langfuse-mcp
An MCP server that exposes the Langfuse REST API as tools, so Claude (or any MCP client) can query your traces, observations, sessions, scores, prompts, datasets, and metrics during a conversation.
Useful when you want to ask things like:
- "Why did trace
abc123fail? Walk me through its observations." - "List the 5 most recent traces with
level=ERRORfor useralice@x.com." - "Summarize today's generation cost broken down by model."
- "Show me the production version of prompt
customer-support-v2."
…without leaving your assistant.
Requirements
- Node.js 20 or newer (
node --version). - A Langfuse project with API keys (cloud.langfuse.com → Settings → API Keys on EU cloud, us.cloud.langfuse.com on US cloud, or your self-hosted instance).
Tools
All tools are read-only and call the Langfuse Public API over HTTPS using your project keys for Basic Auth.
Traces & observations
| Tool | Description |
|---|---|
listTraces |
List traces with filters. Returns summary metadata. |
getTrace |
Fetch a single trace by id including the full observation tree. |
listObservations |
List spans, generations, and events with filters. |
getObservation |
Fetch a single observation by id. |






