Launch Week 5 · Day 1: Experiments in CI/CD →
Workshop
WorkshopOverview

Langfuse Workshop — the AI engineering loop, end to end

Workshop source

Workshop material is maintained in the public langfuse/langfuse-workshop repository. Use the repository for the runnable app, checkpoint branches, and local setup.

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Introduction

This is a step-by-step Langfuse workshop built on a small sample application — the Dad IT Support Agent. Working through it takes you through every Langfuse module along the AI engineering loop: tracing, prompt management, monitoring, datasets, experiments, and evaluation.

The AI Engineering Loop

The sample app is a small web chat where Dad himself opens the chat to get iPhone help. The agent is named Specs and answers with step-by-step instructions. Under the hood it's a normal OpenAI tool-calling loop with two tools.

The Dad IT Support Agent sample app — Specs greeting Dad, suggestion chips, and the iPhone side panel.

Should I work through this?

If you can answer "yes" to any of these, yes:

  • I want to log my first trace from a real LLM app and understand what I'm looking at.
  • I want prompt management my whole team can edit — versioned and linked to traces.
  • I want to know what's happening in production without reading every trace by hand.
  • I want datasets, experiments, and evaluations wired up so every change ships with evidence.
  • I want a complete reference implementation in TypeScript I can copy patterns from.

The workshop is small enough to finish in a sitting and every module is independent — if you only care about one chapter, jump straight there.

How does it work?

This workshop lives in a GitHub repository. main contains the complete reference app and the current workshop docs. Use it to inspect the finished implementation or compare your work against the end state.

The exercises themselves start from checkpoint tags. Each learner chapter tells you which checkpoint to check out before making changes. The walkthrough is split into nine modules, each with a paired guide:

  • Learner path (you, if you're doing the workshop) — docs/learner/. Each chapter is the build/configure guide: what to check out, what to change, what to do in the Langfuse UI.
  • Instructor notes (if you're running the workshop for others) — docs/instructor/. Same chapters with extra narration, demo suggestions, teaching points.

Every workshop step has a git checkpoint named for the lesson it kicks off. checkpoint/00-setup and checkpoint/01-base-app are intentionally equivalent: both are the untraced base app before any Langfuse instrumentation. Setup uses that state to validate local credentials, install, and ports; Base App uses the same state for orientation. Later checkpoints then put you in the right starting state for each build chapter without losing the complete reference on main.

Modules

StepBranch (git checkout …)What you'll learn
00 Setupcheckpoint/00-setup (same state as 01-base-app)Keys, install, run the app.
01 Base Appcheckpoint/01-base-appOne-minute tour of the running app. Nothing to build.
02 Tracingcheckpoint/02-tracingLog every step the agent takes — generations, agent root, tool spans.
03 Prompt Managementcheckpoint/03-prompt-managementMove the system prompt into Langfuse so non-engineers can iterate.
04 Monitoringcheckpoint/04-monitoringCatch interesting production events (out-of-scope, disagreement).
05 Datasetcheckpoint/05-datasetTurn product scope into a starter dataset.
06 Experimentscheckpoint/06-experimentsRun the agent against the dataset, score every item.
07 Evaluationcheckpoint/07-evaluationChange one thing, rerun the dataset, compare runs side by side.
08 Wrap-upcheckpoint/08-wrap-upWhat to take home, how to apply this to your own app.

Each checkpoint/0X-… tag is the starting state of that lesson. checkpoint/00-setup is intentionally equivalent to checkpoint/01-base-app; both are the base app learners use before making tracing changes. See docs/checkpoints.md for the convention.

Instructor notes for the same modules live in docs/instructor/.

Where to go next

  • Walk the modules in order starting from docs/learner/00-setup.md, or
  • Jump to whichever chapter matches what you want to learn, or
  • Install the Langfuse skill (/langfuse) to apply the patterns from this workshop to your own codebase.

For the bigger-picture material on each chapter, the Langfuse Academy has a dedicated lesson per module.


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