---
title: "Scenario: multiple harnesses"
description: Several AI tools on one repository — same plugin per host, .cratis/ai.json as the one neutral record, per-host locks in their own settings.
---

Several AI coding tools working on the same repository. This page is the
multi-harness topic — per-harness getting started lives in the
[agent harness guide](/ai/harnesses/).

## What you do

1. Each person installs the plugin in their own harness exactly as the
   [harness guide](/ai/harnesses/) describes. Claude Code, Codex, Copilot,
   and Cursor each resolve the same canonical skill bytes, so two tools never
   see different guidance.
2. Pi (and any npm-consuming host) installs the published package with an
   exact pin recorded in `.pi/settings.json`:

   ```bash
   pi install -l npm:@cratis/ai-fundamentals@0.10.0
   ```

3. The repository commits `.cratis/ai.json` as the one neutral record of
   intended scope and version — harness-neutral by construction, because it
   names profiles (`cratis/chronicle/kotlin`), not host-specific things. The
   `harnesses` array inside it lists which hosts this repository expects the
   skills to reach.
4. Per-host locks stay in their own settings files (`.pi/settings.json`, your
   host's plugin list). No host reads another host's lock.

## What you get

- **One guidance corpus across every tool.** All marketplaces resolve the
  same `skills/` directory on the `Cratis/AI` default branch; adapters change
  packaging and discovery, never skill content.
- **One reviewed scope.** A pull request changes `.cratis/ai.json` once, and
  every harness's humans see the same diff.
- **No cross-contamination.** Skills are passive; no harness writes into
  another harness's configuration.

## When you don't need this

If everyone on the repository uses the same single harness, this page adds
nothing — the [team repository](/ai/scenarios/team-repository/) contract alone
is enough.

## Status

Per-host package availability differs today: marketplace hosts follow
`Cratis/AI` `main`; npm/Pi carries only the unsupported
`@cratis/ai-fundamentals` `0.x` evaluation; Kiro, Junie, and Gemini CLI are
pending (see the harness guide). The versioned flow that would pin every
harness to one reviewed release is designed but not published yet.