Herdr
A terminal multiplexer built for coding agents, one Rust binary under the Apache 2.0 licence, on Linux, macOS and Windows (beta). Each agent runs in its own pane, and each pane shows whether it is working, blocked or idle. It runs the agents you already use (Claude Code, Codex, Cursor, OpenCode, Grok) and exposes them through a CLI and a local socket: one agent can open a pane, write to another agent and wait until it is genuinely blocked. The session survives a detach or a restart, and remote SSH machines show up in the same window. The prefix key is `ctrl+b`, as in tmux. When an agent in a pane you are not watching has finished or is waiting for your answer, Herdr plays a sound (a default one, or your own MP3 files for 'done' and 'needs input') and can show a notification, inside Herdr, in the terminal even over SSH, or through the OS. You can mute the sound agent by agent.
Strengths
- Each agent state (working, blocked, idle) visible on its pane
- A sound when an agent is done or waiting for your answer, set in the `[ui.sound]` section of the config with a separate file for each case: you can leave the screen without missing the moment to come back ([Instagram reel Db_GVNhOnQF](https://www.instagram.com/reel/Db_GVNhOnQF/))
- CLI and local socket: an agent can open a pane, write to another and wait for its answer
- A single binary, sessions that survive detaching, SSH machines in the same window
- Agent agnostic, and the tmux `ctrl+b` prefix so there is nothing to relearn
Limitations
- No automatic worktrees: two agents on the same branch still overwrite each other
- Oversized while you drive a single agent, and unappealing if you do not live in the terminal
- A young project that ships often (version 0.9): shortcuts and API can still move
Best for
- Seeing at a glance which agent is waiting for your approval across several parallel sessions
- Having a second agent review a first one's work, waiting until the first has finished