MCP Server User Guide

Prompt Optimizer supports the Model Context Protocol (MCP), enabling integration with AI applications that support MCP such as Claude Desktop.

🎯 Features

optimize-user-prompt: Optimize user prompts to improve LLM performance
optimize-system-prompt: Optimize system prompts to improve LLM performance
iterate-prompt: Iteratively improve mature prompts based on specific requirements

🚀 Quick Start

Docker Deployment (Recommended)

Docker is the simplest deployment method, with both Web interface and MCP server starting together:

# Basic deployment
docker run -d -p 8081:80 \
  -e VITE_OPENAI_API_KEY=your-openai-key \
  -e MCP_DEFAULT_MODEL_PROVIDER=openai \
  --name prompt-optimizer \
  linshen/prompt-optimizer

# Access URLs
# Web Interface: http://localhost:8081
# MCP Server: http://localhost:8081/mcp

Developer Local Deployment

Note: This method is only for developers for development and debugging. Regular users should use Docker deployment.

# 1. Clone the project
git clone https://github.com/your-repo/prompt-optimizer.git
cd prompt-optimizer

# 2. Install dependencies
pnpm install

# 3. Configure environment variables (copy and edit .env.local)
cp env.local.example .env.local

# 4. Start MCP server
pnpm mcp:dev

The server will start at http://localhost:3000/mcp. Developers can refer to the Developer Documentation for more development-related information.

⚙️ Environment Variable Configuration

API Key Configuration

At least one API key must be configured:

# Choose one or more API keys
VITE_OPENAI_API_KEY=your-openai-key
VITE_GEMINI_API_KEY=your-gemini-key
VITE_DEEPSEEK_API_KEY=your-deepseek-key
VITE_GROK_API_KEY=your-xai-key
VITE_SILICONFLOW_API_KEY=your-siliconflow-key
VITE_ZHIPU_API_KEY=your-zhipu-key

# Custom API (e.g., Ollama)
VITE_CUSTOM_API_KEY=your-custom-key
VITE_CUSTOM_API_BASE_URL=http://localhost:11434/v1
VITE_CUSTOM_API_MODEL=qwen2.5:0.5b

MCP Server Configuration

# Preferred model provider (when multiple API keys are configured)
# Options: openai, gemini, anthropic, deepseek, grok, siliconflow, zhipu, dashscope, openrouter, modelscope, custom
MCP_DEFAULT_MODEL_PROVIDER=openai

# Log level (optional, default: debug)
# Options: debug, info, warn, error
MCP_LOG_LEVEL=info

# HTTP port (optional, default: 3000, not needed for Docker deployment)
MCP_HTTP_PORT=3000

# Default language (optional, default: zh)
# Options: zh, en
MCP_DEFAULT_LANGUAGE=zh

🔗 Client Connections

Claude Desktop Integration

1. Find Configuration Directory

Windows: %APPDATA%\Claude\services
macOS: ~/Library/Application Support/Claude/services
Linux: ~/.config/Claude/services

2. Edit Configuration File

Create or edit the services.json file:

{
  "services": [
    {
      "name": "Prompt Optimizer",
      "url": "http://localhost:8081/mcp"
    }
  ]
}

Note: If you are using developer local deployment (port 3000), please change the URL to http://localhost:3000/mcp.

Other MCP Clients

The MCP server supports the standard MCP protocol and can be used by any compatible client:

Connection URLs:
- Docker deployment: http://localhost:8081/mcp
- Local deployment: http://localhost:3000/mcp
Protocol: HTTP Streamable
Transport: HTTP or stdio

🧪 Testing and Validation

Using MCP Inspector

MCP Inspector is the official testing tool:

# 1. Start MCP server
pnpm mcp:dev

# 2. Start Inspector in another terminal
npx @modelcontextprotocol/inspector

In the Inspector Web UI:

Select transport method: Streamable HTTP
Server URL: http://localhost:3000/mcp
Click "Connect" to connect to the server
Test available tools

🔧 Troubleshooting

Common Issues

1. Server Startup Failure

Error: Error: listen EADDRINUSE: address already in use Solution: Port is occupied, change port or stop the occupying process

# Check port usage
netstat -ano | findstr :3000

# Change port
MCP_HTTP_PORT=3001 pnpm mcp:dev

2. Invalid API Key

Error: No enabled models found Solution: Check API key configuration

# Ensure at least one valid API key is configured
echo $VITE_OPENAI_API_KEY

3. Model Provider Mismatch

Error: Using wrong model Solution: Check MCP_DEFAULT_MODEL_PROVIDER configuration

# Ensure provider name is correct
MCP_DEFAULT_MODEL_PROVIDER=openai  # not OpenAI

4. Docker Deployment 401 Authentication Error

Issue: After enabling ACCESS_PASSWORD in Docker deployment, MCP Inspector connection fails with 401 error

Cause: When password protection is enabled in Docker deployment, Nginx enables Basic authentication for all routes, including the /mcp route

Solutions:

Fixed (v1.4.0+): The /mcp route is now configured to bypass Basic authentication
Workarounds for older versions:
1. Don't set the ACCESS_PASSWORD environment variable
2. Use network isolation (e.g., internal network only)
3. Expose port 3000 directly: docker run -p 3000:3000 ...

Technical Details:

The MCP protocol itself doesn't support HTTP Basic authentication
The new version adds auth_basic off; for the /mcp route in docker/nginx.conf
Web application access remains password-protected

5. Claude Desktop Connection Failure

Solution Steps:

Confirm MCP server is running
Check if URL is correct
Confirm firewall settings
Check Claude Desktop logs

Debug Logging

Enable verbose logging:

# Development environment
MCP_LOG_LEVEL=debug pnpm mcp:dev

# Docker environment
docker run -e MCP_LOG_LEVEL=debug ...

📚 More Resources

🆘 Getting Help

If you encounter issues:

Check the troubleshooting section in this document
Check project Issues
Submit a new Issue describing the problem
Contact the development team

Source: docs/user/mcp-server_en.md