@elad12390/mcp-server-langfuse

A tool that lets AI assistants (like Claude or Cursor) manage your prompt library stored in Langfuse.

What are prompts? Prompts are the instructions you give to AI models. Instead of writing them directly in your code, you can store them in Langfuse and manage them like documents - with versions, drafts, and the ability to update them without changing your code.

npx -y @elad12390/mcp-server-langfuse  # requires LANGFUSE_* env vars

What Can You Do?

| Tool | What it does | | ---- | ------------ | | get-prompts | List all your saved prompts | | get-prompt | Get the exact content of a prompt (with all {{variables}} intact) | | edit-prompt | Create or update a prompt. Set publish=true to make it live immediately | | publish-prompt | Mark a draft version as "production" (live) | | list-prompt-versions | See all versions of a prompt | | search-prompts | Find prompts by name, label, or tag | | validate-prompt | Check a prompt for syntax errors before saving | | diff-prompt | Preview what will change BEFORE you edit (compare new content vs current production) | | compare-versions | See differences between any two versions | | rollback-prompt | Go back to an older version if something breaks |

Quick Start

# 1. Set your Langfuse credentials
export LANGFUSE_PUBLIC_KEY="pk-..."
export LANGFUSE_SECRET_KEY="sk-..."
export LANGFUSE_BASEURL="https://cloud.langfuse.com"   # optional

# 2. Run it
npx -y @solaraai/mcp-server-langfuse

Example: Add to Cursor

Add this to your MCP config:

{
  "mcpServers": {
    "langfuse-prompts": {
      "command": "npx",
      "args": ["-y", "@solaraai/mcp-server-langfuse"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-...",
        "LANGFUSE_SECRET_KEY": "sk-...",
        "LANGFUSE_BASEURL": "https://cloud.langfuse.com"
      },
      "transportType": "stdio"
    }
  }
}

Common Workflows

1. View a prompt exactly as stored

get-prompt name="support/greeting"

Returns the raw content with all {{variables}} intact - perfect for reviewing and editing.

2. Edit and publish in one step

edit-prompt name="support/greeting" prompt="..." publish=true

Creates a new version AND marks it as production immediately.

3. Safe editing workflow (recommended)

# First, see what will change
diff-prompt name="support/greeting" newPrompt="..."

# If it looks good, save it
edit-prompt name="support/greeting" prompt="..." publish=true

4. Something went wrong? Roll back

# See what versions exist
list-prompt-versions name="support/greeting"

# Compare current vs old version
compare-versions name="support/greeting" version1=3 version2=2

# Roll back to version 2
rollback-prompt name="support/greeting" targetVersion=2

Development

git clone https://github.com/solaraai/mcp-server-langfuse
cd mcp-server-langfuse
npm install
npm run build

# Run locally
LANGFUSE_PUBLIC_KEY=... node ./build/index.js

Notes

• get-prompt returns raw content with {{variables}} - it does NOT substitute values
• Every edit creates a new version - you never lose previous work
• Use diff-prompt before editing to review changes
• Only prompts labeled "production" show up in get-prompts (use search-prompts to find drafts)

Questions? Open an issue!