AI Harness Engineering Series — Book 2

Make Your
AI Evaluations
Reliable.

"Uneval'd AI is
untrustworthy AI."

AI Harness Engineering Series

AI Harness
Engineering

Application
Evaluation Harness ▶
Context Engineering
Inference API
Foundation Model

Make Your AI Evaluations
Reliable

Yuen Kit Lai

You've shipped AI.
But is it working?

Most teams ship AI features and hope for the best. This book teaches you to measure — with eval harnesses, test datasets, and regression detection that tell you when something breaks before your users do.

  • You changed a prompt and aren't sure if it got better or worse
  • A model update degraded quality and you noticed weeks later
  • You have no systematic way to compare two prompt versions
  • Your eval is just "it looks good to me"
  • You don't know which test cases actually matter

What's Inside

6 chapters. From first eval to production metrics.

Chapter 1

Quick Start: Your First Evaluation Harness

A minimal eval pipeline running against a real prompt in under an hour.

Chapter 2

Building Test Datasets

Curating inputs with expected outputs. Avoiding leakage. Keeping benchmarks honest over time.

Chapter 3

Scoring Strategies

LLM-as-judge, rubrics, and custom scorers. Choosing the right scorer for your use case.

Chapter 4

Regression Detection

Catching quality degradation when a model or prompt changes. Automated alerts vs human review thresholds.

Chapter 5

Human Review

Routing ambiguous outputs for human review. Designing review interfaces. Closing the feedback loop.

Chapter 6

Metrics Collection

Aggregating scores into a dataset-level signal. Avoiding Goodhart's Law. Trend dashboards that tell you whether your eval suite is working.

"Uneval'd AI is untrustworthy AI."

— Chapter 1: Quick Start

"Your blind spots are in the cases you didn't write."

— Chapter 2: Test Datasets

"It didn't break on deploy. You just noticed there."

— Chapter 4: Regression Detection

"A metric that never changes is not measuring anything."

— Chapter 6: Metrics Collection

The Series

Four books. One complete picture.

Book 1 — Available Now

Make Your LLM API and CLI Tools Reliable

Read more →

Book 2 — Available Now

Make Your AI Evaluations Reliable

This book · PDF · $25

Book 3 — Coming Soon

Make Your RAG Pipelines Reliable

In progress

Book 4 — Coming Soon

Make Your AI Agents Reliable

Planned

Buy Book 2.

6 chapters on building reliable AI evaluation harnesses. Working code, real scenarios, verification steps in every chapter.

$25

PDF · free updates

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