@mcplex-js/adapter-langgraph

LangGraph adapter for MCPlex with widget support.

Installation

npm install @mcplex-js/adapter-langgraph

Usage

import { generateWidget } from '@mcplex-js/adapter-langgraph';
import { initChatModel } from 'langchain/chat_models/universal';
import { MultiServerMCPClient } from '@langchain/mcp-adapters';

// Set up your LLM and tools
const llm = await initChatModel('gpt-4o');
const client = new MultiServerMCPClient({
  mcpServers: {
    ui: {
      url: 'http://localhost:3000/mcp',
      transport: 'http',
    },
  },
});
const tools = await client.getTools();

// Generate a widget response
const response = await generateWidget({
  state: { messages: [{ role: 'user', content: 'Show me a Pokemon card' }] },
  tools,
  llm
});

console.log('Response:', response.text);
console.log('Widget HTML:', response.widget);

API

generateWidget(options)

Generates a widget response using LangGraph agent with provided tools and LLM.

Parameters

• options.state (Object): Object containing langgraph messages and other state properties
• options.tools (Array): Array of LangChain tools
• options.llm (BaseChatModel): LangChain chat model instance

Returns

Promise resolving to an object with:

• widget: The HTML widget content (if available)
• text: Text response from the agent

License

ISC