LangChain Agent Harness Engineering Showcase banner
By Cobus Greyling

Master AI Agent
Harness Engineering

10 production-grade tutorials that teach you how to build reliable, observable, and testable agent systems with LangChain.

Browse the 10 Tutorials Read the README
CG
Sole author • No fluff. Pure engineering.
10
Tutorials
Progressive & cumulative
~5h
Total Learning Time
Including exercises
Harness Engineering
Evaluation • Guardrails • State • Observability
Production patterns
Ready to ship

Why most agent tutorials fail you

Most LangChain content stops at “here’s a working agent.” This showcase is different. It teaches you how to build agents you can actually trust in production.

Contracts over prompts
Structured output, explicit schemas, and validation as first-class citizens.
Evaluation is infrastructure
You cannot improve what you cannot measure. Tutorial 07 is mandatory.
Resilience is engineered
Guardrails, retries, budgets, and graceful failure — not afterthoughts.

The 10 Tutorials

Ordered for maximum learning. Do them sequentially.

Each tutorial includes runnable code, exercises, and “Harness Engineering Takeaways”.

Recommended learning path

Fast track: 01 (skim) → 02 → 03 → 04 → 07 (critical) → 10
Deep track: Complete all tutorials in order + do the exercises in each README.
Team use: Treat Tutorial 07 as the forcing function. No agent change merges without passing evals.
Ready to build agents you can trust?
Start with Tutorial 01 or jump straight to the evaluation harness (Tutorial 07).
Start Tutorial 01 Go to Evaluation Harness
Created and maintained by Cobus Greyling — sole author. This is a personal educational showcase focused on real-world agent engineering.
View on GitHub (README) • Markdown version