How to Use Flowmux: Run Claude Code, Codex, and OpenCode in One Terminal (The Beginner's Guide)

CodexFuse Team · 2026-11-03T14:30:50.720Z · 14 min read min read

How to Use Flowmux: Run Claude Code, Codex, and OpenCode in One Terminal (The Beginner's Guide)

Flowmux is an open-source terminal app that lets you run multiple AI coding agents — Claude Code, Codex, and OpenCode — side by side in one window, with terminal panes, an in-app browser the agents can control, and status notifications that tell you at a glance which agent is working, waiting, or done. In this beginner guide you will learn how to use Flowmux: the critical flowmux.org vs flowmux.dev name check, how to install it on Linux and macOS, how to run your first multi-agent session, and how Session Flow, team workspaces, and AgentOffice fit together.

If you are new to AI coding agents themselves, start with our Claude Code beginner guide before this one. The short version of this guide: confirm you are on flowmux.org (not the unrelated flowmux.dev), run the installer with curl -fsSL https://flowmux.org/install.sh | sh on Ubuntu 24.04+ (or the DMG preview on Apple Silicon Macs), then launch your agents in tabs and split panes to run them in parallel. The rest of this guide walks through every step, including the two traps that catch almost every beginner.

What Is Flowmux, Exactly?

Flowmux is an "Agent Workflow Multiplexer Terminal" — a desktop terminal app for running AI coding agents on Linux and macOS, with workspaces, notifications, and a browser agents can control. Its own tagline is "Go with the agents' flow." When people search for "flowmux ai agents," this is what they mean: one Flowmux window hosting several AI coding agents at once, each in its own pane or tab. It is open source under GPL-3.0, free (the site lists a price of 0 USD), and its pitch is one line: "Run Claude Code, Codex, and OpenCode with terminal panes, browser control, and task signals." (flowmux.org and the flowmux-ai/flowmux README, fetched November 3, 2026)

The single most important beginner fact is that two unrelated products are both named Flowmux. This guide is about flowmux.org — the flowmux-ai project, a GTK4 desktop terminal app. There is a second, separate project at flowmux.dev — grouzen's MIT-licensed Rust TUI that coordinates tmux panes. The two are different products with different licenses, different install commands, and different feature sets, and flowmux.dev currently outranks flowmux.org on the exact query "how to use flowmux." Always check you are on flowmux.org before installing; everything in this guide — the curl installer, the DMG, Session Flow, the browser — is the flowmux.org product.

How Does Flowmux Work? The 60-Second Tour

Flowmux is a native terminal window where each AI coding agent gets its own pane or tab instead of each needing its own separate terminal. You launch your agents in terminal tabs, split panes right or down when you want agents side by side, and zoom into a single pane when you need focus.

The features that make it more than a pane manager:

• Agent notifications. The agent list shows which agent is working, waiting for your approval, or done — the working → attention → done signal flow, so you can tell at a glance where your attention is needed.
• Overview mode (Ctrl+Alt+K). Shows every workspace at once, so a fleet of agents stays visible instead of scattered across windows.
• An in-app browser the agents control. Agents open a page, read it, fill in fields, and click through it using the flowmux CLI — the flowmux browser snapshot command lets you see what they see.
• Code Review (Ctrl+Alt+E). Add comments to code or whole files, then send feedback with code context to a running agent.
• Files, worktrees, and usage. Browse the repo and open files in the built-in editor, and check Claude and Codex usage with Ctrl+Alt+U.
• Terminal search (Ctrl+Alt+Shift+F). Search across workspaces and tabs in one action.
• SSH workspaces. Right-click the side panel for a new SSH workspace, or run flowmux ssh connect user@host.
• Session Flow. Fork a running agent session into a split pane with the same history — try a different approach without losing the main thread.
• Team workspaces. Give one lead agent a task and it delegates to Claude Code and Codex workers in visible split panes.
• AgentOffice. A pixel-art office where you can watch your agents at work — select a room to look closer, or click a character to jump to its terminal.

That list is why the product's own pitch names three things: terminal panes, browser control, and task signals. They are the three things you actually do in it every day.

Before You Install: What You Need

Flowmux is a young project — its download counter reads 404 with the last count on November 3, 2026 — so check the requirements before you begin. Here is what the vendor site and README state.

