Yuki Writer marks the sentences that are hard to read.

A writing editor for the Mac. It marks long sentences and filler words as you type. A card at the caret explains each mark and offers a fix.

51 words · Reading ease 81 · easy1 very long sentence1 filler word

What it marks

Yuki Writer checks three things. It has no grammar check and no style guide.

Long sentences

A sentence of 20 words or more gets a yellow background. Shorten it or split it in two.

The report that we sent to the team last week covers the budget, the hiring plan and the dates for the next two releases.

Very long sentences

At 30 words the background turns red. Split the sentence up.

When the meeting ended, which was later than anyone had planned because the projector failed twice, we agreed to move the launch to May and to ask the design team for new screens before then.

Filler words

These words rarely add meaning in English. Yuki Writer fades them and strikes them through, so you can still read the sentence.

We actually think the new plan is really quite good.

actuallybasicallyreallyveryjustquiterathersimplyliterallytotallydefinitelycertainlyhonestlyessentiallyfairlysomewhattrulyvirtuallypracticallyabsolutely

The card at the caret

Put the caret in a mark and a card opens below it. The card names the problem and says how to fix it.

On a filler word, Remove deletes the word and the space next to it. On a long sentence, Fix it for me opens the rewrite window. An OpenAI model suggests a shorter sentence. Yuki Writer marks the stretch it took out and the stretch it put in. You choose Use suggestion or close the window.

Fix it for me is the only feature that sends text off your Mac. It sends that one sentence and nothing else. It needs your own OpenAI API key, set as OPENAI_API_KEY.

Also in the app

Reading ease
The footer shows the word count and the Flesch reading-ease score. The score runs from 0 for the hardest text to 100 for the easiest.
Markdown
Bold, italic and code show their formatting as you type. Markdown symbols do not count as words. Press ⌘⇧P for a preview.
Light and dark
The window follows the macOS appearance.
Updates
New versions download in the background and install when you quit or restart. A window then lists what changed.

Questions

Which Macs does it run on?
Macs with Apple silicon.
Which languages does it check?
English only. The filler words are English words, and the Flesch formula counts English syllables.
Does my writing leave my Mac?
Only when you click Fix it for me. Yuki Writer then sends that one sentence to OpenAI. Everything else runs on your Mac.
Why is a sentence marked when it reads fine?
The rule counts words and does not judge meaning. Some long sentences are fine as they are. You can leave those marked.

What's new

  1. Version 0.1.11 November 2026

    • Chisel is now Yuki Writer. A new name and a new icon; your writing works as before.
    • Yuki Writer updates itself. A new version downloads in the background and goes in when you restart or quit.
    • What's new. After an update, this window shows what changed. Open it again from the Yuki Writer menu.

  2. Version 0.1.01 November 2026

    • A writing editor that shows where a text is hard to read. Long and very long sentences are highlighted, filler words faded and struck through, and the caret offers a fix.
    • Fix it for me. A model rewrites a marked sentence and shows it beside the original.
    • Preview. ⌘⇧P shows the Markdown as it will read.
    • A quiet look that follows the system's light and dark mode, with the counts in a footer.

Try it on your own writing.

Download for Mac

Version 0.1.1, for Macs with Apple silicon.