Comparisons
When Apple Intelligence Writing Tools is not enough
Start here: if Writing Tools does what you need, use it. It is free, it is already installed, and much of it runs on-device. This page is only about the four specific walls people hit.
The four walls
1. You cannot add your own instruction
Writing Tools gives you a fixed set: Proofread, Rewrite, Friendly, Professional, Concise, Summary, and a few list and table conversions. That is a good default set and a hard ceiling. There is no way to add "rewrite this as a follow-up that does not sound desperate" and keep it as a one-press action.
This is the wall most people actually hit, and it is the reason the whole category of custom-prompt Mac utilities exists.
2. Your Mac is Intel
Apple Intelligence requires Apple silicon. On an Intel Mac, Writing Tools is not an option at all, and a third-party app that does its work in the cloud is the only route. KeigoButton runs on both Apple silicon and Intel, on macOS 14 and later.
3. The language you write in is not well covered
Apple has expanded language support steadily, but coverage and quality still vary a great deal by language, and a general-purpose system feature is rarely tuned for a specific register. Japanese business honorifics (敬語) are the clearest example: the rules are precise, the cost of getting them wrong is social, and a generic "make it professional" action does not encode them.
4. You want the same thing on your phone
Writing Tools exists on iOS too, but it is again the same fixed list. If the point is that your own saved instructions follow you between devices, you need a product built around that.
What to use instead
| If the wall is… | Use | Price |
|---|---|---|
| Custom instructions, pay once | Kerlig (bring your own API key) | $49 one-time |
| Custom instructions, unlimited use | FixKey | $48/year |
| Intel Mac | Any cloud-based tool, including KeigoButton | Free tier available |
| Japanese, or you also write on a phone | KeigoButton | Free for 50/month, then $12/month |
Compare the output against Writing Tools yourselfFree in the browser, no account — then run the same text through Apple's.
Where KeigoButton fits
KeigoButton is for the first wall and the fourth: you write the instruction once, it becomes a button, and the same button is there on the iPhone keyboard. It also runs on Intel Macs, which Apple Intelligence does not. Where Apple wins and will keep winning is price and integration — it is free and it is already there.
Frequently asked questions
Can I add my own custom prompts to Apple Intelligence Writing Tools?
No. Writing Tools offers a fixed set of actions — Proofread, Rewrite, Friendly, Professional, Concise, Summary and some list and table conversions — and there is no way to save your own instruction as a reusable action. Third-party macOS apps such as Kerlig, FixKey and KeigoButton exist largely to fill that gap.
Why is Writing Tools not showing up on my Mac?
The most common reason is hardware: Apple Intelligence requires an Apple silicon Mac, so it is unavailable on Intel machines entirely. Beyond that, check that your macOS version is current, that Apple Intelligence is switched on in System Settings, and that your device language and region are among the supported ones.
Is a paid alternative actually better than the free Apple one?
Only in specific ways. Paid tools let you save your own instructions, usually run on Intel Macs, and often handle particular languages or registers better. Apple Intelligence is free, deeply integrated and partly on-device. If you have not hit one of those specific limits, the free option is the better deal.
Does Apple Intelligence handle Japanese keigo correctly?
It can produce polite Japanese, but a general 'make this professional' action does not encode the distinction between 尊敬語 and 謙譲語, or catch 二重敬語. That distinction is the whole reason KeigoButton exists — you can check the rules it applies for free in the browser at keigobutton.com/keigo-check.
Try it on your Mac
Free for 50 rewrites a month, no card required. macOS 14 or later, Apple silicon and Intel.