Agent with Structured Outputs and Strict Tools

1from kern.agent import Agent
2from kern.models.anthropic import Claude
3from kern.tools import Function
4from pydantic import BaseModel
5
6class WeatherInfo(BaseModel):
7    """Structured output schema for weather information."""
8
9    location: str
10    temperature: float
11    unit: str
12    condition: str
13
14def get_weather(location: str, unit: str = "celsius") -> str:
15    temp = 72 if unit == "fahrenheit" else 22
16    return f"Weather in {location}: {temp}°{unit}, Sunny"
17
18# Create function with strict mode enabled
19weather_tool = Function(
20    name="get_weather",
21    description="Get current weather information for a location",
22    parameters={
23        "type": "object",
24        "properties": {
25            "location": {
26                "type": "string",
27                "description": "The city and state, e.g. San Francisco, CA",
28            },
29            "unit": {
30                "type": "string",
31                "enum": ["celsius", "fahrenheit"],
32                "description": "Temperature unit",
33            },
34        },
35        "required": ["location"],
36        "additionalProperties": False,
37    },
38    strict=True,  # Enable strict mode for validated tool parameters
39    entrypoint=get_weather,
40)
41
42# Agent with both structured outputs and strict tool
43agent = Agent(
44    model=Claude(id="claude-sonnet-4-5-20250929"),
45    tools=[weather_tool],
46    output_schema=WeatherInfo,
47    description="You help users get weather information.",
48)
49
50# The agent will use strict tool validation and return structured output
51agent.print_response("What's the weather like in San Francisco?")