如何在多代理应用程序中添加多轮对话¶
在本指南中，我们将构建一个应用程序，允许最终用户与一个或多个代理进行*多轮对话*。我们将创建一个节点，该节点使用一个中断来收集用户输入，并返回到**活动**代理。
代理将作为图中的节点实现，执行代理步骤并确定下一步行动：
- **等待用户输入**以继续对话，或
- 路由到另一个代理（或返回自身，例如在循环中）通过交接。
def human(state: MessagesState) -> Command[Literal["agent", "another_agent"]]:
"""一个用于收集用户输入的节点。"""
user_input = interrupt(value="Ready for user input.")
# 确定活动代理。
active_agent = ...
...
return Command(
update={
"messages": [{
"role": "human",
"content": user_input,
}]
},
goto=active_agent
)
def agent(state) -> Command[Literal["agent", "another_agent", "human"]]:
# 路由/停止的条件可以是任何内容，例如 LLM 工具调用/结构化输出等。
goto = get_next_agent(...) # 'agent' / 'another_agent'
if goto:
return Command(goto=goto, update={"my_state_key": "my_state_value"})
else:
return Command(goto="human") # 转到 human 节点
设置环境¶
首先，让我们安装所需的包
import getpass
import os
def _set_env(var: str):
if not os.environ.get(var):
os.environ[var] = getpass.getpass(f"{var}: ")
_set_env("ANTHROPIC_API_KEY")
为LangGraph开发设置LangSmith
注册LangSmith，可以快速发现并解决您的LangGraph项目中的问题，提高项目性能。LangSmith允许您使用跟踪数据来调试、测试和监控使用LangGraph构建的LLM应用程序——更多关于如何开始的信息，请参阅这里。
定义代理¶
在这个示例中，我们将创建一个旅行助手代理团队，这些代理能够通过交接来互相通信。
我们将创建两个代理：
travel_advisor：能够帮助推荐旅行目的地。可以请求hotel_advisor的帮助。hotel_advisor：能够帮助推荐酒店。可以请求travel_advisor的帮助。
我们将使用预构建的create_react_agent来创建这些代理——每个代理将具有特定于其专业领域的工具，以及一个用于与其他代理交接的特殊工具。
首先，让我们定义将要使用的工具：
import random
from typing import Annotated, Literal
from langchain_core.tools import tool
from langchain_core.tools.base import InjectedToolCallId
from langgraph.prebuilt import InjectedState
@tool
def get_travel_recommendations():
"""Get recommendation for travel destinations"""
return random.choice(["aruba", "turks and caicos"])
@tool
def get_hotel_recommendations(location: Literal["aruba", "turks and caicos"]):
"""Get hotel recommendations for a given destination."""
return {
"aruba": [
"The Ritz-Carlton, Aruba (Palm Beach)"
"Bucuti & Tara Beach Resort (Eagle Beach)"
],
"turks and caicos": ["Grace Bay Club", "COMO Parrot Cay"],
}[location]
def make_handoff_tool(*, agent_name: str):
"""Create a tool that can return handoff via a Command"""
tool_name = f"transfer_to_{agent_name}"
@tool(tool_name)
def handoff_to_agent(
state: Annotated[dict, InjectedState],
tool_call_id: Annotated[str, InjectedToolCallId],
):
"""Ask another agent for help."""
tool_message = {
"role": "tool",
"content": f"Successfully transferred to {agent_name}",
"name": tool_name,
"tool_call_id": tool_call_id,
}
return Command(
# navigate to another agent node in the PARENT graph
goto=agent_name,
graph=Command.PARENT,
# This is the state update that the agent `agent_name` will see when it is invoked.
# We're passing agent's FULL internal message history AND adding a tool message to make sure
# the resulting chat history is valid.
update={"messages": state["messages"] + [tool_message]},
)
return handoff_to_agent
API Reference: tool | InjectedToolCallId | InjectedState
现在让我们使用预构建的create_react_agent来创建我们的代理。我们还将定义一个专门的human节点，并使用interrupt，在代理的最终响应之后，我们将路由到此节点。请注意，为了实现这一点，我们将每个代理调用包装在一个单独的节点函数中，该函数返回Command(goto="human", ...)。
from langchain_anthropic import ChatAnthropic
from langgraph.graph import MessagesState, StateGraph, START
from langgraph.prebuilt import create_react_agent, InjectedState
from langgraph.types import Command, interrupt
from langgraph.checkpoint.memory import MemorySaver
model = ChatAnthropic(model="claude-3-5-sonnet-latest")
# Define travel advisor tools and ReAct agent
travel_advisor_tools = [
get_travel_recommendations,
make_handoff_tool(agent_name="hotel_advisor"),
]
travel_advisor = create_react_agent(
model,
travel_advisor_tools,
prompt=(
"You are a general travel expert that can recommend travel destinations (e.g. countries, cities, etc). "
"If you need hotel recommendations, ask 'hotel_advisor' for help. "
"You MUST include human-readable response before transferring to another agent."
),
)
def call_travel_advisor(
state: MessagesState,
) -> Command[Literal["hotel_advisor", "human"]]:
# You can also add additional logic like changing the input to the agent / output from the agent, etc.
# NOTE: we're invoking the ReAct agent with the full history of messages in the state
response = travel_advisor.invoke(state)
return Command(update=response, goto="human")
# Define hotel advisor tools and ReAct agent
hotel_advisor_tools = [
get_hotel_recommendations,
make_handoff_tool(agent_name="travel_advisor"),
]
hotel_advisor = create_react_agent(
model,
hotel_advisor_tools,
prompt=(
"You are a hotel expert that can provide hotel recommendations for a given destination. "
"If you need help picking travel destinations, ask 'travel_advisor' for help."
