Lesson 12 · 18 min
Capstone: ship a prompt system
Pull it all together. Design a prompt + eval set + production wrapper for a real task.
The brief
You are building a feature for a SaaS product: "Auto-tag incoming customer support emails".
Requirements:
- Input: raw email body (any length).
- Output: JSON
{ "category": one of [billing, bug, feature_request, other], "urgency": 1-5, "language": ISO-639-1 code }. - Must handle: short emails ("halp"), long emails (a wall of context), non-English emails, and prompt-injection attempts inside the email body.
- Cost-sensitive: average email is 200 words. You want < $0.001 per email.