An open-source tmux setup tool published by Shawn Pana. A single curl command installs tmux itself, a custom configuration file, and the tmux-bridge CLI into ~/.smux/, allowing AI agents to communicate with one another across split terminal panes. Claude Code can type a prompt into the Codex session in the neighboring pane, and Codex can send its result back — all without a dedicated API or protocol. Under the hood it is a thin CLI layered on top of tmux’s standard screen-capture and key-sending features, so any agent that can run bash can take part, regardless of type. It is MIT licensed and free to use.
Key Features
- One-command install: Running
curl -fsSL https://shawnpana.com/smux/install.sh | bashsets up tmux (installed automatically if missing), the configuration file, and thetmux-bridgeCLI in one go. Everything lives under~/.smux/, which makes it easy to find later - Reading and writing across panes with tmux-bridge: The CLI is split into small commands —
list(show panes),read(capture a pane’s output),type(enter text without pressing Enter),keys(send special keys such as Enter, Escape, Ctrl+C), andname/resolve(label panes and look them up). Each command does exactly one thing, so you can separate typing from submitting and check as you go - Direct agent-to-agent collaboration: The other agent does not need to expose an API. As long as it runs in a terminal and can invoke bash, CLI-based agents such as Claude Code, Codex, and Gemini CLI can be mixed together
- Distributed as a skill: Running
npx skills add ShawnPana/smuxadds a skill so the agent understands how to usetmux-bridge. The project states support for 40+ agents, including Claude Code, Codex, Cursor, and Copilot - Practical as a plain tmux config too: It ships with Option-key bindings that work without the prefix key, mouse support for selecting panes and text, pane labels, and a pared-down status bar — settings that make everyday tmux use lighter
- Requirements: macOS (Homebrew required) and Linux. tmux 3.2 or newer is required, and the installer sets it up if it is missing
Pricing
| Plan | Price | Highlights |
|---|---|---|
| Open source (MIT) | $0 | All features free to use. No paid tier or separate commercial license |
Pricing is current as of August 2026. Please check the official repository for the latest information.
Pros & Cons
✅ Pros
- Free and MIT licensed, with all source readable — you can review the install script before running it
- Built on tmux, a mature foundation, so there is no proprietary protocol to learn
- The commands are fine-grained: “enter text” and “press Enter” are separate, which helps avoid unintended execution
- Panes can be named, so an agent can specify its target in a form humans can read as well
- Useful as a plain tmux configuration even outside agent collaboration
⚠️ Cons
- No native Windows support; using it means running a Linux environment such as WSL
- Without knowing the basics of tmux (sessions, windows, panes), the first steps are a hurdle
- Because communication happens by reading and writing pane text, long output or elaborate TUIs can lead to missed content or misdirected input
- You are granting agents the ability to send arbitrary keystrokes. Configuring permissions and watching the screen so that dangerous commands are not run unconfirmed is the user’s responsibility
- It is a relatively new project maintained by an individual, so the command set may change
Comparison with Similar Services
| Criteria | smux | Plain tmux (raw send-keys) | tmux-bridge-mcp | Zellij |
|---|---|---|---|---|
| Main use | tmux config + agent-to-agent messaging | Automating arbitrary pane operations | Cross-pane messaging via MCP | Terminal multiplexer |
| Setup | One-command installer | tmux built-ins only (roll your own) | Configured as an MCP server | Package manager, etc. |
| Agent integration | Call tmux-bridge from bash | Requires custom scripts | Called from MCP-capable clients | Not provided as a built-in feature |
| Supported OS | macOS / Linux | macOS / Linux | macOS / Linux | macOS / Linux / Windows |
| Price | Free (MIT) | Free | Free | Free |
Who Is It For
- People running CLI agents such as Claude Code and Codex side by side who keep copying output from one and pasting it into the other
- Teams that want to split work across multiple agents in parallel, for example an implementer and a reviewer
- Those who prefer a lightweight setup that stays within bash commands rather than adding another MCP server
- Daily tmux users who want to quickly tidy up key bindings and pane labeling
Summary
smux repackages tmux’s well-established screen-capture and key-sending features into a small CLI aimed at AI agents. Its biggest strength is letting agents converse without a dedicated API in between, and since installation and removal stay contained in ~/.smux/, it is easy to try. That said, because communication runs through pane text, reliability depends on the use case. Start with a small pairing — a two-pane implementer-and-reviewer setup, for instance — and keep the keystrokes your agents send visible on screen as you begin.