openrouter-function-calling

# OpenRouter Function Calling ## Overview OpenRouter supports OpenAI-compatible tool/function calling across multiple providers. Define tools as JSON Schema, send them with your request, and the model returns structured `tool_calls` instead of free text. This works with GPT-4o, Claude 3.5, Gemini, and other tool-capable models via the same API. The key difference from direct provider APIs: OpenRouter normalizes the tool calling interface, so the same code works across providers. ## Basic Tool Calling ```python import os, json from openai import OpenAI client = OpenAI( base_url="https://openrouter.ai/api/v1", api_key=os.environ["OPENROUTER_API_KEY"], default_headers={"HTTP-Referer": "https://my-app.com", "X-Title": "my-app"}, ) # Define tools with JSON Schema tools = [ { "type": "function", "function": { "name": "get_weather", "description": "Get current weather for a location", "parameters": { "type": "object", "properties": { "location": {"type": "string", "description": "City name"}, "unit": {"type": "string", "enum": ["celsius", "fahrenheit"]}, }, "required": ["location"], }, }, }, { "type": "function", "function": { "name": "search_database", "description": "Search the product database", "parameters": { ...