LangGraph Gateway Example

A LangGraph JavaScript agent with Lambda-backed tools exposed via an AgentCore Gateway using MCP protocol.

Features

• Gateway Tools: Lambda functions exposed as agent tools via MCP
• SigV4 Authentication: Secure AWS IAM authentication for gateway access
• Tool Discovery: Automatic tool discovery from gateway endpoint
• LangGraph JS: StateGraph with ToolNode and conditional routing

How It Works

1. Lambda function (calculatorFunction) is deployed as a standard AWS Lambda
2. The Serverless Framework creates a Gateway with the tool schema
3. The agent discovers tools at runtime via BEDROCK_AGENTCORE_GATEWAY_URL
4. MCP protocol is used to invoke tools through the gateway

Quick Start

Deploy

npm install
sls deploy

Test

RUNTIME_ARN=<your-runtime-arn> node test-invoke.js

Remove

sls remove

Related Examples

• langgraph-multi-gateway - Multiple gateways with different auth
• ../python/langgraph-gateway - Python version