Make marketplace and plugins discoverable by both GitHub Copilot CLI and Claude Code

[Copilot]

Plugins were only discoverable by Copilot CLI (via .github/plugin/). Both Copilot CLI and Claude Code share support for .claude-plugin/ as a canonical plugin directory, so consolidating there eliminates duplication while enabling both tools.

Changes

• Manifest locations — renamed .github/plugin/marketplace.json → .claude-plugin/marketplace.json and plugins/linting/.github/plugin/plugin.json → plugins/linting/.claude-plugin/plugin.json
• Marketplace format — added $schema (Claude Code) and top-level description (Claude Code) alongside the existing metadata.version (Copilot CLI)
• README — split installation into Copilot CLI / Claude Code subsections with per-tool commands; added Sharing with contributors section documenting .claude/settings.json for project-level plugin recommendations in Claude Code (Copilot CLI has no equivalent mechanism)
• AGENTS.md — updated path references and description to reflect dual-tool compatibility
• Versions — linting 0.2.3 → 0.2.4, marketplace 0.4.2 → 0.4.3

Sharing with contributors (Claude Code)

Commit a .claude/settings.json to any repo to recommend plugins to contributors. When contributors trust the project folder in Claude Code, they are prompted to install the marketplace and any enabled plugins automatically — no prior marketplace registration required:

{
  "extraKnownMarketplaces": {
    "heaths-plugins": {
      "source": {
        "source": "github",
        "repo": "heaths/plugins"
      }
    }
  },
  "enabledPlugins": {
    "linting@heaths-plugins": true
  }
}

Original prompt

Using https://code.claude.com/docs/en/plugins and https://docs.github.com/en/copilot/how-tos/copilot-cli/customize-copilot/plugins-creating, update plugins and the marketplace in this repo so that they are discoverable and installable by both copilot cli and Claude code with little to no duplication. Since copilot seems to support Claude code directories, that probably means just using those. Update documentation appropriately. Also update the readme with how to add the marketplace and/or plugins to another repo to share with other contributors in that repo - almost like recommended extensions. Claude code seems to support this but not sure about copilot. Try to figure out and update the readme accordingly. It autos be a new section below how to install the plugins.

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[heaths]

This would require the marketplace to always be installed. Try to fetch documentation again (I allowed those URLs). The individual plugins with source locations probably need to be in settings.

[Copilot]

Fixed in d215272. The example now uses extraKnownMarketplaces to register the marketplace source directly (no prior marketplace install needed) and enabledPlugins to opt into specific plugins. Claude Code prompts contributors to install both when they trust the project folder.

[heaths]

LGTM but I want to test this out first.