What Is CapyBro and How Does Its Hotkey AI Text Rewriting Work on Windows?

Updated

CapyBro is an AI writing assistant for Windows 10 and 11 that rewrites, fixes, or translates selected text in place, inside whatever app you're already using. You select text, press a hotkey, and the result replaces your selection automatically — no copy-pasting into a separate chat window. It's a fit if you write a lot across Word, Outlook, Telegram, a browser, or an IDE and want AI edits without leaving the app. It's not a fit if you're on macOS, Linux, or a mobile device, since the current build is Windows-only.

How the select-text → hotkey → in-place rewrite flow works

The core loop has three steps:

  1. Select text in any program that accepts text input — Word, Outlook, Telegram, Chrome, VS Code, and similar.
  2. Press a hotkey. The default shown in the product demo is Ctrl + Shift + Q, and custom prompts can each get their own hotkey.
  3. Get the result in place. CapyBro sends the selection to the chosen AI model and pastes the response back over your selection automatically.

The demo on the site shows a rough vacation request being converted to a formal tone: the original informal message goes in, and a polished version ("Dear team, I would like to request leave from next Monday through Friday inclusive…") comes back and is pasted automatically in about 0.8 seconds.

Two behaviors matter for how it feels in practice:

  • Diff preview before applying (on by default) shows a side-by-side comparison of the original versus the AI result before your text is replaced. From there you can accept, regenerate, reject, or hand-edit the result first. This is the main safeguard against an unwanted rewrite silently overwriting your text.
  • Streaming responses let you watch the AI type its answer in real time, so you can start reading before generation finishes and cancel mid-stream with one click.

Because the tool operates on whatever text is selected in the active window, it works the same way in every supported app — there's no per-app integration to configure.

Cloud AI vs. local Ollama: how to choose

CapyBro supports two backends, and the choice is mostly about privacy versus model access.

Dimension Cloud via OpenRouter Local via Ollama
Model access GPT-4o, Claude, Gemini through one account Models you run locally through Ollama
Where text goes Sent to the cloud model provider Never leaves your computer
Setup Connect an OpenRouter account Run Ollama locally
Best for Broad model choice and capability Confidential or sensitive text

The site states that in Ollama mode, text never goes to the network at all. If your work involves confidential material and you can't send it to a third-party API, local mode is the option that satisfies that constraint. If you want access to frontier cloud models without managing multiple accounts, OpenRouter gives you GPT-4o, Claude, and Gemini under one account.

A practical middle path the product supports: assign a separate model per prompt. That means you can route routine tasks (grammar fixes) to a cheap or local model and reserve a stronger cloud model for tasks that need it.

Setting up custom prompt templates with their own hotkeys

Beyond the default rewrite action, CapyBro lets you create unlimited template commands, each with its own hotkey. Examples given on the site include:

  • "Fix grammar"
  • "Translate"
  • "Rewrite formally"
  • "Make twice shorter"

The workflow is: define the prompt once, bind a hotkey to it, then reuse it by selecting text and pressing that key. This turns recurring editing tasks into single keystrokes rather than re-typing instructions each time.

The interface supports three UI languages — English, Ukrainian, and Russian — switchable instantly. The AI models themselves support many more languages; the response comes back in whatever language you request in the prompt.

Privacy and data handling

The privacy-relevant details stated on the site:

  • API keys are encrypted locally using Windows DPAPI.
  • History is stored only on your computer.
  • In Ollama mode, text never goes to the network at all.
  • The free version's code is open source on GitHub under the MIT license, so anyone can verify what the program does — which the site frames as especially relevant for confidential text.

If your decision hinges on whether text leaves your machine, the determining factor is which backend you configure: cloud (OpenRouter) sends text to a provider, local (Ollama) does not.

Free version vs. the $9 Pro upgrade

The site describes the free version as "free forever" and Pro as a one-time payment of $9, no subscription. The free version's core is open source under MIT.

The page evidence does not enumerate a full feature-by-feature free-versus-Pro comparison, so the exact boundary between the two tiers isn't fully specified in the available material. What is stated: the free version exists permanently, Pro is a single $9 purchase rather than a recurring charge, and the free version's code is open and verifiable.

Practical notes before you install

  • Platform: Windows 10 and 11 only (current version listed as v 2.0.3).
  • The hotkey approach assumes text is selectable in the target app — it works in any program with text, per the site.
  • Keep diff preview on if you're editing text you can't easily recover, since it lets you review before the replacement is applied.
  • Power-user toggles live under Settings → Additional features; most are off by default, so enable only what you need.