Margin — annotate & revise

About

Margin turns anything on your screen into something you can mark up — then hands your notes to an AI in a format it understands precisely.
AI losing track of which part you mean? "Change the third paragraph," "fix the pricing bit," "that earlier section" — the model guesses and edits the wrong thing, and every clarification costs you another back-and-forth. Margin fixes that. You highlight the exact text, say what you want done with it, and export a brief where every instruction is anchored to the precise words it points at. The model makes targeted changes instead of guessing.
USE IT RIGHT IN YOUR AI CHAT
Works with any LLM — ChatGPT, Claude, Gemini, and more — because it works on any web page. When the model writes a long answer, highlight the parts you want changed, tag each one, and paste the brief back into the same chat. No more retyping what you meant.
USE IT ON GENERATED PAGES & DOCS
When an AI generates an HTML page, report, or document, open it and mark it up the same way. Your highlights become a clean revision brief you feed back for the next version.
HOW IT WORKS

Click the Margin icon on any page — a chat reply, an article, a generated doc.
Select text — a small menu appears.
Tag it: Edit, Question, Remove, or Note.
Add a comment in the side panel.
Hit Export, copy, and paste back into ChatGPT, Claude, Gemini, or any AI.

WHY THE TAGS MATTER
Each highlight carries its intent into the brief, so the AI knows whether to rewrite a line, answer a question, cut a passage, or just keep something in mind. That makes its revisions far more accurate than a vague "please fix this."
PRIVATE BY DESIGN
Margin runs entirely in your browser. It only activates on the page when you click the icon. Nothing you highlight or type ever leaves your device — no account, no sign-in, no tracking, no servers. Always free.
WORKS GREAT FOR

Revising long AI answers without retyping what you meant
Sending precise, targeted edits back to ChatGPT, Claude, or Gemini
Marking up AI-generated pages, reports, and documents
Reviewing articles, research, specs, and long reads
Turning scattered reactions into one clear set of edits

Open-source friendly and built to stay out of your way until you need it.