---
title: Harness
description: The keep-pushing loop for your SDLC — what it is, what it does not do, and where to start.
---

`@agentskit/harness` runs one project's software development lifecycle unattended: a vague objective becomes a
PRD, the PRD becomes a design and issues, each issue becomes a contract, a worker in its own worktree, a
reviewed pull request proven against a definition of done, a merge — and, behind a human gate, a release.

It is a CLI and a library. There is no daemon, no dashboard and no database: the state is files in
`.ak-loop/` next to your repository, and the schedule is whatever your machine already uses.

It is free and open source under the [MIT licence](https://github.com/AgentsKit-io/harness/blob/main/LICENSE).

<LoopFactory />

## What the harness decides, and what it does not

The harness orchestrates: what to dispatch, who runs each role, when to nudge, hand off or escalate, what
blocks a merge, and when a batch may be promoted.

It does **not** drive the worker's own model and tool loop. Each worker is an opaque CLI session — claude,
codex, grok, opencode — in its own worktree. The harness hands it a brief and reads what it leaves behind:
three files in `.ak-loop/` that say what it planned, what it ran, and what it proved. The loop advances on
files it can check, never on what a terminal said.

## Where to start

| If you want to… | Read |
|---|---|
| Get it running | [Quickstart](/docs/get-started/quickstart) |
| Understand the shape | [How it works](/docs/get-started/how-it-works), [Stages](/docs/concepts/stages) |
| Know what blocks a merge | [Definition of done](/docs/concepts/definition-of-done), [Phase artifacts](/docs/concepts/artifacts) |
| Spend less | [Cost](/docs/concepts/cost), [Flows](/docs/concepts/flows) |
| Know where it stops for you | [Human gates](/docs/concepts/human-gates) |
| Operate one | [Operating the loop](/docs/guides/operating), [Troubleshooting](/docs/guides/troubleshooting) |
| See it happen | [Examples](/docs/examples/first-loop) |
| Look something up | [Configuration](/docs/reference/configuration), [CLI](/docs/reference/cli), [Events](/docs/reference/events) |

## Requirements

Node.js 22 or newer, a git repository with a committed `HEAD`, at least one coding-agent CLI on `PATH`, and a
tracker the loop can read a queue from. `ak-harness loop doctor` tells you which of those is missing before
anything is dispatched.