Three tools, three jobs
“AI writing assistant” gets used for almost anything with a language model in it. In practice the tools people mean fall into three groups, and each is built around a different moment in writing.
Chat assistants: write it for me
ChatGPT and similar assistants generate text from a request. You describe what you want in a prompt, usually in a separate window or side panel, and it drafts it: an email, an outline, a summary. They are the most capable of the three and the furthest from your own words, because you edit their draft rather than writing yours.
Grammar and style checkers: fix what I wrote
Tools such as Grammarly work on text you have already written. They flag errors, suggest clearer phrasing and adjust tone. They act after the words exist.
AI autocomplete: help me write it faster
Autocomplete works while you write. It predicts the next few words of the sentence you are typing and shows them inline; you accept with a key or keep typing. It never produces text you did not choose to accept, which is why it is also described as an AI typing assistant rather than a writer. How AI autocomplete works.
Side by side
| Chat assistant | Grammar & style checker | AI autocomplete | |
|---|---|---|---|
| Acts | Before you write | After you write | While you write |
| You give it | A prompt | Your finished text | Nothing; it reads the field |
| It gives you | A draft | Corrections and rewrites | The likely next words |
| Where | Its own window or panel | Underlines or a sidebar | Inline, at the cursor |
| Whose words | Mostly the model's | Yours, adjusted | Yours, typed faster |
| Typically runs | In the cloud | In the cloud | Cloud or on-device |
| Best for | Starting from nothing, summarising | Polishing, catching mistakes | Replies, updates, routine writing |
Product categories are blurring: some checkers now draft text, and some assistants offer inline suggestions. The table describes each job, not every feature of every product.
Which to use when
- A blank page and a deadline: a chat assistant for the first draft.
- An important document you have written: a checker for a final pass.
- The fifty small things you type every day, replies, updates, notes, commit messages: autocomplete, because it saves keystrokes without changing who wrote them, and it works in the app you are already in.
- Anything confidential: prefer tools that process text on your device. On-device vs cloud, explained.
Using them together
They do not compete for the same moment, so many people use more than one. A reasonable setup on a Mac is a chat assistant for drafting and research, and system-wide autocomplete for everything you type yourself. WeType is built for the second job: it finishes your sentences in every Mac app, with a model that runs on the Mac, and it does not try to be a chatbot.