bind_tools

Example:

from langchain_anthropic import ChatAnthropic
from pydantic import BaseModel, Field

class GetWeather(BaseModel):
    '''Get the current weather in a given location'''

    location: str = Field(..., description="The city and state, e.g. San Francisco, CA")

class GetPrice(BaseModel):
    '''Get the price of a specific product.'''

    product: str = Field(..., description="The product to look up.")

model = ChatAnthropic(model="claude-sonnet-4-5-20250929", temperature=0)
model_with_tools = model.bind_tools([GetWeather, GetPrice])
model_with_tools.invoke(
    "What is the weather like in San Francisco",
)
# -> AIMessage(
#     content=[
#         {'text': '<thinking>\nBased on the user\'s question, the relevant function to call is GetWeather, which requires the "location" parameter.\n\nThe user has directly specified the location as "San Francisco". Since San Francisco is a well known city, I can reasonably infer they mean San Francisco, CA without needing the state specified.\n\nAll the required parameters are provided, so I can proceed with the API call.\n</thinking>', 'type': 'text'},
#         {'text': None, 'type': 'tool_use', 'id': 'toolu_01SCgExKzQ7eqSkMHfygvYuu', 'name': 'GetWeather', 'input': {'location': 'San Francisco, CA'}}
#     ],
#     response_metadata={'id': 'msg_01GM3zQtoFv8jGQMW7abLnhi', 'model': 'claude-sonnet-4-5-20250929', 'stop_reason': 'tool_use', 'stop_sequence': None, 'usage': {'input_tokens': 487, 'output_tokens': 145}},
#     id='run-87b1331e-9251-4a68-acef-f0a018b639cc-0'
# )