A tool is a method the model can call during a chat. Use a shipped toolkit, write your own @Tool class, or define a tool at runtime.

Actions and tools: choose between an action, a @Tool class, a built-in toolkit and an MCP tool.
Catalog: the 63 shipped toolkits and their tools.
Custom tools: write a class with @Tool methods and set per-tool deadlines.
Register tools: register toolkits and runtime-defined tools, and filter or observe tool calls.
Idempotency: make retries of side-effecting tools safe.
Examples: attach example calls with @ToolExample.
Images and speech: image generation, text-to-speech and speech-to-text toolkits.
Docling: convert documents through a Docling MCP server or the Docling CLI.
Graph stores: the knowledge-graph toolkit as a retrieval backend.

For tools from MCP servers, see MCP client.

Tools