> ## 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.

# MessagesMessageParam

Anthropic message with OpenRouter extensions

## Fields

| Field           | Type                                                                                                          | Required             | Description | Example                        |
| --------------- | ------------------------------------------------------------------------------------------------------------- | -------------------- | ----------- | ------------------------------ |
| `clear_at`      | [OptionalNullable\[components.AnthropicSystemClearAt\]](../components/anthropicsystemclearat.mdx)             | :heavy\_minus\_sign: | N/A         | next\_user\_message            |
| `content`       | [components.MessagesMessageParamContentUnion5](../components/messagesmessageparamcontentunion5.mdx)           | :heavy\_check\_mark: | N/A         |                                |
| `output_config` | [OptionalNullable\[components.AnthropicMessageOutputConfig\]](../components/anthropicmessageoutputconfig.mdx) | :heavy\_minus\_sign: | N/A         | \{<br />"effort": "low"<br />} |
| `role`          | [components.MessagesMessageParamRole](../components/messagesmessageparamrole.mdx)                             | :heavy\_check\_mark: | N/A         |                                |