| 400 Bad Request | The request format is invalid or a required parameter is missing. | Check the JSON body, headers, and model name. |
| 401 Unauthorized | The API key is missing, invalid, or expired. | Verify Authorization: Bearer {{api_key}}. |
| 403 Forbidden | The API key does not have permission for this model or endpoint. | Check account permissions and model availability. |
| 404 Not Found | The endpoint or resource does not exist. | Confirm the request path and base URL. |
| 413 Payload Too Large | The request body is too large. | Reduce input size, file size, or token length. |
| 429 Too Many Requests | Rate limit or quota was exceeded. | Retry later, reduce concurrency, or review account limits. |
| 500 Internal Server Error | The provider or gateway returned an unexpected error. | Retry the request or contact support with the request ID. |
| 503 Service Unavailable | The upstream model provider is temporarily unavailable. | Retry later or switch to a fallback model. |