Agent handoffs

Agent handoffs use tools to update persistent state, allowing behavior or routing to change across turns. LangChain documents both middleware-based handoffs within one agent and graph-based handoffs between distinct agent nodes.

new Command({ goto: "agent_name", update: { messages: [...] } })

A Command that updates state and routes execution to a new step or agent.

import { createAgent, tool } from "langchain";
import { Command } from "@langchain/langgraph";
import { z } from "zod";

const transferToSupport = tool(
  () => new Command({
    goto: "support",
    update: {
      messages: [{ role: "tool", content: "Transferred to support", tool_call_id: "handoff" }],
    },
  }),
  {
    name: "transfer_to_support",
    description: "Transfer the conversation to the support agent",
    schema: z.object({}),
  },
);

const agent = createAgent({
  model: "openai:gpt-4.1-mini",
  tools: [transferToSupport],
});

await agent.invoke({ messages: [{ role: "user", content: "I need support" }] });

This illustrates a handoff tool returning Command to update state and route execution to another agent.