langgraph_cli_basic_stategraph_chatbot_quickstart.py

1from typing import Annotated
2from typing_extensions import TypedDict
3from langgraph.graph import StateGraph, START, END
4from langgraph.graph.message import add_messages
5
6# 1. Define the state of our graph
7class State(TypedDict):
8    # add_messages allows us to append new messages to the history
9    messages: Annotated[list, add_messages]
10
11# 2. Define a simple node function
12def chatbot(state: State):
13    return {"messages": [("assistant", "Hello! How can I help you today?")]}
14
15# 3. Build the graph
16workflow = StateGraph(State)
17
18# Add the chatbot node
19workflow.add_node("chatbot", chatbot)
20
21# Define the edges
22workflow.add_edge(START, "chatbot")
23workflow.add_edge("chatbot", END)
24
25# 4. Compile the graph
26graph = workflow.compile()
27
28# Note: To run this with langgraph-cli, you must have a langgraph.json 
29# in the same directory pointing to this variable:
30# {
31#   "graphs": {
32#     "agent": "./agent.py:graph"
33#   },
34#   "env": ".env"
35# }