Definition
Full definition of tool use
You give the model a schema of available tools (e.g., search_database, send_email, create_task). The model returns tool_use blocks when it wants to call one. You execute the call and feed the result back as tool_result, then the model continues. OpenAI calls this "function calling"; Anthropic calls it "tool use"; same concept. Powers agents, dynamic workflows, and integration with real systems.
In practice
Tool Use examples
Tool definition
name: search_orders, description: 'Search orders by customer email', input_schema: {email: string}
Used by
Apps that exemplify tool use
See tool use in action across real integrations.
FAQ
Common questions about tool use
How many tools can I give an LLM?
5-10 is the sweet spot. More and the model gets confused about which to call. Group related tools or use namespacing.
What if the model picks the wrong tool?
Improve tool descriptions — that's mostly what the model uses to decide. Add examples in the system prompt.
