Overview

Codemux is an agent development environment (ADE). It combines native multi-provider chat, terminal multiplexing, an embedded browser, git integration, and multi-agent orchestration in one desktop application. Agent Chat is the default interface; the classic terminal-first UI remains available in Settings.

What It Does

• Prompt-first workspaces — Describe what you want to do, and Codemux creates a workspace with an auto-generated branch, selected agent, and your task as the initial prompt. Image paste works directly in the prompt input.
• Project management — Open existing repos or create new ones (empty or clone). An onboarding wizard detects your package manager and sets up dependencies automatically.
• Terminal multiplexer — Split panes, multiple tabs, WebGL rendering with Unicode 11 widths. Run AI coding agents (Claude Code, Codex, OpenCode, Gemini, Antigravity, Copilot, Cursor Agent, Amp, Grok, Droid, Mastracode, Pi) side by side. Panes persist across workspace switches so alt-screen TUIs keep their state.
• Agent status indicators — Real-time status dots show what each agent is doing: working (amber), needs input (red), ready for review (green), or monitoring something in the background (cyan). Visible in the sidebar and tab bar.
• Agent launcher — Use the title-bar + menu for Agent Chat, CLI-agent presets, terminals, and browser panes; pin favorite presets for one-click launch. A Run button with Ctrl+Shift+G executes your project's dev command instantly.
• Embedded browser — Hybrid browser with three input tiers: CSS selector, CDP coordinate-based, and OS-level (ydotool / Win32 SendInput) for stealth interaction. Agents control it programmatically. Viewport presets resize the actual viewport via CDP for responsive testing.
• Git workflow — Stage, commit, push, pull, view diffs — all from the right panel. Works with GitHub and GitLab, self-hosted included.
• Code review — Create a pull or merge request, read its checks, leave line-level notes, submit a verdict, answer and resolve review threads, and merge — without leaving Codemux. A dedicated page triages every request across the repos you have open, and failing checks or review comments can be handed straight to an agent.
• Theming — Five dark themes picked live from the command palette, a studio for building your own from two colors or a VS Code import, and per-surface typography.
• Usage accounting — Token and cost totals per provider, model, and day, read from your agent CLIs' own local history.
• AI tools — Generate commit messages with AI from your staged diff.
• Setup scripts — Configure per-project setup/teardown commands that run automatically when workspaces open or close. Docker Compose support built in.
• Auth and sync — Sign in with GitHub OAuth or email/password. Personal settings and user-authored skills sync server-side across devices.
• Web remote access — Use the full Codemux UI from another browser. Pair with a running desktop, or run codemux serve on a displayless machine to boot the same backend without a GUI.
• Agent Chat — Default native conversational pane for Claude, Codex, Cursor, and OpenCode with streaming, mode pills, attachments, provider-authored task plans, live context-window usage, and a unified multi-provider model picker.
• Workflow orchestration — Inside Agent Chat, a Claude Workflow run renders as an in-thread approval/progress card with a per-phase agent drill-in and a /workflow slash command. See Workflow Orchestration.
• Cross-platform — Native Linux (AppImage / .deb / .rpm / AUR) and Windows (NSIS installer) binaries. In-app auto-update covers the AppImage and the Windows NSIS build; .deb / .rpm / AUR update through their package manager.

Architecture

• Frontend: React 19 + Tailwind v4 + shadcn/ui, state via Zustand
• Backend: Rust (Tauri 2), async via Tokio
• Terminal: xterm.js with WebGL rendering (DOM fallback), Unicode 11 widths, kitty keyboard protocol, PTY via upstream portable-pty 0.8.1 (the Windows fork was reverted; the console is hidden by an AllocConsole + SW_HIDE on the parent process)
• Browser: Pure-Rust agent-browser via direct CDP. Hybrid 3-tier input (selector → CDP coordinates → OS-level ydotool / Win32 SendInput), screenshot-based rendering with reactive stream-url reconnect
• Git: Direct git CLI calls from Rust; GitHub via the gh CLI and GitLab via glab
• Agent Chat: AgentProvider trait with three concrete adapters — Claude (Claude Agent SDK via Bun-compiled sidecar), Codex (codex app-server JSON-RPC), OpenCode (Rust-direct HTTP against a managed opencode serve child)

Key Differences

Chat-first, terminal-complete: Native Agent Chat is the default, while real terminal panes remain first-class: they resize, split, and swap fluidly, use WebGL where a startup probe confirms it is beneficial, and fall back to DOM automatically.

Agent-native: Built for AI coding agents. Builtin presets launch any major coding-agent CLI — Claude Code, Codex, OpenCode, Gemini, Antigravity, Copilot, Cursor Agent, Amp, Grok, Droid, Mastracode, Pi — with one click, each in its own skip-permissions mode. Browser automation lets agents test their own output. Workflow orchestration coordinates multiple agents on a single task.

Workspace isolation: Each workspace can use git worktrees so agents work on separate branches without interfering with each other.