A prompt for release notes reads: "Don't be too technical. Don't use jargon. Don't make it too long. Don't bury the important changes." The notes come back bland and oddly ordered. What is the best revision?

The principle — A prohibition eliminates one possibility and leaves every other one open. Four prohibitions leave a very large space of compliant, disappointing answers, and blandness is what sits in the middle of it.

Why the key is correct — Anthropic's guidance on steering output is to tell a model what to do instead of what not to do, giving the replacement of "do not use markdown" with a positive description of the wanted prose as its illustration. Applied here, the four prohibitions become one specification: written for existing customers who are not engineers, eight bullets or fewer, no internal component names, with anything affecting existing workflows first. That version says what a good result looks like, which is what the current prompt never does.

Why the others are wrong — Repetition is redundancy rather than emphasis. Telling the model to resolve conflicts leaves the contradictions in place and surrenders the choice. And reordering prohibitions changes nothing about what they fail to specify.

Remember this — Count the "don'ts". Each one is a sentence that never said what you wanted.

Sources — Anthropic, Prompting best practices.