langgraph-agent-interrupt-1-reject-node.js

#!/usr/bin/env node
import { ToolNode } from '@langchain/langgraph/prebuilt';
import {
  StateGraph,
  MessagesAnnotation,
  MemorySaver,
  START,
  END,
  interrupt,
  Command,
} from '@langchain/langgraph';

import { createInstance as llmCreateInstance } from './api/openrouter-openai.js';
import { AIMessage, HumanMessage, SystemMessage } from '@langchain/core/messages';
import { tool } from '@langchain/core/tools';
import { z } from 'zod';

/**
 * PLACEHOLDER TOOLS
 */
const cmdFooTool = tool(async function(inputs) {
  console.log('===TOOL CMD_FOO===');
  return inputs.name;
}, {
  name: 'CMD_FOO',
  description: 'Invoke when you want to do a Foo.',
  schema: z.object({
    name: z.string('Any string'),
  }),
});
const cmdBarTool = tool(async function(inputs) {
  console.log('===TOOL QRY_BAR===');
  return inputs.name;
}, {
  name: 'QRY_BAR',
  description: 'Invoke when you want to query a Bar.',
  schema: z.object({
    name: z.string('Any string'),
  }),
});
const tools = [cmdFooTool, cmdBarTool];
const llm = llmCreateInstance();
const llmWithTools = llm.bindTools(tools);
const toolsNode = new ToolNode(tools);

async function agentNode(state) {
  console.log('===AGENT NODE===');
  const response = await llmWithTools.invoke(state.messages);
  console.log('=AGENT RESPONSE=',
    '\ncontent:', response.content,
    '\ntool_calls:', response.tool_calls.map((toolCall) => (toolCall.name)));
  return { messages: [response] };
}

async function rejectNode(state) {
  console.log('===REJECT NODE===');
  const rejectionMessage = new AIMessage({
    content: 'Tool calls were rejected by user',
    tool_calls: [],
  });
  return {
    messages: [
      ...state.messages,
      rejectionMessage,
    ]
  };
}

async function approveNode (state) {
  console.log('===APPROVE NODE===');
  const lastMsg = state.messages.at(-1);
  const toolCall = lastMsg.tool_calls.at(-1);

  const interruptMessage = `Please review the following tool invocation:
${toolCall.name} with inputs ${JSON.stringify(toolCall.args, undefined, 2)}
Do you approve (y/N)`;

  console.log('=APPROVE INTERRUPT PRE=');
  const interruptResponse = interrupt(interruptMessage);
  console.log('=APPROVE INTERRUPT POST=');

  const isApproved = (interruptResponse.trim().charAt(0).toLowerCase() === 'y');
  const goto = (isApproved) ? 'tools' : 'reject';
  console.log('=APPROVE RESULT=\n', { isApproved, goto });
  return new Command({ goto });
}

function hasToolCalls(message) {
  return message?.tool_calls?.length > 0;
}

async function agentRouter (state) {
  const lastMsg = state.messages.at(-1);
  if (hasToolCalls(lastMsg)) {
    return 'approve';
  }
  return END;
}

const workflow = new StateGraph(MessagesAnnotation)
  .addNode('agent', agentNode)
  .addNode('tools', toolsNode)
  .addNode('reject', rejectNode)
  .addNode('approve', approveNode, {
    ends: ['tools', 'reject'],
  })
  .addEdge(START, 'agent')
  .addEdge('tools', 'agent')
  .addEdge('reject', END)
  .addConditionalEdges('agent', agentRouter, ['approve', END]);

const checkpointer = new MemorySaver();
const graph = workflow.compile({
  checkpointer,
});
const graphConfig = {
  configurable: { thread_id: '0x0004' },
};

/**
 * SIMULATE A RUN
 */
let state;
let agentResult;
let inputText;
let invokeWith;

// step 1: prompt
inputText = 'Pls perform a Foo with name "ASDF".';
console.log('===HUMAN PROMPT (1)===\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (1)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 2: interrupted in the 'approve' node, human in the loop authorises
inputText = 'yes'
console.log('===HUMAN INTERRUPT RESPONSE (2)===\n', inputText);
invokeWith = new Command({ resume: inputText });
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (2)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 3: prompt
inputText = 'Pls perform a Foo with name "ZXCV".';
console.log('===HUMAN PROMPT (3)===\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT=== (3)\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 4: interrupted in the 'approve' node, human in the loop does not authorise
inputText = 'no';
console.log('===HUMAN INTERRUPT RESPONSE (4)===\n', inputText);
invokeWith = new Command({ resume: inputText });
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT=== (4)\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 5: prompt
inputText = 'Pls perform a Foo with name "GHJK".';
console.log('===HUMAN PROMPT=== (5)\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (6)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

langgraph-agent-interrupt-2-update-tool-call.js

#!/usr/bin/env node
import { ToolNode } from '@langchain/langgraph/prebuilt';
import {
  StateGraph,
  MessagesAnnotation,
  MemorySaver,
  START,
  END,
  interrupt,
  Command,
} from '@langchain/langgraph';

import { createInstance as llmCreateInstance } from './api/openrouter-openai.js';
import { AIMessage, HumanMessage, SystemMessage } from '@langchain/core/messages';
import { tool } from '@langchain/core/tools';
import { z } from 'zod';

