What Is AI Text Improvement and How Do You Use It to Rewrite Text in Any App?

Updated

AI text improvement means selecting text you've already written and having an AI model rewrite it, fix its grammar, change its tone, or translate it — in place, without leaving the app you're working in. CapyBro is a Windows 10/11 assistant that does this through a hotkey workflow: select text, press a key, and the result replaces your selection. It fits anyone who writes in multiple apps and wants corrections without copy-pasting into a separate chat window. The trade-off to decide up front is cloud models (better quality, text leaves your machine) versus a local model via Ollama (text never touches the network).

The core workflow: select → hotkey → result

The mechanism is the same everywhere, which is why it works in Word, Outlook, Telegram, Chrome, VS Code, or any program with a text field:

  1. Select the text you want changed.
  2. Press the hotkey (the default shown is Ctrl + Shift + Q).
  3. The AI processes the selection and pastes the result back automatically — the example on the site converts an informal vacation request into a formal one in about 0.8 seconds.

Because it operates on whatever text is selected in the active window, there's no integration to configure per app. If the app accepts typed text, the workflow applies.

What "improvement" actually covers

Text improvement isn't one operation. CapyBro exposes it as a set of prompt templates, each of which can get its own hotkey:

  • Fix grammar — corrects errors without restructuring.
  • Rewrite formally — shifts register, as in the vacation-request example.
  • Make twice shorter — condenses.
  • Translate — the interface supports English, Ukrainian, and Russian, but the underlying models handle many more languages; the response comes back in whatever language you request.

You can create unlimited custom templates, so "improvement" is defined by the prompt you attach to a key rather than a fixed menu.

Cloud vs local: the decision that matters most

This is the choice worth thinking through before you start, because it determines where your text goes.

Cloud (OpenRouter) Local (Ollama)
Models GPT-4o, Claude, Gemini via one account Local model you run yourself
Where text goes Sent to the model provider Never leaves the computer
Best for Highest-quality rewrites, varied models Confidential or sensitive text

The site states that in Ollama mode text never goes to the network at all, and that API keys are encrypted locally with Windows DPAPI, with history stored only on your machine. If your text is confidential, local mode is the condition to check first; if you want the strongest models, cloud is the path.

Reviewing before you commit

Replacing text blindly is the main risk of any in-place rewriter. CapyBro's diff preview is on by default: it shows a side-by-side comparison of the original and the AI result before anything is replaced, and you can accept, regenerate, reject, or hand-edit the result first. Responses also stream in real time, so you can read as it generates and cancel mid-stream.

Setup and availability

  • Platform: Windows 10 and 11 (version 2.0.3).
  • Pricing: A free version exists permanently; Pro is a one-time $9 payment with no subscription. The free version's core is open source under the MIT license.
  • Privacy defaults: Keys encrypted locally, history local-only, no ads or tracking.

If you write across many apps and want corrections without breaking focus, the select-and-hotkey model is the reason to use it. If your text can't leave your machine, set up Ollama first and treat cloud models as optional.