Two things to take from this table: macOS users are on a preview build with real caveats (Homebrew dependencies, Gatekeeper, no Intel build), and the product is days-to-weeks old, so you are installing early software. The installer does ask before installing missing dependencies, which keeps the first run friendly.

How Do I Install Flowmux?

Installation takes about five minutes on a supported system. Follow these steps in order.

1. Confirm your OS is supported. Ubuntu 24.04 or newer on x86_64, or an Apple Silicon Mac. If you are on Windows or Intel macOS, stop here — there is no build for you yet.
2. Confirm you are on flowmux.org. Do not confuse it with flowmux.dev — the similarly-named Rust/tmux project. This guide's installer, DMG, and features are the flowmux.org product only.
3. Run the installer: curl -fsSL https://flowmux.org/install.sh | sh. The installer asks before installing any missing dependencies. As with any curl-piped-to-shell install, this is the standard caution: the site carries a "SHA-256 verified" badge and every release binary on GitHub ships a .sha256 sidecar, so you can verify the downloaded artifact yourself.
4. macOS users: open the Apple Silicon DMG and drag Flowmux.app to Applications. Make sure the Homebrew GTK4, libadwaita, and vte3 libraries are installed under /opt/homebrew first.
5. Open Flowmux and launch your agents in terminal tabs. Each tab runs one agent; you will arrange them into panes in the next section.
6. Check your setup: run flowmux doctor to diagnose setup issues, and flowmux fix to repair integrations. Run doctor first whenever something looks off — it exists precisely for that.
7. Verify the download (optional). Every binary download on the GitHub releases page has a .sha256 sidecar file for checksum verification.

The whole flowmux flowmux install arc is: confirm OS, confirm site, install, open, doctor-check. The two steps beginners skip are the site check and the doctor run — and those are the two that fix ninety percent of first-run failures.

Your First Session: Run Multiple Coding Agents in One Terminal

This is the core use case: running Claude Code, Codex, and OpenCode in one terminal at the same time, each visible in its own pane. Our OpenCode beginner guide covers the OpenCode side of this trio if you have not used it yet.

1. Open Flowmux and launch Claude Code in the first tab. Authenticate the agent exactly as you would in a normal terminal — Flowmux reuses your existing agent setup.
2. Split the pane to the right and launch Codex there. Now both agents are visible side by side in one window.
3. Open a second tab for OpenCode. Tabs are for task groups; panes are for parallel work within one task.
4. Give each agent work and watch the signals. The agent list shows working, then attention when an agent is waiting for your approval, then done. Click a notification to jump straight back to that agent.
5. Press Ctrl+Alt+K when you lose track. Overview mode shows every workspace at once — the fastest way to regain situational awareness with several agents running.
6. Check usage with Ctrl+Alt+U. See what Claude and Codex have consumed so you do not burn budget blindly across three agents.

That six-step loop — tab, split, work, watch signals, overview, usage check — is the daily rhythm of the product. Everything else is refinement on top of it.

What Is Session Flow, and When Should You Use It?

Session Flow lets you fork a Claude Code, Codex, or OpenCode session from the terminal menu — right-click, then "Fork session" — and the branch opens in a split pane on the right with the same history. This is Flowmux Session Flow at work: you get two views of the same conversation, with the original keeping its plan while the fork tries the alternative.

Use it when an agent proposes approach A and you want approach B tried without losing A's progress. Do not use it for unrelated work — that is what new tabs are for. Forking is cheap; keeping five forks of the same task open is how you lose the thread, so close forks you are not actively comparing.

Can My Agents Really Use the Built-In Browser?

Yes — this is the feature that separates Flowmux from a plain pane manager. Agents open a page, read it, fill in fields, and click through it with the flowmux CLI. The vendor's own description is literal: agents do the browsing; you watch.

Practically, this means an agent can look up API documentation in a live browser tab, test a form it just built, or verify a rendered page — then flowmux browser snapshot shows you what the agent currently sees. Pair it with the terminal search (Ctrl+Alt+Shift+F) when you need to find a string across workspaces and tabs, and with Code Review (Ctrl+Alt+E) when the agent's output needs your annotation with full code context attached.

What Are Team Workspaces and AgentOffice?

Team workspaces let you give one lead agent a task, and it delegates to Claude Code and Codex workers in visible split panes. To set one up, install Flowmux Team from Options → Skills, then start a "New Team Workspace." The lead plans, the workers execute, and because every worker is a visible pane, you can watch the delegation happen instead of trusting a black box.

