Edition 10.7 — The builder's eval, one altitude above Chapter 25. Chapter 25 was a three-line smoke detector for a skill's artifact; Chapter 47 is for when the model's output is the product itself. The Anthropic API course ships, as working code, the two tools most builders never build — a way to SCORE output and a way to RETRIEVE the right context. Both ported to TypeScript over a weekend: a PromptEvaluator (synthetic dataset → cheap code-grade + LLM-judge → honest scorecard) and a hybrid BM25+vector retriever. The point isn't the 400 lines; it's that you can stop charging for AI output you can't score.

The builder's eval, one altitude above Chapter 25. Chapter 25 was a three-line smoke detector for a skill's artifact; Chapter 47 is for when the model's output is the product itself. The Anthropic API course ships, as working code, the two tools most builders never build — a way to SCORE output and a way to RETRIEVE the right context. Both ported to TypeScript over a weekend: a PromptEvaluator…