"You MUST include human-readable response before transferring to another agent."
),
)
def call_hotel_advisor(
state: MessagesState,
) -> Command[Literal["travel_advisor", "human"]]:
response = hotel_advisor.invoke(state)
return Command(update=response, goto="human")
def human_node(
state: MessagesState, config
) -> Command[Literal["hotel_advisor", "travel_advisor", "human"]]:
"""A node for collecting user input."""
user_input = interrupt(value="Ready for user input.")
# identify the last active agent
# (the last active node before returning to human)
langgraph_triggers = config["metadata"]["langgraph_triggers"]
if len(langgraph_triggers) != 1:
raise AssertionError("Expected exactly 1 trigger in human node")
active_agent = langgraph_triggers[0].split(":")[1]
return Command(
update={
"messages": [
{
"role": "human",
"content": user_input,
}
]
},
goto=active_agent,
)
builder = StateGraph(MessagesState)
builder.add_node("travel_advisor", call_travel_advisor)
builder.add_node("hotel_advisor", call_hotel_advisor)
# This adds a node to collect human input, which will route
# back to the active agent.
builder.add_node("human", human_node)
# We'll always start with a general travel advisor.
builder.add_edge(START, "travel_advisor")
checkpointer = MemorySaver()
graph = builder.compile(checkpointer=checkpointer)
API Reference: ChatAnthropic | StateGraph | START | create_react_agent | InjectedState | Command | interrupt | MemorySaver
测试多轮对话¶
让我们用这个应用程序测试一个多轮对话。
import uuid
thread_config = {"configurable": {"thread_id": uuid.uuid4()}}
inputs = [
# 1st round of conversation,
{
"messages": [
{"role": "user", "content": "i wanna go somewhere warm in the caribbean"}
]
},
# Since we're using `interrupt`, we'll need to resume using the Command primitive.
# 2nd round of conversation,
Command(
resume="could you recommend a nice hotel in one of the areas and tell me which area it is."
),
# 3rd round of conversation,
Command(
resume="i like the first one. could you recommend something to do near the hotel?"
),
]
for idx, user_input in enumerate(inputs):
print()
print(f"--- Conversation Turn {idx + 1} ---")
print()
print(f"User: {user_input}")
print()
for update in graph.stream(
user_input,
config=thread_config,
stream_mode="updates",
):
for node_id, value in update.items():
if isinstance(value, dict) and value.get("messages", []):
last_message = value["messages"][-1]
if isinstance(last_message, dict) or last_message.type != "ai":
continue
print(f"{node_id}: {last_message.content}")
--- Conversation Turn 1 ---
User: {'messages': [{'role': 'user', 'content': 'i wanna go somewhere warm in the caribbean'}]}
travel_advisor: Based on the recommendations, I suggest considering Aruba! It's a fantastic Caribbean destination known for its perfect warm weather year-round, with average temperatures around 82°F (28°C). Aruba is famous for its pristine white-sand beaches, crystal-clear waters, and constant cooling trade winds.
Some highlights of Aruba include:
1. Beautiful Eagle Beach and Palm Beach
2. Excellent snorkeling and diving opportunities
3. Vibrant culture and dining scene
4. Consistent sunny weather (it's outside the hurricane belt!)
5. Great shopping and nightlife in Oranjestad
Would you like me to help you explore more specific aspects of visiting Aruba? Or if you're interested in finding a hotel there, I can connect you with our hotel advisor who can provide detailed accommodation recommendations.
--- Conversation Turn 2 ---
User: Command(resume='could you recommend a nice hotel in one of the areas and tell me which area it is.')
hotel_advisor: Based on the recommendations, I can suggest two excellent options in different areas:
1. The Ritz-Carlton, Aruba - Located in Palm Beach
This luxury resort is situated in the bustling Palm Beach area, known for its high-rise hotels and vibrant atmosphere. The Ritz offers world-class amenities, including a luxurious spa, multiple restaurants, and a casino. The location is perfect if you want to be close to shopping, dining, and nightlife.
2. Bucuti & Tara Beach Resort - Located in Eagle Beach
This adults-only boutique resort is situated on the stunning Eagle Beach, which is wider and generally quieter than Palm Beach. It's perfect for those seeking a more peaceful, romantic atmosphere. The resort is known for its exceptional service and sustainability practices.
Would you like more specific information about either of these hotels or their locations?
--- Conversation Turn 3 ---
User: Command(resume='i like the first one. could you recommend something to do near the hotel?')
travel_advisor: Near The Ritz-Carlton in Palm Beach, there are several excellent activities you can enjoy:
1. Palm Beach Strip - Right outside the hotel, you can walk along this vibrant strip featuring:
- High-end shopping at luxury boutiques
- Various restaurants and bars
- The Paseo Herencia Shopping & Entertainment Center
2. Water Activities (within walking distance):
- Snorkeling at the artificial reef
- Parasailing
- Jet ski rentals
- Catamaran sailing trips
- Paddleboarding
3. Nearby Attractions:
- Bubali Bird Sanctuary (5-minute drive)
- Butterfly Farm (10-minute walk)
- California Lighthouse (short drive)
- Visit the famous Stellaris Casino (located within the Ritz-Carlton)
4. Local Culture:
- Visit the nearby fishing pier
- Take a short trip to local craft markets
- Evening sunset watching on the beach
Would you like more specific information about any of these activities? I can also recommend some specific restaurants or shopping venues in the area!