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herdr

A terminal multiplexer rebuilt around long-running coding agents instead of shell sessions

GitHub★ 47.5kWebsiteherdr.dev
Coding-Agent Harnesses & RuntimesOpen source
Language
Rust
License
Apache-2.0
$curl -fsSL https://herdr.dev/install.sh | sh
IN SHORT

What is herdr?

herdr is a terminal multiplexer rebuilt around long-running coding agents instead of shell sessions. It sits in the Coding-Agent Harnesses & Runtimes category of the AI Coding tools and is open-source, written in Rust and licensed Apache-2.0. To get started: install.

Markdown version ↗

Overview

herdr describes itself as "the runtime your coding agents live on". It is a terminal application, written in Rust and shipped as a single binary with no Electron runtime, that takes the multiplexer idea — panes, layouts, detach and reattach — and reshapes it for work where the thing occupying a pane is an agent rather than a person at a prompt.

The practical difference shows up in three places. Terminals keep running on a background server when the client disconnects, and layouts restore after a restart (the original processes themselves do not survive a reboot). Local work and remote SSH machines are consolidated into one interface, so a fleet of agents spread over several hosts is visible in a single window. And every pane carries a status — working, blocked or idle — which is the piece a normal multiplexer cannot give you, because "blocked waiting for approval" is not something a shell reports.

Agents are treated as first-class clients, not just processes being watched. They talk to herdr through a CLI and a socket API, which lets an agent open its own panes and coordinate with other agents running alongside it. It works with the mainstream coding agents — Claude Code, Codex, Cursor, OpenCode and Grok among them — and is driven either by tmux-style prefix-key bindings or with the mouse. A plugin system with a marketplace covers extensions.

What it does

  • Session persistence: terminals keep running on a background server after the client disconnects, and layouts restore on restart
  • Local machines and remote SSH hosts consolidated into a single interface
  • Per-pane agent status — working, blocked or idle — visible at a glance
  • Agent-native CLI and socket API: agents create their own panes and coordinate with each other
  • Works with Claude Code, Codex, Cursor, OpenCode, Grok and similar tools
  • tmux-style prefix-key bindings plus mouse interaction
  • Single Rust binary, no Electron; plugin system with a marketplace

Getting started

herdr installs as one binary. The commands below come from the project README.

Install

The install script covers macOS and Linux.

bashbash
curl -fsSL https://herdr.dev/install.sh | sh

Or install with a package manager

Homebrew and mise are both supported; a PowerShell install script is published for Windows, and binary releases are available for several architectures.

bashbash
brew install herdr
# or
mise use -g herdr

Start it

Running the binary with no arguments opens the multiplexer.

bashbash
herdr

Detach and reattach

Detaching leaves the server — and the agents in it — running. Re-running `herdr` reattaches to the same layout.

bashbash
ctrl+b q   # detach
herdr      # reattach

Run your agents in panes

Launch a coding agent inside a pane as you normally would; herdr tracks whether it is working, blocked or idle, and the agent can open further panes through the CLI and socket API.

bashbash
claude
# or codex, opencode, cursor-agent, …

Commands and code are distilled from the project's own documentation — always check the official repo for the latest.

When to use it

  • Reach for it when several coding agents run at once and you need to see which ones are blocked on you
  • Reach for it when agent work spans local and remote SSH machines and you want one window over all of them
  • Reach for it when long-running agent sessions must survive a disconnect or a client restart
  • Reach for it when you want agents to open and coordinate their own panes rather than driving a multiplexer by hand

How herdr compares

herdr alongside other open-source coding-agent harnesses & runtimes tools AI/TLDR tracks, ranked by GitHub stars.

ToolStarsWhat it does
CC Switch★ 151kA cross-platform desktop app that manages provider configuration for eight coding-agent CLIs from one place, with a local failover proxy, MCP and skill management, and spend tracking.
Oh My OpenAgent★ 70.6kOpinionated agent bundle for OpenCode and Codex CLI that ships preconfigured sub-agents, lifecycle hooks and built-in MCP servers behind a single ultrawork command.
herdr★ 47.5kA terminal multiplexer rebuilt around long-running coding agents instead of shell sessions
oh-my-claudecode★ 40.5kA plugin and CLI that adds multi-agent orchestration to Claude Code: staged autopilot workflows, parallel tmux workers, and advisors that route a second opinion to Codex, Gemini, Grok or Cursor.
AionUi★ 34kAn open-source desktop workspace that pairs a built-in agent engine with dozens of external CLI agents, adding scheduled runs, MCP tools and remote access from a WebUI or chat apps.
cmux★ 28.7kA Ghostty-based macOS terminal built around coding agents: vertical tabs that show git branch, PR status and ports, attention notifications when an agent needs you, and a scriptable built-in browser.
cc-connect★ 16.2kA Go daemon that bridges local coding agents — Claude Code, Codex, Cursor Agent, Gemini CLI, OpenCode, Kimi CLI and more — to Feishu, DingTalk, Slack, Telegram, Discord, LINE and WeCom, so you drive them from chat.
Claudian★ 15.9kAn Obsidian plugin that runs Claude Code, Codex, Grok Build, OpenCode, Pi or DeepSeek Harness inside your vault, with the vault as the agent's working directory, inline edits, tabs and cross-session messaging.