Orca vs herdr: 2 Ways to Run a Fleet of AI Coding Agents (and Who Each Is For)

TL;DR

• Orca and herdr are two free, open-source ways to run a whole herd of AI coding agents at once, each on its own branch. They overlap a lot. They differ on exactly one thing: who holds the reins.
• Orca is a cockpit you can see. A desktop and mobile app where you, the human, watch every agent, review its diff, and can even click a button in your live app to feed the agent exactly what you clicked.
• herdr is a terminal an agent can drive. A tmux-style multiplexer whose socket API lets another agent boot, watch, message, and wait on the whole fleet, with no human clicking between windows.
• Rule of thumb: want to see the fleet, reach for Orca. Want to script the fleet, or have an agent run it for you, reach for herdr. Both cost $0 to run.

The thing they both solve

A year ago you ran one coding agent in one terminal and watched it type. That era is over. Builders now run five, ten, even thirty agents at the same time, each on its own copy of the repo, each chewing on a different ticket. The bottleneck moved from "can the agent write the code" to "can I keep six of them straight without losing my mind."

Orca and herdr fix that same problem with the same core trick: a git worktree per agent (a separate checked-out branch on disk, so two agents never overwrite each other), a live readout of who is working, blocked, or done, and a review step at the end. Neither one hosts a model or charges you a cent. You bring your own Claude Code, Codex, or one of a couple dozen other agents, and pay only the subscription you already have. The price of the orchestrator itself, either way, is $0.

So how do you pick? Look at who is meant to sit in the driver's seat.

Orca: mission control you can see

Orca, from Y Combinator startup Stably AI, calls itself an "Agent Development Environment." Picture an air-traffic-control desk with one screen per plane. Every agent gets a tile: its terminal, its worktree, its status. One glance tells you which agent needs a decision and which one is ready to review.

Its signature move is the built-in browser. Say an agent is building a signup form and the submit button sits two pixels too low. In Orca you open the page in its embedded Chromium, click the button, and Orca ships that element's HTML, CSS, and a cropped screenshot straight into the agent's prompt. No copy-paste, no describing "the blue thing near the top, no, the other one." You point, the agent sees.

What Orca does that herdr cannot:

• Click-to-context. Point at any element in a real browser and hand it to the agent. This is gold for frontend and design work.
• Rendered review in-app. Read diffs and browse pull requests, issues, and project boards without leaving the window.
• A phone app. Orca runs on desktop and mobile, so you can check on the fleet from the couch.

herdr: mission control an agent can run

herdr is a terminal multiplexer, think tmux rebuilt for the age of agents, written in Rust. It reached roughly 15,000 GitHub stars and hit #1 on GitHub Trending within its first few months, all from a single full-time developer. Every agent gets a real terminal pane on a background server that keeps running after you shut the laptop. Reattach later from anywhere, including a phone over SSH, and every pane is exactly where you left it.

Its signature move is the mirror image of Orca's. herdr exposes a CLI and a JSON socket API, so a program, or another agent, can drive the whole fleet. An orchestrator agent can start ten coding agents, read each one's screen, type a message into a pane, and block until an agent reports "done," without a human ever touching a mouse. herdr auto-detects whether the agent in a pane is idle, working, blocked, or done, with zero config for over a dozen agents. That one detail is the hook the whole thing hangs on.

Plain example: you write a five-line script that says "start an agent on each of these eight bug tickets, wait for all of them, then ping me." Then you walk away. herdr runs the room. We wrote up the patterns builders converge on in a separate herdr deep-dive.

What herdr does that Orca cannot:

• Be driven by an agent. The socket API means a second agent, or a cron job, can orchestrate the fleet end to end.
• Live headless on a server. Run a fleet on a homelab or cloud box over SSH, detach, reattach, no GUI required.
• Be your actual daily terminal. Panes are just real terminals, so servers, logs, and shells sit right next to the agents.

Where each one taps out

Neither is a superset of the other. The honest limits, side by side:

Orca cannot be your headless, SSH-only daily driver, and it is not built for a second agent to programmatically orchestrate the fleet through a socket API. It is a cockpit for a human, not an API for a robot.

herdr cannot give you Orca's point-and-click visual review: no rendered diff cockpit, no embedded click-to-context browser, no polished touchscreen app. From a phone you get a terminal over SSH, not a tap-friendly dashboard.

Which one is for you

Pick Orca if you are the human in the loop and you want to see everything: diffs, a live browser, pull requests and boards in one window. It shines for frontend and design work, where that click-to-context browser is hard to give up, and for anyone who would rather tap a desktop or phone app than type commands.

Pick herdr if you live in the terminal, run agents on a server or homelab over SSH, and want automation: a script, or an orchestrator agent, that boots, watches, and waits on the fleet for you. It is the tmux power user's answer, and the one to reach for when you want an agent, not a person, at the controls.

Or run both. They are not mutually exclusive. herdr can be the scriptable engine underneath while you review in something visual on top. The overlap is real, though, so plenty of people will pick one and never look back.

The one-line version

Orca puts a human at mission control. herdr lets an agent be mission control. Choose based on whose hands you want on the fleet.

Sources: Orca (stablyai/orca), Orca site, Orca review (DEV), herdr.dev, herdr docs (concepts), herdr review (Bitdoze)