5.2. Engineering Prompts for Performance
💡 First Principle: Beyond individual tactics, prompt engineering rests on a few durable principles — clarity, relevance, decomposition, iteration — and on understanding the process flow (including how Chat history feeds back into each new request). Principles let you reason about novel cases; tactics only handle the ones you've memorized.
Why this matters: the exam separates "best practices" (tactics) from "principles" (the reasoning underneath) and "process flow" (the mechanics, including chat history). Questions here ask you to explain why a technique works or how a conversation's history shapes a follow-up answer.
The mental model: a coach versus a playbook. Best practices are plays; principles are the coaching judgment that tells you which play fits a situation you've never seen.
⚠️ Common Misconception: "Copilot Chat ignores earlier messages in the conversation." Chat uses conversation history as part of the prompt it builds, so prior turns shape later responses — which is why follow-ups work and why stale context can mislead.
