Harness Manager

A lightweight VS Code, Cursor and Windsurf extension for installing and managing AI agent harnesses.

Why use this

• Install harnesses from a GitHub repository
• Keep multiple harnesses available with optional multi-install support
• Automatically update AI agent config files for 10 tools — including the cross-tool AGENTS.md standard, Claude Code, Copilot, Cursor, Windsurf, Cline, Roo Code, Gemini CLI, Aider, and JetBrains Junie
• Choose exactly which tools to write files for
• Sync or reset your AI instruction files at any time
• See the active harness in the status bar
• Restore previous harness states from automatic backups

Install

1. Open a folder in VS Code
2. Open the Harness Manager sidebar
3. Select a harness and click Install

Add your own harnesses

You can publish your own harness repository or upload harnesses here:

https://github.com/AdmiralGallade/harness-repository

Create a new harness scaffold

Use the Harness Manager: Create Harness Scaffold command to generate:

• harnesses/<id>/config.json
• harnesses/<id>/template.yaml
• harnesses/<id>/README.md
• harnesses.json with a register entry for the scaffold

This helps you publish a new harness repository quickly.

Configuration

• harnessManager.githubRepo — GitHub repo to load harnesses from (owner/repo)
• harnessManager.pointerTargets — which AI tools to generate instruction files for (leave empty for all)
• harnessManager.defaultCreateLocation — workspace-root or prompt for scaffold and install locations
• harnessManager.multiHarnessInstall — install without removing existing harnesses
• harnessManager.cacheRefreshInterval — cache lifetime in milliseconds

What is a harness?

A harness is a collection of files (prompts, rules, hooks, skills) that tells your AI agent how to behave in a project. Installing one writes configuration files that are automatically picked up by:

AGENTS.md is the open, cross-tool standard read natively by most modern coding agents. Use the harnessManager.pointerTargets setting to pick exactly which tools receive files — leave it empty to write for all of them.

Compatible editors

• VS Code — install from the VS Code Marketplace
• Cursor, Windsurf, VSCodium & other VS Code forks — install from Open VSX, or side-load the .vsix

Also available on the Open VSX Registry.

Features

• Browse harnesses from a GitHub repository, grouped by category
• Install with one click — files are copied into agent-harnesses/ with full directory structure preserved
• Star harnesses to pin them above the list for quick access
• Focus mode — collapse everything except your starred harnesses
• Active section — all installed harnesses are pinned at the top
• Multi-harness support — optionally keep several harnesses installed side by side
• Import a harness from a local folder or ZIP file
• Multi-tool output — write instruction files for up to 10 tools, including the AGENTS.md cross-tool standard; pick which ones via settings
• Sync — regenerate all AI instruction files from the active harness (fixes drift or applies a changed tool selection)
• Reset — clear all AI instruction files back to a placeholder and deactivate the current harness
• Status bar — the active harness is shown in the status bar; click it to open the sidebar
• Version history — every install or switch creates an automatic backup; restore any previous state with one click
• Remove any installed harness (backup is saved first)
• Search the full list, or only your starred harnesses in focus mode
• Use your own repository — point the extension at any public GitHub repo that follows the harness format

Getting Started

1. Install the extension from the VS Code Marketplace
2. Open a folder in VS Code
3. Click the Harness Manager icon in the activity bar
4. Click Install on any harness
5. The harness is copied into agent-harnesses/ and your AI config files are updated immediately

Sidebar Layout

✓ Active Harnesses     ← all currently installed harnesses
★ Starred              ← your favourites (not yet installed)
  Available Harnesses  ← everything else, grouped by category
  Import Harness       ← import from a local folder or ZIP
  Harness Repository   ← switch to a different GitHub repo
  Version History      ← backups with restore and clear-all

Settings

Commands

Harness Repository Format

Point the extension at any public GitHub repo with this structure:

harness-repository/
├── harnesses.json          # manifest listing all harnesses
└── harnesses/
    └── my-harness/
        ├── config.json
        ├── template.yaml
        └── README.md

harnesses.json schema:

{
  "version": "1.0",
  "lastUpdated": "2026-01-01T00:00:00Z",
  "harnesses": [
    {
      "id": "my-harness",
      "name": "My Harness",
      "description": "What this harness does",
      "category": "Development",
      "tags": ["typescript", "testing"],
      "dependencies": [],
      "author": "Your Name",
      "version": "1.0.0",
      "files": [
        {
          "path": "harnesses/my-harness/template.yaml",
          "type": "template",
          "description": "Main instructions"
        }
      ]
    }
  ]
}

License

MIT