The Prompt Lab — Anchored Rewriting
Learn the anchored rewriting prompting technique with concrete before/after examples.
Anchored Rewriting
The Technique
Anchored Rewriting gives the model an explicit “preservation list” — things it must not change — alongside the things it should improve. Without this, models treat rewriting as a blank check to restructure, rephrase, and “improve” text in ways that strip out intentional choices. By declaring what’s sacred, you get targeted edits rather than a ghost-written replacement.
The Naive Prompt
Rewrite this product description to be more compelling:
"The Kelso flask holds 20oz and is made from 18/8 stainless steel.
It keeps drinks cold for 24 hours or hot for 12. The lid screws on
and won't leak. Available in matte black, forest green, and rust."Why It Falls Short
A model given this prompt will happily punch up the language — but it’ll also invent a brand voice, swap “rust” for “terracotta,” bury the actual specs, and add a call-to-action nobody asked for. The resulting copy may be livelier, but it’s no longer yours — and it may introduce inaccuracies. You wanted polish, not a personality transplant.
The Improved Prompt
Rewrite this product description to be more compelling for an
outdoor/adventure audience.
PRESERVE (do not change):
- All specific numbers: 20oz, 18/8, 24 hours cold, 12 hours hot
- All three color names exactly as written: matte black, forest green, rust
- The lid mechanic described as "screws on" — do not upgrade or embellish this
- Overall length: stay within 10% of the original word count
IMPROVE:
- Opening line — make it active and vivid, not spec-forward
- Tone — confident and tactile, like REI product copy
- Flow — vary sentence rhythm
"The Kelso flask holds 20oz and is made from 18/8 stainless steel.
It keeps drinks cold for 24 hours or hot for 12. The lid screws on
and won't leak. Available in matte black, forest green, and rust."Why It Works
The preservation list creates a hard boundary that prevents the model from “helpfully” drifting — it knows exactly where its creative latitude begins and ends. Naming a concrete tonal reference (“like REI product copy”) calibrates the voice without requiring a lengthy style guide. The result is a draft that still sounds like your product, just better — which is actually what “rewrite” means in a real workflow.
When to Use This
- Marketing and brand copy where legal-approved claims, product specs, or trademarked terms must survive untouched through an editing pass — especially useful in GPT-5.5 Pro or Claude Opus 4.7 workflows where the model’s rewriting instinct is strong enough to matter.
- Editing someone else’s writing where you’re preserving voice, jokes, or deliberate stylistic quirks while tightening structure — telling the model what to protect is faster than correcting what it destroyed.
- Any high-stakes document revision — contracts, grant proposals, medical instructions — where improving clarity in some sections cannot come at the cost of altering precise language in others.