> ## 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.

# MessagesOutputConfigFormat

A schema to specify Claude's output format in responses. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs).

## Fields

| Field     | Type                                                                                                  | Required             | Description |
| --------- | ----------------------------------------------------------------------------------------------------- | -------------------- | ----------- |
| `schema_` | Dict\[str, *Any*]                                                                                     | :heavy\_check\_mark: | N/A         |
| `type`    | [components.MessagesOutputConfigTypeJSONSchema](../components/messagesoutputconfigtypejsonschema.mdx) | :heavy\_check\_mark: | N/A         |