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agents-and-tools/tool-use/define-tools

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2121 
2222## Specifying client tools
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24Client tools (both Anthropic-schema and user-defined) are specified in the `tools` top-level parameter of the API request. Each tool definition includes:
24Client tools are specified in the `tools` top-level parameter of the API request. Anthropic-schema client tools, such as the bash and text editor tools, are declared by a date-versioned `type`; see each tool's page, linked from the [Tool reference](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference), for the fields it accepts. The computer use and browser use tools are [client toolsets](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference#client-toolsets): a single entry with no `name` that declares a fixed set of member tools. A user-defined tool definition includes:
2525 
2626| Parameter | Description |
2727| ---------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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3030| `input_schema` | A [JSON Schema](https://json-schema.org/) object defining the expected parameters for the tool. |
3131| `input_examples` | (Optional) An array of example input objects to help Claude understand how to use the tool. See [Providing tool use examples](https://platform.claude.com/docs/en/agents-and-tools/tool-use/define-tools#providing-tool-use-examples). |
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33For the full set of optional properties available on any tool definition, including `cache_control`, `strict`, `defer_loading`, and `allowed_callers`, see the [Tool reference](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference#tool-definition-properties).
33For the full set of optional properties available on any single tool definition, including `cache_control`, `strict`, `defer_loading`, and `allowed_callers`, see the [Tool reference](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference#tool-definition-properties). A client toolset entry accepts `cache_control` and `allowed_callers` on the entry and sets `defer_loading` per member; see [Client toolsets](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference#client-toolsets).
3434 
3535<Accordion title="Example simple tool definition">
3636 ```json JSON
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551551### Requirements and limitations
552552 
553553* **Schema validation** - Each example must be valid according to the tool's `input_schema`. Invalid examples return a 400 error
554* **Not supported for server-side tools** - Input examples work on user-defined and Anthropic-schema client tools, but not on server tools such as web search or code execution
554* **Not supported for server-side tools or client toolsets** - Input examples work on user-defined and Anthropic-schema client tools other than the [computer use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-tool) and [browser use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/browser-use-tool) toolsets, but not on server tools such as web search or code execution
555555* **Token cost** - Examples add to prompt tokens: \~20–50 tokens for simple examples, \~100–200 tokens for complex nested objects
556556 
557557## Controlling Claude's output