VS Code Extension Marketplace

The VS Code Marketplace hosts 50,000+ extensions. Relevant to the vault because Cline, Continue, and Cursor are all VS Code extensions — understanding distribution helps when building MCP-integrated tooling or custom dev tools.

Extension Anatomy

my-extension/
├── package.json          # Manifest — declares id, activation, contributions
├── src/
│   └── extension.ts      # activate() + deactivate() entry points
├── .vscodeignore         # Files excluded from VSIX package
└── README.md             # Shown on the Marketplace listing page

package.json key fields

{
  "name": "my-extension",
  "displayName": "My Extension",
  "publisher": "your-publisher-id",
  "version": "1.0.0",
  "engines": { "vscode": "^1.85.0" },
  "categories": ["Other"],
  "activationEvents": ["onCommand:myext.helloWorld"],
  "main": "./out/extension.js",
  "contributes": {
    "commands": [
      { "command": "myext.helloWorld", "title": "Hello World" }
    ],
    "configuration": {
      "title": "My Extension",
      "properties": {
        "myext.apiKey": { "type": "string", "description": "API key" }
      }
    }
  }
}

Activation events: When VS Code loads your extension.

• onCommand: — activated when user runs the command
• onLanguage:python — activated when a Python file is opened
• * — activated at startup (avoid unless necessary; slows startup)

Contribution Points

Contribution points declare what an extension adds to VS Code's UI:

Packaging and Publishing

Install vsce (VS Code Extension CLI)

npm install -g @vscode/vsce

Package locally (VSIX)

vsce package
# Produces: my-extension-1.0.0.vsix

Install the VSIX locally for testing:

code --install-extension my-extension-1.0.0.vsix

Publish to Marketplace

One-time setup:

1. Create a publisher at https://marketplace.visualstudio.com/manage
2. Generate a Personal Access Token (PAT) in Azure DevOps with "Marketplace → Manage" scope
3. vsce login <publisher-id>

Publish:

vsce publish
# or publish a specific version bump:
vsce publish minor

GitHub Actions CI publishing

name: Publish Extension

on:
  push:
    tags: ["v*"]

jobs:
  publish:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci
      - run: npx vsce publish
        env:
          VSCE_PAT: ${{ secrets.VSCE_PAT }}

Store VSCE_PAT as a GitHub Actions secret. Trigger on version tags.

Open Source Extension Publishing (OVSX)

Open VSX Registry (https://open-vsx.org) is the open-source alternative used by VSCodium, Theia, Gitpod, and CodeServer. Publish to both registries to maximise reach:

npm install -g ovsx
ovsx publish my-extension-1.0.0.vsix -p $OVSX_TOKEN

Listing Quality

The Marketplace listing is built from README.md. Key elements:

• Animated GIF or screenshot in the first 500px
• Clear description of what the extension does
• Configuration section listing all settings
• Known issues or limitations
• Changelog link

Marketplace badge: Add to GitHub README:

[![VS Code Marketplace](https://img.shields.io/visual-studio-marketplace/v/publisher.extension)](https://marketplace.visualstudio.com/items?itemName=publisher.extension)

Key Facts

• package.json publisher field must match your Marketplace publisher ID
• VSIX is a ZIP archive — .vscodeignore keeps build artefacts out
• PAT scope must be "Marketplace → Manage" scoped to "All accessible organisations"
• Open VSX Registry (open-vsx.org) is the alternative for non-Microsoft editors
• vsce publish minor/major/patch bumps version automatically before publishing
• Activation event * delays VS Code startup — prefer specific activation events

Connections

• tools/github-marketplace-apps — GitHub Marketplace publishing; complementary distribution channel for developer tooling
• ai-tools/claude-code — Claude Code is a CLI, not a VS Code extension, but its MCP integration surfaces in Cursor/Continue which are extensions
• ai-tools/cline — open-source VS Code extension; published on both Marketplace and Open VSX
• ai-tools/continue — VS Code/JetBrains extension; uses the VS Code Extension API for context providers
• protocols/mcp — MCP servers can be bundled inside VS Code extensions (like Cline's tool integrations)

Open Questions

• Does the Marketplace enforce any content policy review for AI-powered extensions, or is it purely automated?
• What is the recommended approach for extensions that need to bundle Node.js binaries for different platforms?