dev.code-extension_skill

Overview

This skill installs VS Code-compatible extensions from a local .vsix file into VS Code or Cursor (stable or nightly) via CLI. It targets code, code-insiders, cursor, and cursor-nightly binaries and provides the exact install and verification commands. Use it whenever you need a programmatic, reproducible local install of an extension. It also supports isolated installs for CI or scripts.

How this skill works

Provide a local filesystem path to a .vsix file and the skill returns the appropriate CLI commands to install that package into the chosen editor binary. It supports code, code-insiders, cursor, and cursor-nightly, including a macOS fallback path for Cursor Nightly. The skill also supplies verification commands to confirm installation and optional user-data/extensions directory flags for isolated installs.

When to use it

• You have a local .vsix file and need to install it into VS Code or Cursor programmatically.
• Automating extension installs in scripts, CI, or reproducible developer environments.
• Testing an extension build locally before publishing to the Marketplace.
• Installing an extension in a sandbox or isolated profile to avoid touching a developer profile.
• When asked explicitly to install an extension via CLI rather than using the Marketplace UI.

Best practices

• Always pass the full path to the .vsix file and use --force to overwrite existing installs if needed.
• Verify installation with --list-extensions --show-versions and grep for publisher.name or name.
• For CI or automation, use --user-data-dir and --extensions-dir to avoid modifying a personal profile.
• Prefer cursor-nightly on PATH; on macOS call the app bundle binary if the CLI is not available.
• In sandboxed environments, request elevated permissions because installs write to user/app support directories.

Example use cases

• Install a locally built extension into VS Code stable: code --install-extension "/path/to/ext.vsix" --force
• Add an extension to VS Code Insiders during a test run: code-insiders --install-extension "/path/to/ext.vsix" --force
• Install into Cursor Nightly on macOS using the app bundle path if cursor-nightly is not on PATH
• Run isolated installs in CI: cursor --user-data-dir /tmp/user --extensions-dir /tmp/ext --install-extension "/path/to/ext.vsix" --force
• Verify installation with: cursor --list-extensions --show-versions | rg -n "publisher.name|name"