Herdr Is Tmux for AI Coding Agents: One Terminal to Run Claude Code, Codex, and the Rest

Chase AI spends 42 seconds pitching herdr, an open source terminal multiplexer built for running multiple AI coding agents at once. The core idea is that herdr replaces a pile of scattered terminal windows with one interface that shows every agent's status (working, idle, blocked, done) and keeps sessions alive even after you close your terminal. He describes it as tmux for AI agents and demos it live with Claude Code, Codex, OpenCode, and Pi running side by side.

What the Video Claims

The transcript makes six concrete claims about herdr. It is an agent multiplexer that monitors and controls multiple terminals with different agents in one place. It organizes work into spaces. It shows which agent is working, idle, blocked, or complete. It supports tabs. It persists as a server, so closing the client does not kill the sessions. It is fast, lightweight, and runs on Windows and Mac. Each of these claims matches what the herdr.dev site and GitHub README advertise, with one caveat covered below under platform support.

What the Screen Recording Shows

The opening frames show a four-pane herdr layout with Claude Code (labeled "Anthropic's official AI coding assistant"), OpenAI's Codex, OpenCode ("AI coding agent that runs locally"), and Pi ("Personal AI assistant in your terminal") running simultaneously. A sidebar lists spaces and agents.

The mid-video demo is the strongest evidence for the status-tracking claim. The sidebar shows four agents with live states: "herdr / working · claude", "explore / idle · opencode", "llm-proxy / blocked · claude", and "qmp / done · codex". Clicking the blocked agent reveals why it is blocked: a Claude Code session waiting on permission to run cargo sqlx migrate run for a database migration. Clicking the done agent shows a finished Codex run where cargo nextest passed 14 tests. Meanwhile the working agent is a Claude Code session editing the herdr.dev website next to a pane running an Astro dev server through bun.

The video also flashes the herdr.dev homepage, which reads "One terminal. The whole herd." and "agent multiplexer · a binary, not an app", plus a one-line curl install command. The closing frames show the GitHub README with an AGPL-3.0 license badge, 149k downloads, 17k stars, and release v0.7.4.

The Persistence Model

The persistence claim in the video reflects herdr's client-server design. A headless server keeps panes and agent processes alive, and the TUI client attaches to it. Close the client, or lose your SSH connection, and the agents keep running. The homepage extends this with a remote angle: sessions run "on a server that keeps it alive when you close the laptop, and reattach from your phone."

Platform Support, With One Caveat

The video says herdr "runs on both Windows and Mac." The herdr.dev homepage is more precise: Linux and macOS builds are stable, while Windows support is a preview beta installed through a PowerShell one-liner. The site also notes there is no Electron, no account, and no telemetry, which supports the "fast, lightweight" framing. The GitHub repo confirms herdr is written in Rust and dual-licensed, AGPL-3.0-or-later with commercial licenses available.

Practical Notes

Installation on macOS or Linux is a single command, curl -fsSL https://herdr.dev/install.sh | sh, with Homebrew and Nix flake options. Herdr supports a long list of agents beyond the four shown, including Copilot CLI, Cursor Agent, Gemini CLI, and Amp, and exposes a CLI plus a JSON socket API for automation. If your workflow already involves two or more coding agents running in parallel, the status sidebar addresses a real pain point: knowing which agent is stuck on a permission prompt without cycling through every window.

Key Takeaways

• Herdr is an agent multiplexer, a terminal tool that runs multiple AI coding agents in one place, comparable to tmux but aware of agent state.
• Live status tracking rolls every agent up to working, idle, blocked, or done in a sidebar, and the demo shows this catching a Claude Code session stuck on a permission prompt.
• Client-server persistence means closing your terminal does not kill agent sessions; you reattach later, including over SSH or from a phone.
• It is open source and lightweight: a single Rust binary, AGPL-3.0-or-later licensed, with no Electron, no account, and no telemetry.
• Platform support is stable on Linux and macOS; Windows support exists but is preview beta, a nuance the video glosses over.

Resources

• herdr.dev - Official site with install commands, docs, and a live demo of the interface.
• herdr on GitHub - Source repository, 17k+ stars, AGPL-3.0-or-later license.
• Herdr Review: Open-Source Agent Multiplexer for AI Coding - Third-party review covering setup and day-to-day use.
• herdr: manage multiple AI coding agents in one terminal - Walkthrough of the multiplexer's features and workflow.