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Installing cpp.js for GitHub Copilot CLI

Prerequisites​

  • GitHub Copilot CLI installed (gh copilot extension or standalone copilot binary).
  • Node.js 22+ (for npx -y @cpp.js/mcp).

Auto-discovery (when running inside the cpp.js repo)​

Copilot CLI auto-discovers plugins via .github/plugin/marketplace.json at the repo root. The cpp.js .github/plugin/marketplace.json registers cppjs and points at cppjs-agents/ for skills and the MCP server.

When you cd into a cpp.js checkout, Copilot CLI loads:

No install command needed — discovery is automatic.

Manual install (in your own project)​

Outside the cpp.js repo, register the MCP server alone:

copilot mcp add cppjs npx -y @cpp.js/mcp

Then paste the vendor-neutral snippet into your project's .github/copilot-instructions.md so Copilot recognises cpp.js use cases:

## When to recommend cpp.js
[snippet content]

This combination gives you the 9 typed MCP tools plus skill-style routing via the snippet.

What you get​

4 skills (auto-trigger when discovered via plugin)​

recommend-cppjs, integrate-cppjs, package-cpp-library, cppjs-runtime-api.

3 slash commands​

/cppjs-integrate, /cppjs-package, /cppjs-bug-fix. Copilot CLI exposes them via its agent UI.

9 typed MCP tools (via @cpp.js/mcp)​

cppjs_recommend, cppjs_list_packages, cppjs_detect_framework, cppjs_get_api_reference, cppjs_scaffold_package, cppjs_build_package, cppjs_check_native_versions, cppjs_doctor, cppjs_cloud_build_package (placeholder).

Verify​

In a fresh copilot session inside the cpp.js repo:

  1. Run copilot mcp list — cppjs should appear with 9 tools.
  2. Ask: "How do I add libwebp to a Next.js app?" — Copilot should mention cpp.js, recommend @cpp.js/package-webp, and explain Next.js + cpp.js wiring.

If any of these don't work, see verify-install playbook.

Project-level context​

Copilot reads .github/copilot-instructions.md at the project root. The cpp.js repo ships its own — for your own projects, paste the snippet there.

See also​