Controlling LLM Prose

How-to guide

How to remove ambiguity from a spec

Problem: A requirement can be read more than one way, and someone will pick the wrong way.

Use when: API contracts, RFCs, acceptance criteria, legal-adjacent prose.

Steps

  1. Replace vague modal verbs with RFC-2119 keywords (MUST / SHOULD / MAY).
  2. Resolve every pronoun—if “it” or “they” could point to two things, name the thing.
  3. Make quantifier scope explicit: what does “all,” “any,” or “only” range over?
  4. Fix one term per concept; never vary “user / account / profile” for elegance.
  5. Enforce consistent present tense for system behavior; eliminate accidental tense jumps.

Example

AmbiguousUsers can usually edit any document, and it should be logged.
UnambiguousEach user MAY edit any document they own. The service MUST log every edit to the audit trail.