OpenAI Function Schema Generator
Build valid JSON schemas for GPT-4 function calling instantly. No more syntax errors or missing brackets.
Function Definition
Parameters
JSON Schema Output
Why Use Function Calling?
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Connect APIs
Turn GPT-4 into an agent that can fetch real-time data, send emails, or query your database by defining tools.
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Structured Data Extraction
Force the AI to output perfect JSON data (e.g., extracting names and dates from a resume) instead of unstructured text.
Guide: Writing Better Schemas
Function calling is the bridge between the "Brain" (LLM) and the "Hands" (Your Code). The quality of your schema directly affects how well the AI uses your tool.
We have written a comprehensive guide on how to master this: The Developer's Handbook to OpenAI Function Calling.
Quick Best Practices
- Descriptive Names: Use `get_weather_current` instead of just `get`.
- Detailed Descriptions: Don't just say "The location". Say "The city and state, e.g. San Francisco, CA". This acts as a prompt for the model.
- Use Enums: Strict control over output values prevents hallucinations.