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https://github.com/langchain-ai/langgraph.git
synced 2026-10-21 07:21:44 +02:00
Eugene YurtsevandGitHub
50601dc02c
* Add structured output tools to ToolNode
* Fix default tool node name to match the actual default ('tools')
* Update doc-strings to explain what inputs/outputs are for the ToolNode.
* Mark internal attributes as private (potentially breaking -- although hopefully users aren't accessing these)
## Decisions points
* OK with two properties? Done since users may be relying on
`tools_by_name` and expanding the return type will break user code.
## Changes in public/private interface
### Marked as public
* Make `tools_by_name` an official public property
* Make `structured_output_tools` a public property
### Marked as private
There should be no reason why users are accessing these attributes
```python
_tool_to_state_args
_tool_to_store_arg
_handle_tool_errors
_messages_key
```
### Usage
```python
class OutputSchema(BaseModel):
name: str
age: int
location: str
tool_node = ToolNode([OutputSchema])
# Test that the structured output tool is registered correctly
assert "OutputSchema" in tool_node.structured_output_tools
# Create a tool call that matches the schema
tool_call = {
"name": "OutputSchema",
"args": {"name": "Alice", "age": 30, "location": "NYC"},
"id": "call_123",
"type": "tool_call",
}
# Test sync execution
result = tool_node.invoke(
{"messages": [AIMessage(content="", tool_calls=[tool_call])]}
)
# Should return a Command with structured response
assert isinstance(result, list)
assert len(result) == 1
command = result[0]
assert isinstance(command, Command)
# Check the update structure
assert "messages" in command.update
assert "structured_response" in command.update
# Check the tool message
tool_message = command.update["messages"][0]
assert isinstance(tool_message, ToolMessage)
assert tool_message.name == "OutputSchema"
assert tool_message.tool_call_id == "call_123"
# Check the structured response
structured_response = command.update["structured_response"]
assert isinstance(structured_response, OutputSchema)
assert structured_response.name == "Alice"
assert structured_response.age == 30
assert structured_response.location == "NYC"
```
LangGraph Prebuilt
This library defines high-level APIs for creating and executing LangGraph agents and tools.
Important
This library is meant to be bundled with
langgraph, don't install it directly
Agents
langgraph-prebuilt provides an implementation of a tool-calling ReAct-style agent - create_react_agent:
pip install langchain-anthropic
from langchain_anthropic import ChatAnthropic
from langgraph.prebuilt import create_react_agent
# Define the tools for the agent to use
def search(query: str):
"""Call to surf the web."""
# This is a placeholder, but don't tell the LLM that...
if "sf" in query.lower() or "san francisco" in query.lower():
return "It's 60 degrees and foggy."
return "It's 90 degrees and sunny."
tools = [search]
model = ChatAnthropic(model="claude-3-7-sonnet-latest")
app = create_react_agent(model, tools)
# run the agent
app.invoke(
{"messages": [{"role": "user", "content": "what is the weather in sf"}]},
)
Tools
ToolNode
langgraph-prebuilt provides an implementation of a node that executes tool calls - ToolNode:
from langgraph.prebuilt import ToolNode
from langchain_core.messages import AIMessage
def search(query: str):
"""Call to surf the web."""
# This is a placeholder, but don't tell the LLM that...
if "sf" in query.lower() or "san francisco" in query.lower():
return "It's 60 degrees and foggy."
return "It's 90 degrees and sunny."
tool_node = ToolNode([search])
tool_calls = [{"name": "search", "args": {"query": "what is the weather in sf"}, "id": "1"}]
ai_message = AIMessage(content="", tool_calls=tool_calls)
# execute tool call
tool_node.invoke({"messages": [ai_message]})
ValidationNode
langgraph-prebuilt provides an implementation of a node that validates tool calls against a pydantic schema - ValidationNode:
from pydantic import BaseModel, field_validator
from langgraph.prebuilt import ValidationNode
from langchain_core.messages import AIMessage
class SelectNumber(BaseModel):
a: int
@field_validator("a")
def a_must_be_meaningful(cls, v):
if v != 37:
raise ValueError("Only 37 is allowed")
return v
validation_node = ValidationNode([SelectNumber])
validation_node.invoke({
"messages": [AIMessage("", tool_calls=[{"name": "SelectNumber", "args": {"a": 42}, "id": "1"}])]
})
Agent Inbox
The library contains schemas for using the Agent Inbox with LangGraph agents. Learn more about how to use Agent Inbox here.
from langgraph.types import interrupt
from langgraph.prebuilt.interrupt import HumanInterrupt, HumanResponse
def my_graph_function():
# Extract the last tool call from the `messages` field in the state
tool_call = state["messages"][-1].tool_calls[0]
# Create an interrupt
request: HumanInterrupt = {
"action_request": {
"action": tool_call['name'],
"args": tool_call['args']
},
"config": {
"allow_ignore": True,
"allow_respond": True,
"allow_edit": False,
"allow_accept": False
},
"description": _generate_email_markdown(state) # Generate a detailed markdown description.
}
# Send the interrupt request inside a list, and extract the first response
response = interrupt([request])[0]
if response['type'] == "response":
# Do something with the response
...