FlyCrys

⚠️ No longer actively developed

On June 30, 2026 Anthropic released an official Claude Desktop app for Linux (download · docs), covering Ubuntu and Debian on x64 and arm64 with the same Chat, Cowork and Claude Code experience as macOS and Windows.

FlyCrys existed because there was no native Linux GUI for Claude Code. Now there is one, built by the people who make Claude Code itself. There is no point in maintaining a copy and competing with the original, so development has stopped.

The repository stays online as an archive: the code still builds and the last release still works, but expect no new features, no bug fixes and no support. If you are here looking for a Linux desktop for Claude, use the official app.

Thanks to everyone who starred, filed issues and sent patches.

Native Linux GUI for Claude Code agents. One binary, starts in under a second, no Electron.

Why this exists

I've used Linux exclusively for 30 years. When Claude Code became my daily driver for writing software, the terminal worked but I kept hitting walls: can't preview images, can't see a file tree while the agent works, can't render markdown without switching to a browser, can't juggle multiple project streams without a mess of terminal tabs.

I didn't want Cursor or anything Electron-based. I wanted something native that feels like it belongs on a GTK desktop.

FlyCrys is not an IDE. It doesn't edit files. Agents do. You talk to agents, they write the code. FlyCrys gives you a workspace to manage that workflow: file tree on the left, viewer in the middle, agent chat on the right, terminal at the bottom. That's it.

What makes it different

• Native Linux GUI for Claude Code — Opcode uses webview; when FlyCrys started, Claude Desktop skipped Linux entirely (it no longer does — see the notice above)
• GTK4 native — follows system theme, integrates with GNOME, minimal resources
• Workspace-oriented — not just a chat wrapper; file tree, viewer, terminal, git panel, all wired together
• Agent profiles — preconfigured Security, Research, Default agents with custom system prompts and tool restrictions
• Zero cost — no subscription, no API proxy, uses your own Claude Code CLI
• Single binary — one cargo build, one .deb, done

Install

Debian / Ubuntu (recommended)

curl -fsSLo /tmp/flycrys.deb https://github.com/SergKam/FlyCrys/releases/latest/download/flycrys_amd64.deb
sudo apt install /tmp/flycrys.deb

To upgrade, run the same two commands. The URL always points to the latest release.

Build from source

# Ubuntu / Debian
sudo apt install libgtk-4-dev libvte-2.91-gtk4-dev libwebkitgtk-6.0-dev libjavascriptcoregtk-6.0-dev libsoup-3.0-dev

# Fedora
sudo dnf install gtk4-devel vte291-gtk4-devel webkitgtk6.0-devel

# Arch
sudo pacman -S gtk4 vte4 webkitgtk-6.0

git clone https://github.com/SergKam/FlyCrys.git
cd FlyCrys
cargo build --release
./target/release/flycrys

Prerequisites

FlyCrys requires the Claude Code CLI:

npm install -g @anthropic-ai/claude-code

Features

v0.4.0 in action: the in-view find bar stepping through matches (1 of 6), file-search results carrying the full tree context menu ("Show in Tree"), and an interactive AskUserQuestion card answered inline.

Agent chat

• Streaming markdown rendering (tables, code blocks, lists, blockquotes)
• Tool calls shown inline with spinners
• Interactive multiple-choice questions answered with in-chat cards (Claude's AskUserQuestion tool)
• Pause, resume, stop agent processes
• Session resume across restarts
• Agent profiles with custom system prompts, tools, and model selection
• Image attachments via clipboard paste or file picker
• Drag files and folders into the prompt
• Bookmarks for reusable prompts
• Clickable file paths in responses open in the viewer
• Token usage and session cost in the status bar

Slash commands

Type / in the input to see all available commands with descriptions. Filters as you type.

Discovers commands from ~/.claude/commands/, ~/.claude/skills/, project .claude/, and installed plugins. Full CRUD dialog for managing skills and commands.

File tree

• Lazy-loading tree with system MIME-type icons
• Toolbar: Collapse All, Search (filters across entire project)
• Search results behave like the tree — single-click opens, double-click reveals in tree, right-click for the same menu plus "Show in Tree"
• Live refresh via inotify watcher (preserves expand state)
• Right-click: Copy Path, Add to Chat, Open Terminal Here, Open in Default App
• Drag files onto agent input
• Git status coloring in the file tree (files and ancestor folders)
• Git status panel with color-coded changes

Text viewer

• Three-state mode: Source / Preview / Diff (segmented toggle)
• Syntax highlighting for ~50 languages — every grammar syntect ships, plus bundled TypeScript/TSX, TOML, and Dockerfile
• In-view find bar (Ctrl+F): incremental highlight-all, match counter, Enter / Shift+Enter to step through hits
• Markdown preview in WebKitGTK
• Image preview with scaling
• Git diff with highlighting

Run Panel

• Tabbed terminal panel — multiple shell tabs per workspace
• [+] button creates new bash(N) tabs; drag-reorder supported
• Right-click tab header: Rename, Copy All Text, Add Selected to Chat, Close
• Background task tracking — auto-creates task tabs when Claude runs run_in_background commands
• Task tabs show command, separator, then streamed output from the task file
• Task status indicators: ⏳ running, ✓ completed, ✗ failed (via Claude's task_notification events)
• Lazy tab loading — VTE terminals only created on first focus
• Scrollback preserved across sessions per tab
• Colors adapt to light/dark mode

Workspace

• Multi-tab workspaces, one per project (tabs on top)
• Right-click a tab: Rename, Clone (forks the agent's Claude session via --fork-session), Open session in Claude CLI, Open folder in file manager
• Session persistence: window size, pane positions, open files, agent sessions
• Lazy tab loading: only the active tab builds at startup
• Light/dark theme toggle
• Desktop notifications when agents finish
• Status bar shows the git branch (live via inotify), Claude session id, and working directory — all selectable for copy

Tech stack

Crate	Purpose
gtk4 0.10	UI toolkit
webkit6 0.5	Chat rendering, markdown preview
vte4 0.9	Embedded terminal
syntect 5	Syntax highlighting
pulldown-cmark 0.12	Markdown to HTML
notify 6	Filesystem watcher (inotify)
serde + serde_json	Config persistence, CLI protocol

System deps: GTK4, VTE4, WebKitGTK 6.0, libsoup 3.0

License

MIT. See LICENSE.