Manuals / Prompt Engineering / Ch 10

C · ProductionAdvanced45 min read

10. Evals, golden sets & failure modes

Prompt Engineering · 48 pages source format

Ship prompts like code: version them, test on golden cases, track regressions. Know the failure modes: hallucination, sycophancy, prompt injection.

What you'll learn

  • Eval harnesses
  • Golden sets
  • Failure modes

Build a 10-case eval set

Mix easy, medium, adversarial. Run before/after prompt changes. No vibes-only shipping.

Do this now

10 cases for one prompt. Baseline score. Improve prompt. Re-score.

Clear?

Failure mode checklist

Hallucination (invents facts), sycophancy (agrees with wrong premise), injection (ignores instructions), drift (forgets format).

Do this now

Deliberately trigger each failure mode once. Document the trigger.

Clear?

Checklist