- |
| `200`  | Success                                                    |
| `401`  | Authentication failed — invalid or missing API key         |
| `422`  | Validation error — malformed request or invalid parameters |
| `429`  | Rate limit exceeded                                        |
| `500`  | Internal server error                                      |
| `529`  | Cluster overloaded - Too many sessions                     |

## Error response format

```json theme={null}
{
  "message": "Description of what went wrong",
  "detail": "Additional context about the error"
}
```

## Common errors

### Authentication (401)

```json theme={null}
{
  "message": "Authentication failed. Please check your credentials."
}
```

### Validation (422)

```json theme={null}
{
  "message": "Validation error",
  "detail": [
    {
      "loc": ["body", "url"],
      "msg": "field required",
      "type": "value_error.missing"
    }
  ]
}
```

### Execution errors

Returned when an operation fails. Includes the `x-error-class: NotteApiExecutionError` header.

```json theme={null}
{
  "message": "Error executing the requested operation"
}
```