🦆 MCP Rubber Duck

An MCP (Model Context Protocol) server that acts as a bridge to query multiple OpenAI-compatible LLMs. Just like rubber duck debugging, explain your problems to various AI "ducks" and get different perspectives!

     __
   <(o )___
    ( ._> /
     `---'  Quack! Ready to debug!

Features

• 🔌 Universal OpenAI Compatibility: Works with any OpenAI-compatible API endpoint
• 🦆 Multiple Ducks: Configure and query multiple LLM providers simultaneously
• 💬 Conversation Management: Maintain context across multiple messages
• 🏛️ Duck Council: Get responses from all your configured LLMs at once
• 💾 Response Caching: Avoid duplicate API calls with intelligent caching
• 🔄 Automatic Failover: Falls back to other providers if primary fails
• 📊 Health Monitoring: Real-time health checks for all providers
• 🎨 Fun Duck Theme: Rubber duck debugging with personality!

Supported Providers

Any provider with an OpenAI-compatible API endpoint, including:

• OpenAI (GPT-4, GPT-3.5)
• Google Gemini (Gemini 2.5 Flash, Gemini 2.0 Flash)
• Anthropic (via OpenAI-compatible endpoints)
• Groq (Llama, Mixtral, Gemma)
• Together AI (Llama, Mixtral, and more)
• Perplexity (Online models with web search)
• Anyscale (Open source models)
• Azure OpenAI (Microsoft-hosted OpenAI)
• Ollama (Local models)
• LM Studio (Local models)
• Custom (Any OpenAI-compatible endpoint)

Quick Start

For Claude Desktop Users

👉 Complete Claude Desktop setup instructions below in Claude Desktop Configuration

Installation

Prerequisites

• Node.js 20 or higher
• npm or yarn
• At least one API key for a supported provider

Install from Source

# Clone the repository
git clone https://github.com/yourusername/mcp-rubber-duck.git
cd mcp-rubber-duck

# Install dependencies
npm install

# Build the project
npm run build

# Run the server
npm start

Configuration

Method 1: Environment Variables

Create a .env file in the project root:

# OpenAI
OPENAI_API_KEY=sk-...
OPENAI_DEFAULT_MODEL=gpt-4o-mini  # Optional: defaults to gpt-4o-mini

# Google Gemini
GEMINI_API_KEY=...
GEMINI_DEFAULT_MODEL=gemini-2.5-flash  # Optional: defaults to gemini-2.5-flash

# Groq
GROQ_API_KEY=gsk_...
GROQ_DEFAULT_MODEL=llama-3.3-70b-versatile  # Optional: defaults to llama-3.3-70b-versatile

# Ollama (Local)
OLLAMA_BASE_URL=http://localhost:11434/v1  # Optional
OLLAMA_DEFAULT_MODEL=llama3.2  # Optional: defaults to llama3.2

# Together AI
TOGETHER_API_KEY=...

# Custom Provider
CUSTOM_API_KEY=...
CUSTOM_BASE_URL=https://api.example.com/v1
CUSTOM_DEFAULT_MODEL=custom-model  # Optional: defaults to custom-model

# Global Settings
DEFAULT_PROVIDER=openai
DEFAULT_TEMPERATURE=0.7
LOG_LEVEL=info

# Optional: Custom Duck Nicknames (Have fun with these!)
OPENAI_NICKNAME="DUCK-4"              # Optional: defaults to "GPT Duck"
GEMINI_NICKNAME="Duckmini"            # Optional: defaults to "Gemini Duck"
GROQ_NICKNAME="Quackers"              # Optional: defaults to "Groq Duck"
OLLAMA_NICKNAME="Local Quacker"       # Optional: defaults to "Local Duck"
CUSTOM_NICKNAME="My Special Duck"     # Optional: defaults to "Custom Duck"

Note: Duck nicknames are completely optional! If you don't set them, you'll get the charming defaults (GPT Duck, Gemini Duck, etc.). If you use a config.json file, those nicknames take priority over environment variables.

