What Is Herdr? The Runtime for AI Coding Agents Explained

Short answer: Herdr is an open-source "agent runtime" – a background server that holds real terminals open for your AI coding agents, so they keep working when you close the laptop and you can reattach from any machine. It doesn't replace Claude Code, Codex, Cursor or other agent CLIs; it owns the terminals they run in, shows which agent is working, blocked or idle, and lets you manage many agents across many projects in one place. It runs on macOS, Linux and Windows and is licensed under Apache 2.0.

Herdr is often described as "tmux for agents", and that is a fair first picture. Below is what it actually does, how to install it, and when it is worth using – based on the project's own site and documentation (herdr.dev, checked October 7, 2026).

What Herdr does

Agents keep running when you leave

Herdr is not an app you keep open. It runs as a server in the background and the terminals live inside it. If you close the lid or lose the network, the agents keep working. If the machine restarts, Herdr brings the layout back and resumes the agent sessions.

You see which agent needs you

When you run several agents at once, the hard part is noticing the one that stopped to ask a question. Herdr reads every pane and marks each agent as working, blocked or idle, so you go straight to the one waiting on you instead of checking pane by pane.

Agents can drive it too

Herdr's command-line interface and its socket API are the same surface. That means agents themselves can split panes, start other agents, send them prompts, and wait until another agent is actually blocked – instead of sending keystrokes and hoping.

It runs the tools you already use

The project lists Claude Code, Codex, Cursor, opencode, Grok, Copilot, Pi and Hermes among the agent CLIs it detects – 22 out of the box according to the homepage. Herdr doesn't wrap or modify them; your existing setup keeps working, it just stops depending on an open terminal window.

One view over several machines

You can add other machines – a desktop at home, a rented server – over SSH (herdr machine add <name>). Their workspaces and agents then show up next to your local ones, and they keep working when you disconnect. A hosted "Herdr Cloud" that connects machines without SSH setup is announced as coming soon, with a waitlist.

How to install Herdr

On macOS and Linux the project's one-line installer is:

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

On Windows (PowerShell):

irm https://herdr.dev/install.ps1 | iex

The install docs also list Homebrew, Nix and manual installs, plus an endpoint-protected install for Windows machines with security software. As with any script piped into a shell, read it first if your company has rules about that.

After installing, start Herdr, open a workspace for each project, and launch your agents inside it exactly as you would in a normal terminal.

How popular is Herdr?

On October 7, 2026 the Herdr homepage showed 42,441 GitHub stars, about 1.29 million installs to date and 1,548 community plugins, and the team announced a $6M seed round. In Google's US Keyword Planner data, monthly searches for "herdr" rose from almost nothing in early 2026 to tens of thousands per month by August 2026 – it went from niche tool to widely searched name in a few months.

Who Herdr is for

• Developers running several coding agents at once – for example one agent fixing tests, one writing a feature, one running a long data job.
• Long-running tasks – migrations, backfills or refactors that take hours and shouldn't die when your laptop sleeps.
• People working across machines – start on a laptop, check progress from a desktop, keep heavy jobs on a rented server.

If you run a single agent for short tasks in one terminal, you may not need it; a plain terminal or an existing multiplexer is enough.

Herdr vs tmux

tmux (and similar terminal multiplexers) also keep sessions alive and let you reattach. What Herdr adds is awareness of agents: status detection (working / blocked / idle), an API agents can use to coordinate with each other, automatic detection of common agent CLIs, session resume after a reboot, and a multi-machine view. The project has a Compare section on its site if you want its own side-by-side.

Things to keep in mind

• Herdr gives agents a place to run unattended. Agents that can run shell commands without you watching should still have sensible permissions – review what each agent is allowed to do.
• The Cloud feature is announced but not yet available; today, connecting machines uses SSH.
• Herdr manages agents, it doesn't provide a model. You still need access to the agent tools and models you use (for example a Claude or OpenAI plan).

FAQ

Is Herdr free?

Herdr is open source under the Apache 2.0 license and installs for free. The agent tools and AI models you run inside it have their own pricing.

Does Herdr work on Windows?

Yes. The project ships one binary for macOS, Linux and Windows and offers a PowerShell installer.

Which coding agents work with Herdr?

The homepage names Claude Code, Codex, Cursor, opencode, Grok, Copilot, Pi and Hermes and says 22 agent CLIs are detected out of the box. Because Herdr only owns the terminal, other CLI tools run in it too.

Is Herdr the same as tmux?

No. It plays a similar role – terminals that survive disconnects – but is built for AI agents: status per agent, an agent-usable API, session resume after restarts and multi-machine workspaces.

What happens if my laptop goes to sleep?

The Herdr server keeps the terminals and agents running in the background; when you come back (from that machine or another), they are where you left them. For jobs that run many hours, the project also suggests running agents on a desktop or rented server and connecting it to Herdr.

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