AgentOffice is the playful side of the same idea: a living pixel-art office where you watch your agents at work. Select a room to take a closer look, or click a character to jump straight to its terminal. It is genuinely useful as a glanceable dashboard — the "which room is my stuck agent in" view — wrapped in a visual joke.

Can I Run Flowmux on a Remote Server?

Yes, via SSH workspaces. Right-click the side panel and choose "New SSH Workspace," or run flowmux ssh connect user@host directly. The workspace opens on the remote machine while the terminal, panes, and notifications stay in your local Flowmux window.

This is how you keep heavy agent work off your laptop: the remote box does the computing and the local window is just the control surface. If you have never set up a remote server, our what is VPS hosting explainer covers the concept before you rent one. Run flowmux doctor after your first SSH workspace — remote session integration is the area most likely to need the fix-up pass.

Flowmux vs Corgi: The Agent-Terminal Lane in One Table

Flowmux does not exist in a vacuum — there is a whole lane of terminals built for coding agents. The October 2026 eight-workspaces roundup (useaitools.me, fetched this run) lists OpenShell, MIKE, Corgi, Craig CLI, Twine, Halv, EditMD, and Keen Code; it does not name Flowmux, which launched around the same window. The two closest to what Flowmux does:

The draw-the-line: Flowmux is the GTK4 desktop option with the agent-controllable browser and session forking; Corgi is the terminal-native option with WSL support and the clearest status labels; Craig CLI aims at the full task-to-PR arc. Pick Flowmux when you want the browser and the desktop app; pick the others when you want a terminal-native multiplexer.

Five Beginner Mistakes to Avoid

Sources

• flowmux.org — official site: install command, OS support, features (panes/tabs, browser control, Session Flow, AgentOffice, team workspaces), price 0 USD, "SHA-256 verified" badge, downloads counter (404, last counted 2026-11-03 12:46 KST)
• github.com/flowmux-ai/flowmux — README: definition "Agent Workflow Multiplexer Terminal," "Go with the agents' flow," supported agents (Claude Code, Codex, OpenCode, Gemini CLI, Antigravity CLI), keybindings, doctor/fix, "Inspired by cmux; an unofficial reimplementation, not affiliated with cmux"; releases page: v0.13.0 notes, .sha256 sidecars, Debian package/tarball/DMG downloads; repo stats (22 stars, 4 forks, created 2026-05-08, 1,648 commits)
• flowmux.dev — the separate, unrelated Rust/TUI Flowmux (grouzen, MIT) — referenced for disambiguation only
• useaitools.me/blog/eight-workspaces-built-for-coding-agents-2026 (published 2026-10-24) — lane context: Corgi, Craig CLI, Twine, OpenShell, MIKE, Halv, EditMD, Keen Code; Flowmux not named

Frequently Asked Questions

What is Flowmux?

Flowmux is an "Agent Workflow Multiplexer Terminal" — a desktop terminal app that runs AI coding agents side by side, with terminal panes, browser tabs agents can control, and task notifications in one window. This flowmux terminal is a native desktop app rather than a web page. It is open source (GPL-3.0), free, and aimed at developers who run Claude Code, Codex, and OpenCode in parallel.

Which AI coding agents does Flowmux support?

The site's headline trio is Claude Code, Codex, and OpenCode. The project's README additionally names Gemini CLI and Antigravity CLI in its notifications section, so more agents are recognized for status tracking than the headline suggests.

Is Flowmux free?

Yes. The official site lists a price of 0 USD and the project is open source under GPL-3.0-or-later. No paid tier appears anywhere on the site or the GitHub repo.

How do I install Flowmux?

On Ubuntu 24.04+ (x86_64), run curl -fsSL https://flowmux.org/install.sh | sh — the installer asks before installing missing dependencies. Apple Silicon Macs use the DMG preview: drag Flowmux.app to Applications, with Homebrew's GTK4, libadwaita, and vte3 libraries installed. There is no Windows or Intel macOS build.

Is the download safe to install?

Every binary download ships a .sha256 sidecar on GitHub for checksum verification, and the site badges "SHA-256 verified." Two caveats: piping any install script to a shell carries the usual risk (read it or verify the artifact), and the macOS build is ad-hoc signed rather than Apple-notarized, so Gatekeeper may block it on first run.