index.ts

import { AIMessage, HumanMessage } from '@langchain/core/messages';
import { ChatGoogleGenerativeAI } from '@langchain/google-genai';
import { createReactAgent } from '@langchain/langgraph/prebuilt';
import { MultiServerMCPClient } from '@langchain/mcp-adapters';
// import { ChatOllama } from '@langchain/ollama';
import { stdin as input, stdout as output } from 'node:process';
import readlinePromises from 'node:readline/promises';
import { mcpServers } from './servers/mcpServers';
import { prompt } from './SystemPrompts/playwrightPrompt';
import { customTools } from './tools/customTools';

const exitCommands = ['exit', 'bye', 'stop'];

async function runChat() {
	const rl = readlinePromises.createInterface({ input, output });
	const client = new MultiServerMCPClient(mcpServers);

	const llm = new ChatGoogleGenerativeAI({ model: 'gemini-2.0-flash' });
	const clientTools = await client.getTools();
	const tools = [...customTools, ...clientTools];
	const llmWithTools = llm.bindTools(tools);
	const chatHistory = [prompt];
	const prebuiltAgent = createReactAgent({
		llm: llmWithTools,
		tools,
	});
	while (true) {
		const userInput = (await rl.question("You: ")).trim();
		if (!userInput) continue;
		if (exitCommands.includes(userInput.toLocaleLowerCase())) break;
		chatHistory.push(new HumanMessage(userInput));
		try {
			const result = await prebuiltAgent.invoke({
				messages: chatHistory,

			});

			const answer = result.messages?.at(-1)?.content;

			if (answer) {
				rl.write(`${answer}\n`);
				chatHistory.push(new AIMessage(answer.toString()));
			} else {
				console.log("Something went wrong, there was no agent content.");
				break;
			}
		} catch (err: any) {
			console.error("Agent error: ", err.message);
		}
	}
	rl.close();
	await client?.close();
	console.log("KthanxBai");
}

runChat();