langfuse-observability

name	langfuse-observability
description	Set up comprehensive observability for Langfuse with metrics, dashboards, and alerts. Use when implementing monitoring for LLM operations, setting up dashboards, or configuring alerting for Langfuse integration health. Trigger with phrases like "langfuse monitoring", "langfuse metrics", "langfuse observability", "monitor langfuse", "langfuse alerts", "langfuse dashboard".
allowed-tools	Read, Write, Edit
version	1.12.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","langfuse","monitoring","observability","llm"]
compatibility	Designed for Claude Code

Langfuse Observability

Overview

Set up monitoring for your Langfuse integration: Prometheus metrics for trace/generation throughput, Grafana dashboards, alert rules, and integration with Langfuse's built-in analytics dashboards and Metrics API.

Prerequisites

• Langfuse SDK integrated and producing traces
• For custom metrics: Prometheus + Grafana (or compatible stack)
• For Langfuse analytics: access to the Langfuse UI dashboard

Instructions

Step 1: Langfuse Built-In Dashboards

Langfuse provides pre-built dashboards in the UI at https://cloud.langfuse.com (or your self-hosted URL):

• Overview: Total traces, generations, scores, and errors
• Cost Dashboard: Token usage and costs over time, broken down by model, user, session
• Latency Dashboard: Response times across models and user segments
• Custom Dashboards: Build your own with the query engine (multi-level aggregations, filters by user/model/tag)

Accessing via Metrics API:

import { LangfuseClient } from "@langfuse/client";

const langfuse = new LangfuseClient();

// Fetch aggregated metrics programmatically
const traces = await langfuse.api.traces.list({
  fromTimestamp: new Date(Date.now() - 3600000).toISOString(), // Last hour
  limit: 100,
});

console.log(`Traces in last hour: ${traces.data.length}`);

// Get observations with cost data
 observations =  langfuse...({
  : ,
  :  (.() - ).(),
  : ,
});

 totalCost = observations..(
   sum + (obs. || ), 
);
.();