Mac workflows

Run Custom AI Rewrite Prompts in Any Mac App

KeigoButton for Mac saves the edits you repeat as custom buttons and runs them in the text field you are already using. For an instruction you do not want to save, open ✎ and type it once.

7 min read··Written by the team behind KeigoButton

What a custom rewrite does

Create buttons for instructions such as “client-ready,” “keep the meaning but cut the length in half,” “natural English,” or “less absolute.” While writing in Mail, Slack, a browser, Notion, or another Mac app, hover over the bottom bar and press the relevant button. KeigoButton applies it to the selection or focused field, shows the result, and lets you insert it back in place.

Saved buttons versus a one-off instruction

MethodBest forExample
Saved buttonAn edit you repeatClient-ready / Shorter / Natural English
One-off ✎ instructionUnique constraints this timeKeep three points and stay under 80 words
Use a short button name. In the underlying instruction, state the audience, constraints, and exact output you want.

Use a selection, the whole field, or an empty field

  • Rewrite one passage: Select the exact text before pressing a button. The rest of the field stays in place.
  • Rewrite the whole field: With no selection, KeigoButton uses the text in the focused field.
  • Compose from empty: In an empty field, open ✎ and enter a brief such as “decline the meeting, health reason, notes already shared.” KeigoButton drafts new text from those facts.

Mac apps expose text fields in different ways. The result panel therefore shows the safe action available for the current destination: Insert, Insert here, or Copy. KeigoButton never sends the email or message automatically; you review and submit it yourself.

Examples of useful saved buttons

Client-ready

Before

I saw the deck. Fix this section and send it again today.

After

I reviewed the deck. Could you update this section and resend it today?

Instruction: Make this appropriate for a client. Preserve the request and deadline; do not add an apology.

Natural English

Before

I want to confirm if you already could check the new contract.

After

I wanted to check whether you’ve had a chance to review the new contract.

Instruction: Rewrite as concise, natural workplace English. Keep the meaning and avoid advanced vocabulary.

Shorter

Before

Based on everything we have been able to confirm at this point in time, there do not appear to be any issues that would have a significant impact on the schedule.

After

At this point, we have found no issues that would affect the schedule.

Instruction: Keep the factual caution, remove repetition, and reduce the length by about half.

How to write a reusable instruction

  1. Name the audience and situation. “For a first email to a client” gives the model a clearer standard than “make it better.”
  2. State what must not change. Preserve dates, names, the decision, number of bullets, or other facts that matter.
  3. Define the output. Ask for body text only, one subject line, fewer than 100 words, or another concrete shape.
  4. Do not combine unrelated jobs. Translation, summarization, research, and tone correction in one button create an unclear success criterion.

How it differs from prompting ChatGPT every time

The normal chat workflow is to copy text, open a chat, type the instruction, copy the answer, return, and paste. KeigoButton stores the recurring instruction once and runs it from the field containing the text. The benefit is greatest for short, repeated edits. ChatGPT remains better for research, planning an entire document, or refining a complex answer through conversation.

Compatibility and limitations

KeigoButton supports Apple silicon and Intel Macs on macOS 14 or later. It needs Accessibility permission to read and replace text in other apps, which some managed work Macs do not allow. There is no Windows version, local-only mode, or bring-your-own-key option. AI output can be wrong, so verify it before sending.

Draft a reply from an incoming message you copyUse explicit copied context to create a complete response without letting the app read your screen.

Frequently asked questions

What can I save as a custom rewrite button?

You can save instructions for tone, grammar, brevity, natural English, translation, formatting, follow-ups, and other text transformations. Saved buttons work best for repeatable editing rules, not open-ended research.

Can I rewrite only selected text?

Yes. Select the passage before running the instruction. If nothing is selected, KeigoButton uses the whole focused field instead.

Can it write into an empty field?

Yes. Open ✎ in an empty field and enter the purpose, facts, and tone as a one-off instruction. Saved buttons are best for repeated edits; ✎ is best for unique drafting constraints.

Does it send the generated message automatically?

No. KeigoButton shows the result for review and lets you insert or copy it. You remain responsible for the final send action.

How much does the Mac app cost?

The free plan includes 50 rewrites a month. Pro includes up to 1,000 rewrites and costs $12 a month or $120 a year on the English interface.

Try it on your Mac

Free for 50 rewrites a month, no card required. Supports Apple silicon and Intel on macOS 14 or later.