Models & inference

Tool format

The JSON shape a provider expects for tool definitions and tool calls. Differs slightly per provider.

also known as: tool schema, function schema

In depth

Anthropic, OpenAI, Mistral, and Gemini all support tool calling, but the schemas they expect are not byte-identical. Most agent runtimes normalise across them, so your YAML declares one tool and the runtime translates per provider. Mismatches usually surface as 'the tool ran but the model thinks it didn't', which is a sign that the result format is off by a field name.

Related concepts

Tool useThe LLM capability to emit a structured call to an external function, which the runtime executes and feeds back as context.Function callingOpenAI's term for tool use. Same concept, slightly different format.

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