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

# UnprocessableEntityResponseError

Unprocessable Entity - Semantic validation failure

## Fields

| Field                 | Type                                                                                                      | Required             | Description                                | Example                                                        |
| --------------------- | --------------------------------------------------------------------------------------------------------- | -------------------- | ------------------------------------------ | -------------------------------------------------------------- |
| `error`               | [components.UnprocessableEntityResponseErrorData](../components/unprocessableentityresponseerrordata.mdx) | :heavy\_check\_mark: | Error data for UnprocessableEntityResponse | \{<br />"code": 422,<br />"message": "Invalid argument"<br />} |
| `openrouter_metadata` | Dict\[str, *Nullable\[Any]*]                                                                              | :heavy\_minus\_sign: | N/A                                        |                                                                |
| `user_id`             | *OptionalNullable\[str]*                                                                                  | :heavy\_minus\_sign: | N/A                                        |                                                                |