Learn · Harness Engineering

Open a spec. Walk away.

The autonomous loop

A spec, built by a team of agents.

Normally this is four people: one writes the spec, one checks the design, one builds it, one reviews it. Agentum hands each job to an agent and runs them as phases the server tracks. It doesn't stop to ask what's next. You start it once, walk off, and come back to a change that's already been through review.

phase 01

Authoring

PM agent

Clarifies the spec into checkable acceptance criteria.

phase 02

Architecture

Architect agent

Validates the design and writes it down before any code.

phase 03

Executing

Developer loop

The verify gated feature loop builds each item, one at a time.

phase 04

Review

Reviewer agent

Reads the change, raises concerns or signs it off.

phase 05

Done

verified

Every gate green. A human stop is opt in, never the default.

Inside the developer phase

Watch a feature go green.

The agent gets exactly one feature. It writes the code, stops, and verify.sh runs. Green? Locked in, on to the next. Red? The failing output goes straight back to the agent, which tries again until it passes or hits max_retries. A shell script calls it done, not the model's mood.

agentum · harness runlive
agentum harness run .agentum-harness/
init.shok · feature refresh-tokencoding
verify.sh … green ✓ → donered  (retry 1/3)
wrote handoff.md · next feature
Red, the failing output goes back to the agent and it retries to max_retries. Green, done, hand off, next feature.
The tmux core

It all runs in tmux.

Agents need a home that survives a closed laptop. Agentum picks the boring, proven one: tmux. The agent lives in a session on a machine you keep, the repo holds the state, and shutting your lid touches neither. You leave; it keeps working.

core · tmux

Walk away without losing your place.

Each agent gets its own named tmux session. Close the lid, switch machines, drop off Wi-Fi, it keeps thinking. Reattach later and you land right where it left off, scrollback and all. No reconnect dance, no lost work.

tmux · sessions on host
claude · auth-refactorattached · 2h14m
codex · api-endpointsrunning · 18m
gemini · docs-passdetached · 41m
opencode · test-suiteidle
Anywhere access

Your agents live where you don't babysit them.

Give Agentum any machine that stays on, a cloud VM, an old desktop in the closet, whatever's handy, and it SSHes in and sets it up for you: tmux, git, the agent CLIs. After that the loop runs day and night, and you look in over a tunnel from wherever you are. Nothing to install on the remote, no ports left open to the world.

access · SSH hosts

The whole terminal, in your pocket.

The daemon speaks an HTTP/WS API behind rustls TLS and a bearer token, and the live pane streams over WebSocket. For browser work, a host-resident Chromium is watched live via a CDP screencast tunnelled over ssh -L. You watch, steer, and unblock an agent from a coffee shop. Your keys and code never leave the host you own.

tunnel · end-to-end encrypted
📱
your phone
anywhere
🖥️
your host
agents in tmux

Run the loop on a host you own.

Agentum is the harness, packaged: one Rust binary that spawns Claude, Codex, Gemini and friends in tmux, keeps them running when you close the lid, and lets you check in from anywhere.