How to Rewrite Text Anywhere on Mac with AI (No Copy-Paste)

You write all day on your Mac — Slack replies, commit messages, emails, release notes, documentation. And when something needs to read better, the ritual is always the same: copy the text, switch to ChatGPT or Claude, paste it, type “make this clearer,” wait, copy the answer, switch back, paste again. Five context switches to fix one sentence.

There’s a faster way: an AI rewriter that lives where your text already is.

The problem with chat-window AI for editing

Chat assistants are great for open-ended thinking. They’re terrible for quick edits, because editing is in-place work and chat is a separate place. Every round trip costs you the thing that matters most when you’re heads-down: your focus.

The friction also means you skip it. You send the slightly-awkward Slack message instead of polishing it. You ship the commit message with the typo. The tool that’s “only five steps away” is, in practice, too far away to use for the small stuff — which is most of the stuff.

A floating toolbar on your selection

The fix is to bring the AI to the selection instead of bringing the selection to the AI. FavTray’s AI Writer does exactly this: select text in any Mac app and a small toolbar appears right at your cursor with one button that matters — AI Writer — plus the usual Cut, Copy, Paste.

Open it and you get six actions, each a purpose-built prompt rather than a generic chat:

• Polish — improves clarity, flow, and word choice while keeping your meaning and length.
• Format — fixes structure, punctuation, capitalization, and broken line breaks (great for text pasted out of a PDF) without rewording.
• Proofread — grammar and spelling only, minimal changes, your voice intact.
• Make it Funny — a witty rewrite for when the message is too dry.
• Add Emoji — tasteful, relevant emoji without changing your words.
• Write Anything / Write Post — generate a draft from a topic, with an optional line of direction.

The result streams in live so you watch it form, then you decide: Replace the selection, Insert below it, Copy, Regenerate, or Discard. Nothing changes until you choose. Press Esc or click away to dismiss.

Bring your own key — and keep it local

Most “AI writing apps” route your text through their servers and bill you a subscription on top of the model cost. AI Writer doesn’t have servers in the loop. You add your own OpenAI or DeepSeek key (or any OpenAI-compatible endpoint) in Settings, it’s stored in the macOS Keychain, and requests go directly from your Mac to your provider.

That has three benefits:

1. Privacy. FavTray never sees your text or your key. If you point it at a local model via Ollama, nothing leaves your machine at all.
2. Cost control. You pay your provider’s per-token rate, not a markup. DeepSeek in particular makes everyday rewriting nearly free — see DeepSeek vs OpenAI for writing.
3. Choice. Swap models any time. Use a cheap, fast model for proofreading and a stronger one for drafting.

It works in the apps you actually use

Because AI Writer reads your selection through the macOS Accessibility API — with a clipboard fallback for apps that don’t expose it — it works far beyond native text fields:

• Mail and Notes — proofread before you send, format messy pasted content.
• Slack and messaging — polish a reply in the composer without leaving the thread.
• Your browser — clean up text in any web textarea.
• Terminals like Warp — read a selection even though the app renders its own text; Copy and Insert work, and Replace works in editable fields.

Safe by design

Letting an AI touch your text everywhere raises real questions, so AI Writer is built defensively:

• Validation first. Empty or oversized selections are rejected before any network request, so you never wait on a doomed call or run up cost on a 50-page paste.
• Prompt-injection guard. Your selected text is wrapped and the model is instructed to treat it strictly as content — so a selection that happens to contain “ignore previous instructions” can’t hijack the action.
• Password fields are skipped entirely — no synthesized copy against a secure field.
• Your clipboard survives. The full pasteboard (text, images, files) is snapshotted and restored around every read and write-back.

Where it fits

AI Writer is a Pro feature in FavTray, alongside ten other menu-bar tools like the AI usage tracker and reminders you can’t ignore — all 100% local, no account. If you already pay for an AI API, this is the highest-leverage place to use it: not in a chat window you have to visit, but right on the words in front of you.

The best editing tool is the one that’s already where you’re typing. Select, Polish, Replace — and get back to work.