Tool schema
Also known as: function schema · tool definition
A tool schema is the typed contract describing a tool an agent can call:
- The tool’s name and purpose.
- Its parameters: names, types, required/optional.
- What each parameter means.
The model reads the schema to decide how to call the tool; the harness validates the call before executing it.
Why quality matters: a vague schema produces vague calls. Clear names, tight types, and precise parameter descriptions measurably improve how reliably an agent uses a tool.