Method 2: Configuration File

Create a config/config.json file based on the example:

cp config/config.example.json config/config.json
# Edit config/config.json with your API keys and preferences

Claude Desktop Configuration

This is the most common setup method for using MCP Rubber Duck with Claude Desktop.

Step 1: Build the Project

First, ensure the project is built:

# Clone the repository
git clone https://github.com/yourusername/mcp-rubber-duck.git
cd mcp-rubber-duck

# Install dependencies and build
npm install
npm run build

Step 2: Configure Claude Desktop

Edit your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Add the MCP server configuration:

{
  "mcpServers": {
    "rubber-duck": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-rubber-duck/dist/index.js"],
      "env": {
        "OPENAI_API_KEY": "your-openai-api-key-here",
        "OPENAI_DEFAULT_MODEL": "gpt-4o-mini",
        "GEMINI_API_KEY": "your-gemini-api-key-here", 
        "GEMINI_DEFAULT_MODEL": "gemini-2.5-flash",
        "DEFAULT_PROVIDER": "openai",
        "LOG_LEVEL": "info"
      }
    }
  }
}

Important: Replace the placeholder API keys with your actual keys:

• your-openai-api-key-here → Your OpenAI API key (starts with sk-)
• your-gemini-api-key-here → Your Gemini API key from Google AI Studio

Step 3: Restart Claude Desktop

1. Completely quit Claude Desktop (⌘+Q on Mac)
2. Launch Claude Desktop again
3. The MCP server should connect automatically

Step 4: Test the Integration

Once restarted, test these commands in Claude:

Check Duck Health

Use the list_ducks tool with check_health: true

Should show:

• ✅ GPT Duck (openai) - Healthy
• ✅ Gemini Duck (gemini) - Healthy

List Available Models

Use the list_models tool

Ask a Specific Duck

Use the ask_duck tool with prompt: "What is rubber duck debugging?", provider: "openai"

Compare Multiple Ducks

Use the compare_ducks tool with prompt: "Explain async/await in JavaScript"

Test Specific Models

Use the ask_duck tool with prompt: "Hello", provider: "openai", model: "gpt-4"

Troubleshooting Claude Desktop Setup

If Tools Don't Appear

1. Check API Keys: Ensure your API keys are correctly entered without typos
2. Verify Build: Run ls -la dist/index.js to confirm the project built successfully
3. Check Logs: Look for errors in Claude Desktop's developer console
4. Restart: Fully quit and restart Claude Desktop after config changes

Connection Issues

1. Config File Path: Double-check you're editing the correct config file path
2. JSON Syntax: Validate your JSON syntax (no trailing commas, proper quotes)
3. Absolute Paths: Ensure you're using the full absolute path to dist/index.js
4. File Permissions: Verify Claude Desktop can read the dist directory

Health Check Failures

If ducks show as unhealthy:

1. API Keys: Verify keys are valid and have sufficient credits/quota
2. Network: Check internet connection and firewall settings
3. Rate Limits: Some providers have strict rate limits for new accounts

Available Tools

🦆 ask_duck

Ask a single question to a specific LLM provider.

{
  "prompt": "What is rubber duck debugging?",
  "provider": "openai",  // Optional, uses default if not specified
  "temperature": 0.7     // Optional
}

💬 chat_with_duck

Have a conversation with context maintained across messages.

{
  "conversation_id": "debug-session-1",
  "message": "Can you help me debug this code?",
  "provider": "groq"  // Optional, can switch providers mid-conversation
}

📋 list_ducks

List all configured providers and their health status.

{
  "check_health": true  // Optional, performs fresh health check
}

📊 list_models

List available models for LLM providers.

{
  "provider": "openai",     // Optional, lists all if not specified
  "fetch_latest": false     // Optional, fetch latest from API vs cached
}

🔍 compare_ducks

Ask the same question to multiple providers simultaneously.

