castword

GNOME overlay for AI-powered text rewriting. Press a shortcut from anywhere, paste or speak your text, pick a tone — result is on your clipboard.

Runs as a D-Bus service. GTK4 + Libadwaita. Supports OpenAI, Anthropic, Gemini, and Ollama.

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Install

Arch (AUR)

yay -S castword-gnome-bin

Other packages

Format	Download
Debian .deb	castword-gnome-2026-04-10-00.deb
AppImage	Castword-2026-04-10-00-x86_64.AppImage
RPM	castword-gnome-2026-04-10-00.rpm
Flatpak	xyz.shapemachine.castword-gnome-2026-04-10-00.flatpak
Source tarball	castword-gnome-2026-04-10-00.tar.gz

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Screenshots

From source

Prerequisites: Python 3.11+, GTK4, Libadwaita, uv

# Arch
sudo pacman -S python-gobject

# Debian/Ubuntu
sudo apt install python3-gi python3-gi-cairo gir1.2-gtk-4.0 gir1.2-adw-1

git clone https://github.com/Shape-Machine/castword-gnome.git
cd castword-gnome
make install

make install creates a .venv, installs the package, and registers the D-Bus service, desktop file, icons, AppStream metadata, and GSettings schema.

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Setup

Keyboard shortcut

castword is activated via a custom GNOME keyboard shortcut:

1. Open GNOME Settings → Keyboard → Custom Shortcuts
2. Add a new shortcut:
   • Name: castword
   • Command: castword (or the full path from which castword)
   • Shortcut: Super+Shift+W (or your preference)

The app will prompt you to set a shortcut on first launch if none is configured.

Provider

API keys are auto-detected from your environment — no manual config needed if keys are already exported in your shell config.

Provider	Environment variable
OpenAI	OPENAI_API_KEY
Anthropic	ANTHROPIC_API_KEY
Google Gemini	GEMINI_API_KEY or GOOGLE_API_KEY
Ollama	(none — runs locally)

To store keys separately, create ~/.config/castword/.env:

echo 'OPENAI_API_KEY=sk-...' >> ~/.config/castword/.env

Switch provider and model in Preferences → Providers.

Ollama

ollama serve
ollama pull llama3

Then select Ollama in Preferences.

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Tones

castword ships with seven built-in tones:

Tone	Default	Purpose
Direct	✅	Remove hedging, say exactly what needs to be said
Technical	✅	Structured with headings/bullets, precise language
Professional	✅	Polished and human — emails, LinkedIn, client comms
Social	✅	Punchy, engaging, emoji-ok — posts and marketing
TL;DR	—	1–2 sentence summary
Flirty	—	Fun
Playful	—	Fun

Add, edit, reorder, or toggle tones in Preferences → Tones. Each tone has a name and a fully editable system prompt.

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Development

git clone https://github.com/Shape-Machine/castword-gnome.git
cd castword-gnome
make run

Command	Description
make run	Compile schema locally and launch
make install	Full system install
make clean	Remove __pycache__, .pyc, compiled schema, .venv
make release VERSION=yyyy-mm-dd-NN	Build and publish all package formats

Bug reports and feature requests: github.com/Shape-Machine/castword-gnome/issues