> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-5b6e02fd.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# McpCallItem - Go SDK

> McpCallItem type definition

<Warning>
  The Go SDK and docs are currently in beta.
  Report issues on [GitHub](https://github.com/OpenRouterTeam/go-sdk/issues).
</Warning>

An MCP tool call with its output or error

## Fields

| Field         | Type                                                                               | Required             | Description |
| ------------- | ---------------------------------------------------------------------------------- | -------------------- | ----------- |
| `Arguments`   | `string`                                                                           | :heavy\_check\_mark: | N/A         |
| `Error`       | optionalnullable.OptionalNullable\[`string`]                                       | :heavy\_minus\_sign: | N/A         |
| `ID`          | `string`                                                                           | :heavy\_check\_mark: | N/A         |
| `Name`        | `string`                                                                           | :heavy\_check\_mark: | N/A         |
| `Output`      | optionalnullable.OptionalNullable\[`string`]                                       | :heavy\_minus\_sign: | N/A         |
| `ServerLabel` | `string`                                                                           | :heavy\_check\_mark: | N/A         |
| `Type`        | [components.McpCallItemType](/client-sdks/go/api-reference/models/mcpcallitemtype) | :heavy\_check\_mark: | N/A         |