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Langfuse Mcp

@hugoles

About Langfuse Mcp

TypeScript MCP server for the Langfuse Public API with tools to query traces, observations, sessions, scores, prompts, datasets, and metrics from any MCP client.

Config

Add this server to your MCP-compatible client using the configuration below.

{
  "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"
      }
    }
  }
}

Tools

27

List Langfuse traces with filters. Returns summary metadata (use getTrace for the full observation tree).

Fetch a single trace by id including all nested observations.

List observations (spans, generations, events) with filters.

Fetch a single observation by id.

List sessions within a time range.

Fetch a session by id, including its traces.

List scores with filters.

Fetch a single score by id.

List score configurations (definitions for score names, ranges, and categories).

Fetch a single score configuration by id.

List prompt definitions tracked in Langfuse.

Fetch a prompt by name. Optionally pin to a specific version or label (e.g. 'production').

List datasets configured in Langfuse.

Fetch metadata for a dataset by its name.

List items in a dataset (inputs / expected outputs / metadata).

Fetch a single dataset item by id.

List runs (evaluation rounds) for a dataset.

Fetch a specific dataset run by name.

Run a metrics query (counts, latency, cost, token usage). Pass a JSON query string per the Langfuse metrics API.

Fetch daily aggregated usage / cost / count metrics for traces and observations.

List models known to Langfuse (for cost / token attribution).

Fetch a single model definition by id.

List projects accessible to the current API key (typically a single project).

List comments attached to traces, observations, sessions, or prompts.

Fetch a single comment by id.

Fetch metadata for a media attachment (image, audio, file) by id.

Pings the Langfuse public health endpoint. Useful to validate credentials and connectivity.

Overview

What is Langfuse Mcp?

A TypeScript MCP server that integrates with the Langfuse Public API, providing tools to query traces, observations, sessions, scores, prompts, datasets, and metrics from any MCP client.

How to use Langfuse Mcp?

Key features of Langfuse Mcp

  • TypeScript MCP server for the Langfuse Public API
  • Query traces, observations, and sessions
  • Query scores, prompts, and datasets
  • Query metrics
  • Accessible from any MCP client

Use cases of Langfuse Mcp

  • Retrieve Langfuse traces via MCP
  • Fetch observations and sessions
  • Access scores, prompts, and datasets
  • Obtain metrics from Langfuse

FAQ from Langfuse Mcp

What does Langfuse Mcp do?

It is a TypeScript MCP server for the Langfuse Public API, enabling queries of traces, observations, sessions, scores, prompts, datasets, and metrics.

What data can I query with Langfuse Mcp?

Traces, observations, sessions, scores, prompts, datasets, and metrics.

Frequently asked questions

What does Langfuse Mcp do?

It is a TypeScript MCP server for the Langfuse Public API, enabling queries of traces, observations, sessions, scores, prompts, datasets, and metrics.

What data can I query with Langfuse Mcp?

Traces, observations, sessions, scores, prompts, datasets, and metrics.

Comments

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