Langfuse MCP Server Langfuse

🚀 Language Fusion Prompt Management MCP Server

A Model Context Protocol (MCP) server implemented for Langfuse Prompt Management. This server allows you to access and manage your Langfuse prompts via the Model Context Protocol.

🚀 Quick Start

Demo

A quick demonstration of Langfuse Prompts MCP in Claude Desktop (with voice explanation, please unmute): Video Link

✨ Features

MCP Prompts

This server implements the MCP Prompt Specification for prompt discovery and retrieval.

• prompts/list: List all available prompts

  • Optional cursor-based pagination
  • Return prompt names and their required parameters. Limitation: All parameters are assumed to be optional and do not include descriptions because variables in Langfuse are not explicitly specified.
  • Return the next cursor if there are more pages of prompts.

• prompts/get: Get a specific prompt

  • Convert Langfuse prompts (text and chat) to MCP prompt objects.
  • Compile the prompt using the provided variables.

Tools

To improve compatibility with other MCP clients that do not support prompt functions, this server also exports tools to simulate prompt functions.

• get-prompts: List available prompts

  • Optional cursor parameter for pagination
  • Return a list of prompts and their parameters

• get-prompt: Retrieve and compile a specific prompt

  • Required name parameter: The name of the prompt to retrieve
  • Optional arguments parameter: A JSON object containing prompt variables

📦 Installation

npm install

# Build the current file
npm run build

# Test with the MCP inspector
npx @modelcontextprotocol/inspector node ./build/index.js

💻 Usage Examples

Basic Usage

Step 1: Build

npm install
npm run build

Step 2: Add the server to your MCP service:

Configuration in Claude Desktop

Edit the claude_desktop_config.json file to configure Claude for Desktop:

{
  "mcpServers": {
    "langfuse": {
      "command": "node",
      "args": ["<absolute-path>/build/index.js"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "your-public-key",
        "LANGFUSE_SECRET_KEY": "your-secret-key",
        "LANGFUSE_BASEURL": "https://cloud.langfuse.com"
      }
    }
  }
}

Make sure to replace the environment variables with your actual Langfuse API keys. At this point, the server will be available in Claude Desktop.

Addition in Cursor

Add a new server in Cursor:

• Name: Langfuse Prompts
• Type: Command
• Command:

LANGFUSE_PUBLIC_KEY="your-public-key" LANGFUSE_SECRET_KEY="your-secret-key" LANGFUSE_BASEURL="https://cloud.langfuse.com" node absolute-path/build/index.js

🔧 Technical Details

This MCP server currently has some limitations:

• Only return prompts with the production tag in Langfuse.
• All parameters are assumed to be optional and do not include descriptions because variables in Langfuse are not explicitly specified.
• List operations need to fetch each prompt in the background to extract parameters, which is feasible but inefficient.

🤝 Contribution

Contributions are welcome! If you have any suggestions or feedback on the project, please contact us via issues or pull requests (Repository).