Rewrite in my voice: the Mac app writes in your register

The Mac app has a new feature, and it is the first thing Ghostchars does that writes rather than removes. Rewrite in my voice takes a draft you are about to send and rewrites it to read like your own messages.

You start by importing those messages. They can come from a Slack export, the zip or the folder it unpacks to; from the Sent mailbox of Apple Mail; from a text file; from a JSONL file; or from text you paste into a box. For a Slack export you pick which user is you, and for a mailbox you pick which address is yours. Only your own messages are kept, and the other side of every conversation is dropped before anything is stored. At 60 messages or 2000 words, whichever you reach first, the app measures how you write and keeps a short profile. After that, you paste a draft and the app hands back a rewrite in your register.

The rewrite appears as it is written, with a progress ring and a count of the attempt it is on, and the mark in the menu bar pulses until it is done. The two then sit side by side, your draft on one side and the rewrite on the other, so you read one against the other before anything goes out. The app sends nothing for you and rewrites nothing in place.

The profile is a set of measurements rather than a folder of your sentences. The app counts how often you open a message in lowercase, how often you drop an apostrophe, how long your sentences run, how you use dashes and commas, how often you ask a question, and which openers you reach for.

That distinction carries two things. The first is privacy: a profile of counts cannot leak a message back out, because no message is in it. The second is quality. A model handed a pile of your old messages tends to borrow from them, and what comes back is somebody else's sentence with your name on it. A model handed the shape of your writing puts that shape around the content of your draft instead.

A rewrite that changes your register is the point. A rewrite that changes your numbers is a defect, and it is the failure that makes people abandon this kind of tool after one bad send.

So every rewrite is checked against the draft it came from. The app takes each number, name, link and protected phrase out of your draft and marks it kept or missing in the rewrite. That list sits beside the two texts, so a dropped price, a mangled link or a name that quietly changed spelling shows up before you send rather than after. The app tries up to three times and shows the first rewrite that keeps everything; if none does, it shows the best one with the misses marked rather than pretending.

The check repairs nothing. It reports, and you decide: send the rewrite, edit it, or keep the draft you wrote.

The window is for a draft you are still composing. The menu has a second row for text you have already copied: click Rewrite clipboard in my voice and the rewrite runs without a window opening at all.

When it is done, Copy last rewrite puts the result back on your clipboard with the fact check summary beside it: how many of your facts were kept, and whether the length landed in the band. It is the same check the window shows, reduced to one line.

The rewriting runs on a local model on your Mac, through Ollama, on 127.0.0.1. The app does not install Ollama and does not bundle it: it points you at ollama.com and waits until the model is in place. The model is gemma4:12b, roughly an 8 GB download, and running it wants 16 GB of memory.

That is a real cost, and it buys the thing on the other side of it: nothing leaves the Mac. The messages you import, the profile measured from them, your drafts and the rewrites stay on your own machine, and Forget my voice in Settings deletes all of it. There is no account for this feature, no server of ours in the path, and no draft of yours in anybody's logs.

Here is what the testing showed, including the part that does not flatter it.

In blind panels the rewrite kept every fact in 8 of 8 test drafts, and readers said they would send it as it stood in 9 of 10 cases. Those are the two numbers the feature was built to reach.

Then there is the panel that had read the author's real messages. Shown a real message beside a rewrite, those readers still picked the real one most of the time. Something in how a person writes survives being measured, and this does not capture it.

So the honest description is the narrow one, and it is the description used everywhere else on this site: a rewrite in your register that keeps your facts. It is not an impersonation, it will not pass with people who know your writing, and it is not built to. It is built to save you the twenty minutes you would have spent making a correct draft sound like you.

Importing your messages, building the profile and the whole of setup are free. The rewrite itself is the part a licence unlocks.

The price does not change: $24 once, on up to 3 of your own devices, with every version 1 update included. A licence you already bought covers this, because it is the same licence that lifts the weekly limit on the hotkey and in the browser extension.

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