Your files stay on your device

# Function calling schema builder

Define an LLM tool once with a one line field syntax and export it in the exact shapes OpenAI, Anthropic and Gemini expect, with per provider validation findings.

Name the tool and add parameters to see the provider exports.

The provider rules here are a dated snapshot of each API's documented limits, and Gemini is checked conservatively. A valid schema tells the API to accept the tool; it says nothing about whether a model picks the tool or fills it in sensibly. Treat every returned argument as untrusted input on your server.
Options

## More AI tools

- [JSON schema validator](/json/schema)
- [Fine-tune JSONL formatter](/ai/jsonl-formatter)
- [Eval dataset builder](/ai/ai-evaluation-dataset-builder)
[All AI tools](/ai)

Was this tool useful?
YesNo

---

Canonical HTML: https://nutter.tools/ai/function-calling-schema-builder
Markdown version: https://nutter.tools/ai/function-calling-schema-builder.md
Plain-text version: https://nutter.tools/ai/function-calling-schema-builder.txt
Agent index: https://nutter.tools/llms.txt