# tinker_cookbook.tool_use

| Class                                                                                                                         | Description                                         |
| ----------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------- |
| [`ToolInput`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/toolinput/index.md)                     | Input to a tool invocation.                         |
| [`ToolResult`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/toolresult/index.md)                   | Result from a tool invocation.                      |
| [`types.Tool`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/types_tool/index.md)                   | Protocol for tools that can be used by LLM agents.  |
| [`FunctionTool`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/functiontool/index.md)               | A tool created from a decorated function or method. |
| [`AgentToolMessageEnv`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/agenttoolmessageenv/index.md) | Generic tool-use MessageEnv for agents.             |

| Function                                                                                                                          | Description                                                             |
| --------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- |
| [`simple_tool_result()`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/simple_tool_result/index.md)     | Helper function to create a ToolResult from content.                    |
| [`error_tool_result()`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/error_tool_result/index.md)       | Helper function to create an error ToolResult.                          |
| [`tools.tool()`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/tools_tool/index.md)                     | Decorator to create a tool from a function or method.                   |
| [`handle_tool_call()`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/handle_tool_call/index.md)         | Handle a single tool call, returning a ToolResult.                      |
| [`build_agent_tool_env()`](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/tool_use/build_agent_tool_env/index.md) | Convenience method to build an EnvFromMessageEnv for tool-using agents. |