Open-source agent infrastructure

Give coding agents a real place to work.

HAR turns any repository into a reproducible workspace with isolated worktrees, project-owned commands, and evidence that changes actually pass.

Get started View on GitHub

Works with

Claude CodeCursorCodexAny MCP agent

Agentrequests task

⌘

Repositoryreads .har/

Create slotisolated worktree

✓

Launch stackports + services

✓

Make changesinside worktree

Verifyproject checks

✓

Validated branchlogs · artifacts · tree hash

ready

Read the project contractAgent discovers the repository through .har/

Create an isolated slotFresh worktree, ports, services, and environment

Launch, change, verifyRun the same workflow your team trusts

✓

Hand off evidenceLogs, artifacts, exact validated tree hash

deterministic workflowhar env verify 3 --full

agentSlots4

last runpassed in 31.2s

Project-owned

The workflow lives with the code, not inside a vendor dashboard.

Agent-agnostic

One stable contract for CLI users, MCP agents, and future tools.

Evidence-first

Every run can leave logs, artifacts, status, and a validated tree hash.

The missing operating layer

Your agent should not have to rediscover how your repository works.

Most coding agents are good at editing files. The hard part is everything around the edit: launching the stack, isolating parallel work, running the right checks, and producing a trustworthy handoff.

01 / Contract

The repository explains itself.

HAR scaffolds a human-readable, machine-readable .har/ folder. Your team owns it, reviews it, and evolves it with the project.

Explore the harness contract →

my-app/
├── AGENT.md
└── .har/
    ├── README.md
    ├── stages.json
    ├── launch.sh
    ├── verify.sh
    ├── harness.env
    ├── logs/
    └── artifacts/

editable like any other code

02 / Isolation

Parallel work without collisions.

Each agent gets a dedicated worktree and environment slot.

main

slot-01agent A

slot-02agent B

slot-03agent C

03 / Verification

Proof, not “looks good.”

Normalized stages surface exactly what ran, how long it took, and what passed.

factory-lint5.3spassed

unit-tests25.7spassed

browser-e2e41.2spassed

One workflow, every agent

From “take this task” to a validated branch.

HAR normalizes the infrastructure around coding so the agent can focus on the code—and the reviewer can trust the result.

01 — Discover

The agent reads one stable interface.

Instead of guessing project-specific shell commands, the agent asks HAR what the repository can launch, verify, inspect, reset, and tear down.

$har env status --json

HAR MCPproject description

toolhar_describe_projectrepo: /workspace/my-app

{
  "profile": "default",
  "agentSlots": 4,
  "stages": [
    "launch", "verify", "test"
  ]
}

Mission Control

See the factory, not just the final diff.

A local dashboard for repositories, active slots, run history, verification stages, logs, and artifacts. The open-source control plane stays close to your machine and your code.