> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-7021d5f4.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ToolCustom - Go SDK

> ToolCustom type definition

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

## Fields

| Field          | Type                                                                                                               | Required             | Description                                                                                                                                                                                                 | Example                 |
| -------------- | ------------------------------------------------------------------------------------------------------------------ | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------- |
| `CacheControl` | [\*components.AnthropicCacheControlDirective](/client-sdks/go/api-reference/models/anthropiccachecontroldirective) | :heavy\_minus\_sign: | Enable automatic prompt caching. When set at the top level, the system automatically applies cache breakpoints to the last cacheable block in the request. Currently supported for Anthropic Claude models. | `{"type": "ephemeral"}` |
| `Description`  | `*string`                                                                                                          | :heavy\_minus\_sign: | N/A                                                                                                                                                                                                         |                         |
| `InputSchema`  | [components.InputSchema](/client-sdks/go/api-reference/models/inputschema)                                         | :heavy\_check\_mark: | N/A                                                                                                                                                                                                         |                         |
| `Name`         | `string`                                                                                                           | :heavy\_check\_mark: | N/A                                                                                                                                                                                                         |                         |
| `Type`         | [\*components.ToolTypeCustom](/client-sdks/go/api-reference/models/tooltypecustom)                                 | :heavy\_minus\_sign: | N/A                                                                                                                                                                                                         |                         |