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toolsCondition(
state: BaseMessage<MessageStructure<MessageToolSet>, MessageType>[] | StateType<__type>
):| Name | Type | Description |
|---|---|---|
state* | BaseMessage<MessageStructure<MessageToolSet>, MessageType>[] | StateType<__type> |
A conditional edge function that determines whether to route to a tools node or end the graph.
This function is designed to be used as a conditional edge in a LangGraph state graph to implement the common pattern of checking if an AI message contains tool calls that need to be executed.
The function checks the last message in the state for the presence of tool_calls.
If the message is an AIMessage with one or more tool calls, it returns "tools",
indicating that the graph should route to a tools node (typically a ToolNode) to
execute those tool calls. Otherwise, it returns END to terminate the graph execution.
This is a common pattern in agentic workflows where an AI model decides whether to use tools or provide a final response.
The current state of the graph, which can be either:
BaseMessage objects, where the last message is checked for tool callsMessagesAnnotation.State, which contains a messages arrayimport { StateGraph, MessagesAnnotation, END, START } from "@langchain/langgraph";
import { ToolNode, toolsCondition } from "@langchain/langgraph/prebuilt";
const graph = new StateGraph(MessagesAnnotation)
.addNode("agent", agentNode)
.addNode("tools", new ToolNode([searchTool, calculatorTool]))
.addEdge(START, "agent")
.addConditionalEdges("agent", toolsCondition, ["tools", END])
.addEdge("tools", "agent")
.compile();