/**
 * PLACEHOLDER TOOLS
 */
const cmdFooTool = tool(async function(inputs) {
  console.log('===TOOL CMD_FOO===');
  return inputs.name;
}, {
  name: 'CMD_FOO',
  description: 'Invoke when you want to do a Foo.',
  schema: z.object({
    name: z.string('Any string'),
  }),
});
const cmdBarTool = tool(async function(inputs) {
  console.log('===TOOL QRY_BAR===');
  return inputs.name;
}, {
  name: 'QRY_BAR',
  description: 'Invoke when you want to query a Bar.',
  schema: z.object({
    name: z.string('Any string'),
  }),
});
const tools = [cmdFooTool, cmdBarTool];
const llm = llmCreateInstance();
const llmWithTools = llm.bindTools(tools);
const toolsNode = new ToolNode(tools);

async function agentNode(state) {
  console.log('===AGENT NODE===');
  const response = await llmWithTools.invoke(state.messages);
  console.log('=AGENT RESPONSE=',
    '\ncontent:', response.content,
    '\ntool_calls:', response.tool_calls.map((toolCall) => (toolCall.name)));
  return { messages: [response] };
}

async function approveNode (state) {
  console.log('===APPROVE NODE===');
  const lastMsg = state.messages.at(-1);
  const toolCall = lastMsg.tool_calls.at(-1);

  const interruptMessage = `Please review the following tool invocation:
${toolCall.name} with inputs ${JSON.stringify(toolCall.args, undefined, 2)}
Do you approve (y/N)`;

  console.log('=APPROVE INTERRUPT PRE=');
  const interruptResponse = interrupt(interruptMessage);
  console.log('=APPROVE INTERRUPT POST=');

  const isApproved = (interruptResponse.trim().charAt(0).toLowerCase() === 'y');
  if (isApproved) {
    return new Command({
      goto: 'tools',
    });
  } else {
    // Create a new message for rejection and clear tool calls,
    // so that it does not get passed to the next graph node.
    const rejectionMessage = new AIMessage({
      content: 'Tool calls were rejected by user',
      tool_calls: [],
    });
    return {
      messages: [...state.messages, rejectionMessage],
      goto: END,
    };
  }
}

function hasToolCalls(message) {
  return message?.tool_calls?.length > 0;
}

async function agentRouter (state) {
  const lastMsg = state.messages.at(-1);
  if (hasToolCalls(lastMsg)) {
    return 'approve';
  }
  return END;
}

const workflow = new StateGraph(MessagesAnnotation)
  .addNode('agent', agentNode)
  .addNode('tools', toolsNode)
  .addNode('approve', approveNode, {
    ends: ['tools', END],
  })
  .addEdge(START, 'agent')
  .addEdge('tools', 'agent')
  .addConditionalEdges('agent', agentRouter, ['approve', END]);

const checkpointer = new MemorySaver();
const graph = workflow.compile({
  checkpointer,
});
const graphConfig = {
  configurable: { thread_id: '0x0004' },
};

/**
 * SIMULATE A RUN
 */
let state;
let agentResult;
let inputText;
let invokeWith;

// step 1: prompt
inputText = 'Pls perform a Foo with name "ASDF".';
console.log('===HUMAN PROMPT (1)===\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (1)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 2: interrupted in the 'approve' node, human in the loop authorises
inputText = 'yes'
console.log('===HUMAN INTERRUPT RESPONSE (2)===\n', inputText);
invokeWith = new Command({ resume: inputText });
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (2)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 3: prompt
inputText = 'Pls perform a Foo with name "ZXCV".';
console.log('===HUMAN PROMPT (3)===\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT=== (3)\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 4: interrupted in the 'approve' node, human in the loop does not authorise
inputText = 'no';
console.log('===HUMAN INTERRUPT RESPONSE (4)===\n', inputText);
invokeWith = new Command({ resume: inputText });
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT=== (4)\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);

// step 5: prompt
inputText = 'Pls perform a Foo with name "GHJK".';
console.log('===HUMAN PROMPT=== (5)\n', inputText);
invokeWith = { messages: [new HumanMessage(inputText)] };
agentResult = await graph.invoke(invokeWith, graphConfig);

state = await graph.getState(graphConfig);
console.log('===STATE NEXT (6)===\n', state.next);
console.log('=LAST MSG=\n', agentResult.messages.at(-1).content);
console.log('=LAST TOOL CALLS=\n', agentResult.messages.at(-1).tool_calls);