Langfuse Core Workflow A: Tracing LLM Calls

Overview

End-to-end tracing of LLM calls, chains, and agents. Covers the OpenAI drop-in wrapper, manual tracing with startActiveObservation, RAG pipeline instrumentation, streaming response tracking, and LangChain integration.

Prerequisites

• Completed langfuse-install-auth setup
• OpenAI SDK installed (npm install openai)
• For v4+: @langfuse/openai, @langfuse/tracing, @langfuse/otel, @opentelemetry/sdk-node

Instructions

Step 1: OpenAI Drop-In Wrapper (Zero-Code Tracing)

import OpenAI from "openai";
import { observeOpenAI } from "@langfuse/openai";

// Wrap the OpenAI client -- all calls are now traced automatically
const openai = observeOpenAI(new OpenAI());