n8n-mcp/docs/AI_AGENT_EXTRACTION_TEST.md

AI Agent Node Extraction Test Guide

This document describes how to test the MCP server's ability to extract and provide the AI Agent node source code from n8n.

Test Scenario

An MCP client (like an AI assistant) requests the source code for n8n's AI Agent node, and the MCP server successfully extracts and returns it.

Implementation Overview

1. New MCP Tools Added

• get_node_source_code: Extracts source code for any n8n node
• list_available_nodes: Lists all available n8n nodes

2. New Components

• NodeSourceExtractor (src/utils/node-source-extractor.ts): Handles file system access to extract node source code
• Resource endpoint: nodes://source/{nodeType} for accessing node code via resources

3. Test Infrastructure

• Docker setup (docker-compose.test.yml): Mounts n8n's node_modules for source access
• Test scripts: Multiple test approaches for different scenarios

Running the Tests

Option 1: Docker-based Test

# Build the project
npm run build

# Run the comprehensive test
./scripts/test-ai-agent-extraction.sh

This script will:

1. Build Docker containers
2. Start n8n and MCP server
3. Check for AI Agent node availability
4. Test source code extraction

Option 2: Standalone MCP Test

# Build the project
npm run build

# Ensure n8n is running (locally or in Docker)
docker-compose -f docker-compose.test.yml up -d n8n

# Run the MCP client test
node tests/test-mcp-extraction.js

Option 3: Manual Testing

1. Start the environment:

docker-compose -f docker-compose.test.yml up -d

2. Use any MCP client to connect and request:

{
  "method": "tools/call",
  "params": {
    "name": "get_node_source_code",
    "arguments": {
      "nodeType": "@n8n/n8n-nodes-langchain.Agent",
      "includeCredentials": true
    }
  }
}

Expected Results

Successful Extraction Response

{
  "nodeType": "@n8n/n8n-nodes-langchain.Agent",
  "sourceCode": "/* AI Agent node JavaScript code */",
  "location": "/usr/local/lib/node_modules/n8n/node_modules/@n8n/n8n-nodes-langchain/dist/nodes/agents/Agent/Agent.node.js",
  "credentialCode": "/* Optional credential code */",
  "packageInfo": {
    "name": "@n8n/n8n-nodes-langchain",
    "version": "1.x.x",
    "description": "LangChain nodes for n8n"
  }
}

How It Works

1. MCP Client Request: Client calls get_node_source_code tool with node type
2. Server Processing: MCP server receives request and invokes NodeSourceExtractor
3. File System Search: Extractor searches known n8n paths for the node file
4. Source Extraction: Reads the JavaScript source code and optional credential files
5. Response Formation: Returns structured data with source code and metadata

Troubleshooting

Node Not Found

If the AI Agent node is not found:

1. Check if langchain nodes are installed:

docker exec n8n-test ls /usr/local/lib/node_modules/n8n/node_modules/@n8n/

2. Install langchain nodes:

docker exec n8n-test npm install -g @n8n/n8n-nodes-langchain

Permission Issues

Ensure the MCP container has read access to n8n's node_modules:

volumes:
  - n8n_modules:/usr/local/lib/node_modules/n8n/node_modules:ro

Alternative Node Types

You can test with other built-in nodes:

• n8n-nodes-base.HttpRequest
• n8n-nodes-base.Code
• n8n-nodes-base.If

Success Criteria

The test is successful when:

1. ✅ MCP server starts and accepts connections
2. ✅ Client can discover the get_node_source_code tool
3. ✅ Server locates the AI Agent node in the file system
4. ✅ Complete source code is extracted and returned
5. ✅ Response includes metadata (location, package info)

Security Considerations

• Source code extraction is read-only
• Access is limited to n8n's node_modules directory
• Authentication token required for MCP server access
• No modification of files is possible

Next Steps

After successful testing:

1. Deploy to production environment
2. Configure proper authentication
3. Set up monitoring for extraction requests
4. Document available node types for users