Multiplex AI agents in persistent terminal sessions

herdr describes itself as "the runtime your coding agents live on." It is a background server that hosts terminal panes rather than a terminal emulator itself: agent sessions keep running when you close the lid, drop the network, or restart the machine, and you reattach to the same panes afterward from any terminal, including over SSH. Every pane is marked working, blocked, or idle, so instead of scanning windows for the one that's stuck waiting on an answer, herdr flags it directly.

It is agent-native by design: the CLI and its socket API are the same surface agents themselves drive - an agent can spawn new panes, prompt another agent, or wait until a different agent is genuinely blocked before acting. herdr doesn't wrap or replace the coding agents it hosts (Claude Code, Codex, Cursor, opencode, Grok, and others); it owns their terminals rather than emulating them, so whatever CLI you already run keeps working as-is.

Use it when you're running multiple coding agents in parallel and need sessions to survive disconnects, want to reattach to in-progress work from a different machine, or want a fast, at-a-glance read on which agent needs your attention versus which is still working. The interface supports both tmux-style prefix keys and direct mouse interaction (click, drag, split), so it fits either a keyboard-only or mouse-driven workflow.

Don't reach for it if you only ever run one agent in one terminal session with no need to detach and reattach - the value here is specifically in long-running, multi-pane, multi-agent sessions that need to persist independent of any one terminal window staying open.

Inputs are the terminal commands and coding-agent CLIs you already run inside herdr's panes; herdr's own output is the pane state (working/blocked/idle) plus the socket API surface that agents use to spawn panes, send prompts to each other, or poll for another agent's blocked state. Sessions and their state persist across disconnects and machine restarts.

herdr hosts existing coding-agent CLIs directly - Claude Code, Codex, Cursor, opencode, and Grok are named explicitly - without wrapping or replacing them. A plugin system extends panes and workflows beyond the built-in feature set, with a marketplace of available plugins. It ships as a single Rust binary with no Electron dependency, so it runs in whatever terminal you already use.

Developers running multiple coding agents at once who need sessions that outlive a closed laptop lid or a dropped connection, and who want a single place to see which agent is stuck and needs a response versus which is still working unattended.

herdr is licensed under the Apache License 2.0.