HAR 1.0: The open harness for AI coding workflows you can trust and verify HAR 1.0 has launched as an open-source agent harness, installable via `npm install -g @osfactory/har`, that gives each coding agent its own isolated worktree, ports and database, with a deterministic verify step that records logs, artifacts and a validated tree hash as evidence. HAR ships as a CLI and an MCP server, works with Claude Code, Cursor, Codex and any MCP agent, and includes Mission Control, an open-source local dashboard for tracking repositories, worktrees, runs, validations and artifacts. The project positions its machine-readable .har/ contract as an open standard stored in the repo itself, so verification setups stay portable across coding agents instead of being locked into one vendor's hosted sandbox. HAR is an open-source agent harness for AI coding workflows you can trust and verify. It runs every coding agent in its own isolated, consistent worktree , with deterministic validation, verifiable proof, and full observability. Run one agent or a whole fleet, with the same quality and control. It wraps the tools, tests, and CI you already use, and stays yours to customize. | | | ▶ Introduction demo , click the thumbnail to watch on YouTube | Works with Claude Code · Cursor · Codex · any MCP agent. - HAR. The core harness, available as both a CLI and an MCP server. It turns any repository into isolated worktrees with deterministic launch, verify, and teardown stages for coding agents to work in. - Mission Control. HAR's open-source local dashboard. It gives you one place to keep track of every repository, worktree, run, validation, and artifact across your projects. - Plugins. A growing ecosystem of open source plugins that further expand HAR's customizability and functionality. npm install -g @osfactory/har cd my-app har onboard scaffold .har/ and print a prompt for your coding agent har env launch 1 isolated worktree + running stack for agent slot 1 har env verify 1 --full run the project's real checks, record what passed Full walkthrough: Quickstart https://harproject.dev/docs/getting-started/quick-start/ . Running a coding agent is easy. Trusting what it produced, without re-checking every change by hand, is the hard part, and it only gets harder as tasks grow more complex and you run more agents at once. HAR was built to close those gaps: 1. No standard way to run or verify a repo. That knowledge is scattered across a README, a CLAUDE.md, Cursor rules, and CI yaml today, drifting out of sync with each other and the actual codebase. HAR replaces all of that with one machine-readable contract .har/ that Claude Code, Cursor, Codex, or any MCP agent reads the same way. 2. Multiple agents on one repo collide. Shared dev server, shared database, shared ports, conflicting git state. HAR gives each agent its own worktree, ports, and database per slot, so a fleet can genuinely run concurrently. 3. Trusting an agent's change means re-verifying it yourself. Every task runs the same deterministic verify step and leaves an evidence trail, logs, artifacts, a validated tree hash, so a reviewer can check proof of what ran instead of relying on the agent's self-report. 4. One platform's sandbox locks you in. If the contract lives inside a vendor's hosted dashboard, switching coding agents later means rebuilding the whole verification setup. HAR's contract is an open standard living in the repo itself, portable across whichever agent or tool you adopt. 5. Hand-rolled scripts rot as the stack changes. A new dependency, a new service, a new env var, and nobody updates the script until an agent's run fails for a confusing reason. har env maintain diffs your installed harness against current templates and flags drift before it causes a silent failure. HAR coordinates the work around the model, so agents can focus on the code and reviewers can trust the result. php flowchart LR D "Discover