autonomous-ai/openharness

The ultimate harness for coding agents and beyond.
Claude Code at work. Codex at home. Hermes in the cloud. One command center.
Start with code. Then follow your curiosity and build across disciplines: CAD, circuits, robots, games and music.
Download ·
How it works ·
Beyond code ·
Harnesses ·
Device
Every agent, side by side
Claude Code, Codex, Cursor, OpenCode, Devin, Amp, Copilot and seven more.
Every machine, side by side
Your laptop, home server and GPU box in one window. Link each one with a password.
No SSH keys. No Tailscale. No port forwarding.
Keyboard first
⌘P finds any harness on any machine. ⇧⌘I jumps to the harness waiting on you. ⌘D splits. Every key remaps.
End-to-end encrypted
Code, keys and keystrokes are sealed on your machine. The relay forwards bytes it can't read.
Fast and light
A native app, not Electron. Close it and your agents keep working.
Idle measurements on an M2 Max:
- **⌘N, ⌘O, ⌘T UI:** 11–13 ms median, 15–18 ms p95.
- **Local terminal echo:** 1.1 ms median, 7.2 ms p95, excluding UI rendering.
- **Desktop resources:** ~0.1% of one CPU core and 304 MiB, including terminal rendering and scrollback; agent CLIs and the daemon are excluded.
Desktop results use a Release fixture with 16 terminals and 1,000 scrollback lines each.
See the workflow and resource benchmarks
and remote P2P, TURN and relay results
for workloads, slow tails, connection failures and raw data.
Built the way developers work
- **Real terminals.** Every agent runs in its own tmux pane. Scrollback, colors and keys just work.
- **Your CLIs, as they are.** Harness never wraps an agent. It reads transcripts and uses the vendor's own hooks.
- **A worktree per harness.** Start an agent on its own branch. Your working copy stays clean.
- **Remap every key.** One JSONC file, reloaded on save. Chords up to four strokes.
- **Local models.** Run open-weight models on your own machines with Grid, Ollama, MLX-LM and vLLM.
- **Bytes, not pixels.** Remote terminals stream text peer to peer. No remote desktop.
- **Open source, all of it.** App, CLI, daemon, relay and device, in this repo.
How it works
In the workspace, a **harness** is one running session of an agent such as Codex
or Claude Code, with its own conversation and working context. A **tab** groups
harnesses. Use **New Harness** to start one and **New Tab** to group work.
Harnesses in the same tab can message each other with harness send: **Agent Messages**,
an experiment of your account, off by default and turned on in Settings ▸ Experimental.
The Store offers **harnesses** with instructions, tools, and optional viewers for
specific crafts. Install a harness, then start it in your workspace. See the
Naming System for the complete naming rules.
One daemon per machine runs your agents in tmux. It dials out, so no machine opens a port.
Every path is sealed end to end: ChaCha20-Poly1305, X25519 session keys, pinned Ed25519 identities.
Harness picks the best path on its own.
**Direct.** A WebRTC channel between your machines. No server in the path.
**Through Cloudflare.** When a firewall blocks the direct path, the same encrypted channel runs over
Cloudflare's TURN network. Harness keeps trying for a direct path.
**Through our relay.** A fallback while WebRTC negotiates. The relay holds no keys and forwards ciphertext.
The architecture guide has the details.
Get started
**Download the app** for macOS or Linux.
Add a machine. Run this on it, then **Machines → Link Machine** in the app:
**In a terminal:** the same line installs hn — tmux's keys and your ~/.tmux.conf, with every
harness on every machine (hn). The first time, hn signs in and connects the