Langfuse MCP

by hugoles

TypeScript MCP server exposing Langfuse Public API for querying traces, observations, sessions, scores, prompts, datasets, and metrics.

Monitoring
1stars
No ratings
UpdatedAug 9, 2026

InstallRepository Website

Install Langfuse MCP

Pick your client, then add it in one click or paste the config.

STDIONode.js

~/Library/Application Support/Claude/claude_desktop_config.json

claude_desktop_config.json

{
  "mcpServers": {
    "hugoles-langfuse-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "langfuse-mcp"
      ],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "YOUR_VALUE_HERE"
      }
    }
  }
}

Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.

Values are written into the snippet above so you can paste it as is. They never leave your browser.

We couldn’t confirm it starts correctly

We ran the install command but it didn't respond within our test window — this can mean a slow first-time install rather than a real problem.

npx -y langfuse-mcp

No response to initialize.

This is an experimental automated check and can have false negatives — missing environment variables, a slow cold install, etc. It doesn’t necessarily mean something’s wrong. Last checked 1mo ago.

Overview

Node.js

This MCP server wraps the Langfuse Public API, providing read-only access to various Langfuse resources such as traces, observations, sessions, scores, prompts, datasets, and metrics. It enables AI agents to query detailed telemetry and evaluation data during conversations without leaving the assistant interface. Use it when you want programmatic, conversational access to Langfuse monitoring and evaluation data.

Use cases

Query trace details including full observation trees
List recent traces filtered by error level or user
Summarize daily generation costs broken down by model
Fetch specific prompt versions or labels
Retrieve dataset items and evaluation run details

Key features

Read-only tools for traces, observations, sessions, and scores
Prompt management with version and label filtering
Dataset and dataset run listing and retrieval
Custom metrics queries and daily aggregated metrics
Model and project listing with cost and token attribution
Health check endpoint for credential validation

Tools27

What Langfuse MCP lets your agent do. Expand a tool for its parameters.

Self-reported~403 tokens of context

Security & health

What it can reach and how reliably it runs — from our own checks, not the maintainer’s claims.

ActiveLast checked 3d ago

Recent health check succeeded.

19/19 checks healthy over the last 80d

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 10d ago via OSV.dev · langfuse-mcp (npm)

Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

GitHub stars1Stargazers on the source repository.

npm downloads480Package downloads in the last 30 days.

Last commit4mo agoMost recent push to the default branch.

Install checkInconclusiveDidn't respond in our test window — often a slow first install.

Tools exposed27Callable tools this server registers over MCP.

Directory activity6 viewsConfig copies, upvotes, and views on AllMCPs.

From the project README

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 abc123 fail? Walk me through its observations."
"List the 5 most recent traces with level=ERROR for user alice@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.

Sessions

Tool	Description
`listSessions`	List sessions within a time range.
`getSession`	Fetch a session by id, including its traces.

Scores

Tool	Description
`listScores`	List scores with filters.
`getScore`	Fetch a single score by id.
`listScoreConfigs`	List score configurations (definitions, ranges, categories).
`getScoreConfig`	Fetch a score configuration by id.

Prompts

Tool	Description
`listPrompts`	List prompt definitions, optionally filtered by name, label, or tag.
`getPrompt`	Fetch a prompt by name, optionally pinned to a specific version or label.

Datasets

Tool	Description
`listDatasets`	List datasets configured in Langfuse.
`getDataset`	Fetch a dataset by name.
`listDatasetItems`	List items in a dataset (inputs, expected outputs, metadata).
`getDatasetItem`	Fetch a single dataset item by id.
`listDatasetRuns`	List evaluation runs for a dataset.
`getDatasetRun`	Fetch a specific dataset run by name.

Metrics, models & misc

Tool	Description
`getMetrics`	Run a custom metrics query (counts, latency, cost, token usage). Pass a JSON query string.
`getDailyMetrics`	Daily aggregated usage / cost / count metrics.
`listModels`	List models known to Langfuse (for cost / token attribution).
`getModel`	Fetch a model definition by id.
`listProjects`	List projects accessible to the current API key.
`listComments`	List comments attached to traces, observations, sessions, or prompts.
`getComment`	Fetch a single comment by id.
`getMedia`	Fetch metadata for a media attachment (image, audio, file).
`getHealth`	Ping the Langfuse public health endpoint — useful for credential validation.