{
  "prompt": "What's the best programming language?",
  "providers": ["openai", "groq", "ollama"]  // Optional, uses all if not specified
}

🏛️ duck_council

Get responses from all configured ducks - like a panel discussion!

{
  "prompt": "How should I architect a microservices application?"
}

Usage Examples

Basic Query

// Ask the default duck
await ask_duck({ 
  prompt: "Explain async/await in JavaScript" 
});

Conversation

// Start a conversation
await chat_with_duck({
  conversation_id: "learning-session",
  message: "What is TypeScript?"
});

// Continue the conversation
await chat_with_duck({
  conversation_id: "learning-session", 
  message: "How does it differ from JavaScript?"
});

Compare Responses

// Get different perspectives
await compare_ducks({
  prompt: "What's the best way to handle errors in Node.js?",
  providers: ["openai", "groq", "ollama"]
});

Duck Council

// Convene the council for important decisions
await duck_council({
  prompt: "Should I use REST or GraphQL for my API?"
});

Provider-Specific Setup

Ollama (Local)

# Install Ollama
curl -fsSL https://ollama.ai/install.sh | sh

# Pull a model
ollama pull llama3.2

# Ollama automatically provides OpenAI-compatible endpoint at localhost:11434/v1

LM Studio (Local)

1. Download LM Studio from https://lmstudio.ai/
2. Load a model in LM Studio
3. Start the local server (provides OpenAI-compatible endpoint at localhost:1234/v1)

Google Gemini

1. Get API key from Google AI Studio
2. Add to environment: GEMINI_API_KEY=...
3. Uses OpenAI-compatible endpoint (beta)

Groq

1. Get API key from https://console.groq.com/keys
2. Add to environment: GROQ_API_KEY=gsk_...

Together AI

1. Get API key from https://api.together.xyz/
2. Add to environment: TOGETHER_API_KEY=...

Verifying OpenAI Compatibility

To check if a provider is OpenAI-compatible:

1. Look for /v1/chat/completions endpoint in their API docs
2. Check if they support the OpenAI SDK
3. Test with curl:

curl -X POST "https://api.provider.com/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "model-name",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Development

Run in Development Mode

npm run dev

Run Tests

npm test

Lint Code

npm run lint

Type Checking

npm run typecheck

Docker Support

Build Docker Image

docker build -t mcp-rubber-duck .

Run with Docker

docker run -it \
  -e OPENAI_API_KEY=sk-... \
  -e GROQ_API_KEY=gsk_... \
  mcp-rubber-duck

Architecture

mcp-rubber-duck/
├── src/
│   ├── server.ts           # MCP server implementation
│   ├── config/             # Configuration management
│   ├── providers/          # OpenAI client wrapper
│   ├── tools/              # MCP tool implementations
│   ├── services/           # Health, cache, conversations
│   └── utils/              # Logging, ASCII art
├── config/                 # Configuration examples
└── tests/                  # Test suites

Troubleshooting

Provider Not Working

1. Check API key is correctly set
2. Verify endpoint URL is correct
3. Run health check: list_ducks({ check_health: true })
4. Check logs for detailed error messages

Connection Issues

• For local providers (Ollama, LM Studio), ensure they're running
• Check firewall settings for local endpoints
• Verify network connectivity to cloud providers

Rate Limiting

• Enable caching to reduce API calls
• Configure failover to alternate providers
• Adjust max_retries and timeout settings

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Submit a pull request

License

MIT License - see LICENSE file for details

Acknowledgments

• Inspired by the rubber duck debugging method
• Built on the Model Context Protocol (MCP)
• Uses OpenAI SDK for universal compatibility

Support

• Report issues: https://github.com/yourusername/mcp-rubber-duck/issues
• Documentation: https://github.com/yourusername/mcp-rubber-duck/wiki
• Discussions: https://github.com/yourusername/mcp-rubber-duck/discussions

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🦆 Happy Debugging with your AI Duck Panel! 🦆