Writing Prompt Comments So AI Builds the Right Function

AI coding assistants treat your comments as instructions. A specific one-line comment above a function stub gets you working code; a vague one gets you guesswork.

Some examples

• You write '// returns true if email is valid, else false' and Copilot fills in the regex and return logic.
• Cursor reads your '// fetch user by id, retry once on 500' comment and writes the fetch with retry baked in.
• You write '// debounced search by 300ms' above an empty handler and Claude completes it with setTimeout cleanup.
• Codex sees '// sort tasks by due date, nulls last' and writes the comparator without you spelling out edge cases.

Try it!

Open any project, delete a small function, leave a one-line comment of what it should do, and let Copilot or Cursor refill it.