Install

Zero install with npx:

Terminal

npx -y langfuse-mcp

Or install globally:

Terminal

npm i -g langfuse-mcp
langfuse-mcp --version

Configuration

The server reads three environment variables:

Variable	Required	Description
`LANGFUSE_PUBLIC_KEY`	yes	Project public key (`pk-lf-…`).
`LANGFUSE_SECRET_KEY`	yes	Project secret key (`sk-lf-…`).
`LANGFUSE_BASE_URL`	yes	e.g. `https://cloud.langfuse.com` (EU) or `https://us.cloud.langfuse.com` (US) or your self-hosted URL.
`LANGFUSE_ENV_FILE`	no	Optional path to a `.env` file to load instead of `./.env`.

Where do I get my keys? In the Langfuse UI: Settings → API Keys → Create new API keys. Keys are scoped to a single project and a single region (EU vs US are separate accounts — match your LANGFUSE_BASE_URL to the region you created the keys in).

If a .env file exists in the working directory it will be loaded automatically. See .env.example for a starter file.

Use with Claude Desktop

Edit claude_desktop_config.json:

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

config.json

{
  "mcpServers": {
    "langfuse": {
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  }
}

Restart Claude Desktop after editing. The MCP server icon should appear in the chat input.

Use with Claude Code

Project-level (./.mcp.json):

config.json

{
  "mcpServers": {
    "langfuse": {
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  }
}

User-level config lives at ~/.claude.json and uses the same shape.

Use with Cursor

Project-level: .cursor/mcp.json. User-level: ~/.cursor/mcp.json.

config.json

{
  "mcpServers": {
    "langfuse": {
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  }
}

Use with Cline (VS Code)

In VS Code settings (settings.json):

config.json

{
  "cline.mcpServers": {
    "langfuse": {
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  }
}

Use with Continue

In ~/.continue/config.json:

config.json

{
  "mcpServers": [
    {
      "name": "langfuse",
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  ]
}

Use with Windsurf

In Windsurf's MCP settings, add:

config.json

{
  "mcpServers": {
    "langfuse": {
      "command": "npx",
      "args": ["-y", "langfuse-mcp"],
      "env": {
        "LANGFUSE_PUBLIC_KEY": "pk-lf-…",
        "LANGFUSE_SECRET_KEY": "sk-lf-…",
        "LANGFUSE_BASE_URL": "https://cloud.langfuse.com"
      }
    }
  }
}

Use with any other MCP client

The server speaks MCP over stdio. Any MCP client can launch it as a subprocess:

bash

LANGFUSE_PUBLIC_KEY=pk-lf-… \
LANGFUSE_SECRET_KEY=sk-lf-… \
LANGFUSE_BASE_URL=https://cloud.langfuse.com \
npx -y langfuse-mcp

Try it

Once wired up, ask your assistant things like:

Read the full README View source on GitHub

Reviews

No reviews yet — be the first to share how it worked for you.

Frequently Asked Questions about Langfuse MCP

It requires a Langfuse project API key used as Basic Auth for the Langfuse Public API.

No, all exposed tools are read-only and only fetch data from Langfuse.

LANGFUSE_PUBLIC_KEY is required to authenticate requests to Langfuse.

Node.js version 20 or newer is required.

You can run it directly with 'npx -y langfuse-mcp' or install globally via npm.

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At a glance

Category: Monitoring
Transport: STDIO
Runtime: Node.js
Auth: API key
Pricing: Bring your own API key (usage-based cost)
License: MIT
Clients: Claude Desktop, Cursor, Windsurf, Cline / VS Code
Last updated: Aug 9, 2026

GitHub stars1

Last commit4mo ago

npm / month480

59Quality signal: Good · 59/100How this signal is calculated ▾

Server availabilityNot measured

Not scored for repo-hosted servers — we can't reach the running server, only its GitHub page. Hosted MCP endpoints are health-checked live.

Verified ownership10/20

Documentation & tools29/30

Adoption & activity4/15

Community engagement1/10

A guidance signal from public completeness & health data — not a user rating. New listings start lower and rise as they add docs, get verified, and grow adoption. Signals we can't observe for a listing are skipped, not counted against it.

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Install Langfuse MCP

Use cases

Key features

Supply-chain signal

Adoption & maintenance

From the project README

langfuse-mcp

Requirements

Tools

Traces & observations

Sessions

Scores

Prompts

Datasets

Metrics, models & misc

Install

Configuration

Use with Claude Desktop

Use with Claude Code

Use with Cursor

Use with Cline (VS Code)

Use with Continue

Use with Windsurf

Use with any other MCP client

Try it

Frequently Asked Questions about Langfuse MCP

What authentication does this server require?

Can I write or modify data using this MCP server?

What environment variables must be set to run this server?

Which Node.js version is required?

How do I install and run this MCP server?

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