Question

A developer opens a new, empty file and writes a single comment: `// parse a date string and return it`. Copilot suggests a function, but it returns a Date object when the team's convention is to return an ISO 8601 string, and it throws on invalid input instead of returning null. Following prompt-engineering best practices, what is the most effective first adjustment to the prompt to steer Copilot correctly without switching to a few-shot approach?

Accepted Answer

Rewrite the comment to state the exact expected behavior and output format, e.g. `// parse a date string; return it as an ISO 8601 string, or null if the string is invalid`

Answer

Add three fully worked example input/output pairs above the function so Copilot can infer the pattern

Answer

Repeatedly press the keyboard shortcut to cycle alternative suggestions until one happens to return a string

Answer

Leave the comment as-is but rename the file to `dateUtils.ts` so Copilot infers stricter typing conventions