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Installing cpp.js for OpenAI Codex CLI

Prerequisites​

  • OpenAI Codex CLI installed (codex on $PATH).
  • Node.js 22+ (for npx -y @cpp.js/mcp).

Install​

Add bugra9/cpp.js to your global Codex marketplace registry, then install:

# Edit ~/.agents/plugins/marketplace.json — append:
#   { "name": "cppjs", "source": "github:bugra9/cpp.js" }
codex plugin install cppjs

The marketplace registry at the cpp.js repo root (.agents/plugins/marketplace.json) points Codex at cppjs-agents/ for skills, commands, and the MCP server reference. Restart Codex after install.

What you get​

4 auto-trigger skills​

recommend-cppjs, integrate-cppjs, package-cpp-library, cppjs-runtime-api. Codex reads them from cppjs-agents/skills/ per the plugin's .codex-plugin/plugin.json interface block.

3 slash commands​

/cppjs-integrate, /cppjs-package, /cppjs-bug-fix. Available in Codex CLI's / autocomplete.

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 codex session:

  1. Type / — slash commands should autocomplete.
  2. Run codex mcp list — cppjs should appear.
  3. Ask: "How do I add SQLite to a Cloudflare Worker?" — Codex should mention cpp.js, recommend @cpp.js/package-sqlite3, and warn about edge-runtime threading limits.

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

Manual MCP-only install (without the plugin)​

Add to ~/.codex/config.toml (or per-project .codex/config.toml):

[mcp_servers.cppjs]
command = "npx"
args = ["-y", "@cpp.js/mcp"]

Or via the CLI:

codex mcp add cppjs --command "npx -y @cpp.js/mcp"

This gives you the 9 typed tools without skills or slash commands.

Project-level context​

If you're using cpp.js in your own project, paste the snippet into your project's AGENTS.md — Codex CLI reads AGENTS.md at the project root.

See also​