Open any chat tool and paste: 'Write a 3-sentence product update. Must NOT include: exclamation points, the words revolutionary/seamless/game-changing, or any invented metric.' You're done when the output violates none of the three bans — or you caught the violation and called it out.
How-to · INT · INT.2
Say what NOT to do — negative constraints work
Explicit must-nots (no hype words, no invented stats, no preamble) shape output as much as positive instructions.
Worked example
Everyone tells the model what to do. Pros also tell it what not to do: no invented numbers, no buzzwords, no apologies, no preamble. Negative constraints are how you kill the tells that make drafts sound machine-made.