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import os
from dotenv import load_dotenv
from langchain.chat_models import init_chat_model
from langchain_core.messages import SystemMessage, ToolMessage
from langchain_core.tools import tool
from langgraph.graph import (
END,
START,
MessagesState,
StateGraph,
)
from typing_extensions import Literal
from azure.identity import DefaultAzureCredential, get_bearer_token_provider
from azure.ai.agentserver.langgraph import from_langgraph
load_dotenv()
deployment_name = os.getenv("AZURE_OPENAI_CHAT_DEPLOYMENT_NAME", "gpt-4o")
api_key = os.getenv("AZURE_OPENAI_API_KEY", "")
if api_key:
llm = init_chat_model(f"azure_openai:{deployment_name}")
else:
credential = DefaultAzureCredential()
token_provider = get_bearer_token_provider(
credential, "https://cognitiveservices.azure.com/.default"
)
llm = init_chat_model(
f"azure_openai:{deployment_name}",
azure_ad_token_provider=token_provider,
)
# Define tools
@tool
def multiply(a: int, b: int) -> int:
"""Multiply a and b.
Args:
a: first int
b: second int
"""
return a * b
@tool
def add(a: int, b: int) -> int:
"""Adds a and b.
Args:
a: first int
b: second int
"""
return a + b
@tool
def divide(a: int, b: int) -> float:
"""Divide a and b.
Args:
a: first int
b: second int
"""
return a / b
# Augment the LLM with tools
tools = [add, multiply, divide]
tools_by_name = {tool.name: tool for tool in tools}
llm_with_tools = llm.bind_tools(tools)
# Nodes
def llm_call(state: MessagesState):
"""LLM decides whether to call a tool or not"""
return {
"messages": [
llm_with_tools.invoke(
[
SystemMessage(
content="You are a helpful assistant tasked with performing arithmetic on a set of inputs."
)
]
+ state["messages"]
)
]
}
def tool_node(state: dict):
"""Performs the tool call"""
result = []
for tool_call in state["messages"][-1].tool_calls:
tool = tools_by_name[tool_call["name"]]
observation = tool.invoke(tool_call["args"])
result.append(ToolMessage(content=observation, tool_call_id=tool_call["id"]))
return {"messages": result}
# Conditional edge function to route to the tool node or end based upon whether the LLM made a tool call
def should_continue(state: MessagesState) -> Literal["environment", END]:
"""Decide if we should continue the loop or stop based upon whether the LLM made a tool call"""
messages = state["messages"]
last_message = messages[-1]
# If the LLM makes a tool call, then perform an action
if last_message.tool_calls:
return "Action"
# Otherwise, we stop (reply to the user)
return END
# Build workflow
agent_builder = StateGraph(MessagesState)
# Add nodes
agent_builder.add_node("llm_call", llm_call)
agent_builder.add_node("environment", tool_node)
# Add edges to connect nodes
agent_builder.add_edge(START, "llm_call")
agent_builder.add_conditional_edges(
"llm_call",
should_continue,
{
"Action": "environment",
END: END,
},
)
agent_builder.add_edge("environment", "llm_call")
# Compile the agent
agent = agent_builder.compile()
if __name__ == "__main__":
adapter = from_langgraph(agent)
adapter.run()
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