From messy inputBriefs & requirementstext
Turn a vague brief into testable acceptance criteria
Makes scope and success concrete without adding imaginary requirements.

Ready to use
Prompt
Here is the brief: [BRIEF]. Separate explicit requirements, likely implications and open questions. Draft user-visible acceptance tests in Given/When/Then language for only the explicit requirements. Add negative and mobile/accessibility cases where relevant. Flag every invented assumption for approval; do not quietly expand scope or promise a completion date.