Agent skill · software engineering · jeremylongshore
langfuse-install-auth
Install and configure Langfuse SDK authentication for LLM observability.
Why this skill is useful
Provides specific installation and configuration commands for the Langfuse SDK that are not widely known.
What it needs
Requires node, python installed locally. Requires langfuse account access. About 3k tokens when loaded. Last updated 2026-08-07. 2,604 stars on the source repository.
What this skill does
Langfuse Install & Auth Overview Install the Langfuse SDK and configure authentication for LLM observability. Covers both the legacy langfuse package (v3) and the modern modular SDK (v4+/v5) built on OpenTelemetry. Prerequisites Node.js 18+ or Python 3.9+ Package manager (npm, pnpm, or pip) Langfuse account (cloud at https://cloud.langfuse.com or self-hosted) Public Key (pk-lf-...) and Secret Key (sk-lf-...) from project settings Instructions Step 1: Install SDK TypeScript/JavaScript (v4+ modular SDK -- recommended): TypeScript/JavaScript (v3 legacy -- single package): Python: Step 2: Get API Keys 1. Open Langfuse dashboard (https://cloud.langfuse.com or your self-hosted URL) 2. Go to Settings > API Keys 3. Click Create new API key pair 4. Copy both keys: Public Key: pk-lf-... (identifies your project) Secret Key: sk-lf-... (grants write access -- keep secret) 5. Note the host URL (cloud default: https://cloud.langfuse.com) Step 3: Configure Environment Variables Note: v4+ uses LANGFUSEBASEURL. Legacy v3 uses LANGFUSEHOST or LANGFUSEBASEURL. Step 4: Initialize and Verify (v4+ Modular SDK) Step 5: Initialize and Verify (v3 Legacy SDK) Step 6: Python Verification SDK Version Comparison Feature v3 (langfuse) v4+ (@langfuse/) --------- ----------------- --------------------- Package Single langfuse Modular: @langfuse/client, @langfuse/tracing, @langfuse/otel Base URL env var LANGFUSEHOST LANGFUSEBASEURL Tracing langfuse.trace() startActiveObservation() / observe() Client class Langfuse LangfuseClient OpenAI wrapper observeOpenAI() from langfuse observeOpenAI() from @langfuse/openai Foundation Custom OpenTelemetry Error Handling Error Cause Solution ------- ------- ---------- 401 Unauthorized Invalid or expired API key Re-check keys in Langfuse dashboard Settings > API Keys ECONNREFUSED Wrong host URL or server down Verify LANGFUSEBASEURL / LANGFUSEHOST Missing required configuration Env vars not loaded Ensure dotenv/config imported at entry point Module not found Packag …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills jeremylongshore/langfuse-install-auth--7c5389