Termio is a terminal-first agentic development environment for macOS, built in Swift under the MIT licence, that gives developers running CLI and TUI coding agents — Claude Code, Codex, OpenCode, Pi, Amp, Cursor, Copilot, Kimi, Antigravity, Crush, Grok, and others — one place to run them and to see which one needs attention.

What it is

Termio is an agentic development environment (ADE) whose interface is a real terminal, because, as the README puts it, that is where the agents already live. It sits in the macOS developer-tooling ecosystem and organises work into projects, one per checkout, with that project's terminals and agents underneath; chats sit above projects as scratch agent sessions that do not belong to any checkout. On first launch it wires up each agent's own hooks, so a session reports working, idle, or needs you — shown as a dot in the sidebar, a menu-bar tray that rings when an agent is blocked, and the same signal on your phone.

The concrete thing it replaces is tmux. Termio is explicitly pitched as a tmux alternative: every session's shell lives in termiod, a daemon, so quitting the app only detaches. Closing the laptop and reopening Termio returns the agent where it was left, same process, same scrollback, and only Close Session (⌘W) actually ends a session. That removes the need to learn a multiplexer just to keep long-running agents alive.

Key capabilities

• Automatic hook installation for each agent on first launch, producing a per-session status of working, idle, done, or needs you, surfaced in the sidebar, the menu-bar tray, and on the phone.
• Daemon-backed persistence through termiod: quitting the app detaches rather than terminates, and Close Session (⌘W) is the only action that ends a session.
• A termio CLI that drives the running app: termio session list, termio session spawn "fix the flaky test", termio session run "pnpm test --watch", termio session send ab12cd34 "1", termio session read ab12cd34 --lines 40, termio session watch, termio session focus, and termio notify.
• Remote sessions over SSH to any Linux VPS: Termio reads ~/.ssh/config and never rewrites it, and Settings ▸ Devices ▸ Set Up copies one binary into ~/.local/bin over SSH, starts the daemon there, and installs the agents' hooks.
• Git worktrees created from the sidebar, one branch per parallel task, nested under the project they came from.
• Split panes with ⌘D for a right split and ⇧⌘D for a downward split, plus optional horizontal tabs enabled in Settings ▸ Appearance ▸ Tabs.
• A file editor with syntax highlighting and autosave, project-wide content search that jumps to the matching line, and a read-only git pane showing the current unified diff.

Who uses it and how

• Developers running several CLI agents in parallel, who need an agent, a dev server, and a shell side by side in one window rather than scattered across terminal windows.
• People who would otherwise adopt tmux purely for session persistence, and who want sessions to survive quitting the app or closing the laptop.
• Remote workflows on a Linux VPS reachable by ssh, where the session lives on the box rather than in the connection: dropping the link does not stop the agent, and reattaching restores the exact screen.
• Agent-to-agent orchestration, where an agent inside Termio spawns a sibling session on a task, answers its permission prompt with termio session send, and reads back the reply with termio session read.
• Mobile monitoring: an iPhone companion beta on TestFlight, paired by scanning the QR code in the Mac app's Settings ▸ Mobile, delivers the same "needs you" signal away from the desk.

Getting started

Download the free macOS disk image from downloads.termio.sh (macOS 14 or later, no account required), or install with Homebrew using brew install --cask termio-sh/tap/termio.

How it compares

Among the tools named in the facts, tmux is the direct point of comparison, and Termio's argument is that session persistence and pane management should not require learning a multiplexer. Within a single daemon-backed app it combines what tmux provides with agent status reporting, worktree management, SSH remote sessions, and a CLI, under the MIT licence and free of charge. It is not a general-purpose multiplexer for non-macOS hosts, since the application itself is macOS-only.

When to use it — and when not to

Choose Termio if you drive several CLI agents on macOS and want persistence, status, and remote execution without assembling them from tmux and separate scripts; be aware that going remote means SSH access to the target box and a binary copied into ~/.local/bin, and that the phone companion is still a TestFlight beta. It is a poor fit for teams on Linux or Windows desktops, or for anyone expecting a full GUI git workflow: the Changes pane is read-only and commit, push, and PR deliberately stay in the terminal. The project also carries a moderately active issue backlog of around 40 open issues, so expect to track upstream changes.

brew install --cask termio-sh/tap/termio

termio .                                    # open the current directory as a project
termio session list                        # who's working, idle, or waiting on you
termio session spawn "fix the flaky test"  # start a new agent session on a prompt
termio session run "pnpm test --watch"     # start a plain terminal session on a command
termio session send ab12cd34 "1"           # answer a sibling's permission prompt
termio session read ab12cd34 --lines 40    # print what's on a session's screen
termio session watch                       # stream status changes as they happen
termio session focus ab12cd34              # bring a session forward in the app
termio session close ab12cd34              # close it
termio notify "the migration finished"      # post a macOS notification

termio session spawn "run the migration" --agent codex --wait

npx skills add termio-sh/termio --skill termio

Mac app        ─ unix/ssh ─┐
TUI (soon)     ─ unix/ssh ─┤
                           ├──► termiod
iPhone         ─ wss ──────┤       │
Android (soon) ─ wss ──────┘       │ PTY
                                   ▼
                            shell / agent