Web search in LangChain and LangGraph with x402serps

from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent

client = MultiServerMCPClient({
    "x402serps": {
        "transport": "streamable_http",
        "url": "https://x402serps.com/api/mcp",
        "headers": {"X-Trial": "1"},  # or {"Authorization": "Bearer xs_YOUR_KEY"}
    }
})
tools = await client.get_tools()
agent = create_react_agent("openai:gpt-4.1", tools)
res = await agent.ainvoke({"messages": "Search the web for x402 protocol news"})

Install the adapters with pip install langchain-mcp-adapters langgraph.

import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createReactAgent } from "@langchain/langgraph/prebuilt";

const client = new MultiServerMCPClient({
  x402serps: {
    transport: "http",
    url: "https://x402serps.com/api/mcp",
    headers: { Authorization: `Bearer ${process.env.X402SERPS_KEY}` },
  },
});
const tools = await client.getTools();
const agent = createReactAgent({ llm, tools });

Pay per call with x402 instead: tool calls without a trial header or key return the x402 payment requirements, which an x402-aware client can pay in USDC on Base or Solana. Search is $0.004 a call. Buy a credit key on the pricing page.