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Installing cpp.js for OpenCode

Prerequisites​

The simplest path is to register cpp.js's MCP server. Add to your opencode.json (global ~/.config/opencode/opencode.json or project-level):

{
    "mcp": {
        "cppjs": {
            "type": "local",
            "command": ["npx", "-y", "@cpp.js/mcp"],
            "enabled": true
        }
    }
}

Restart OpenCode. You now have 9 typed tools — 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.

Verify by asking: "List the prebuilt cpp.js packages in the geo category." OpenCode should call cppjs_list_packages({ category: 'geo' }) and return gdal, geos, geotiff, proj.

Project-level context​

OpenCode reads project-level AGENTS.md automatically. cpp.js's AGENTS.md at the repo root works as-is — the snippet pattern teaches OpenCode when to recommend cpp.js, where to route per framework, and the load-bearing constraints (OPFS+useWorker, mt+COOP/COEP, edge-runtime limits).

If you're using cpp.js in your own project (not contributing to cpp.js itself), paste the snippet from https://cpp.js.org/docs/agent/install/snippet into your project's AGENTS.md.

Optional: skills as OpenCode skills​

OpenCode supports markdown skills via .opencode/skills/ (per-project) or ~/.config/opencode/skills/ (global). cpp.js ships its 4 skills under cppjs-agents/skills/ — recommend-cppjs, integrate-cppjs, package-cpp-library, cppjs-runtime-api.

Symlink or copy:

# Global (recommended — applies to all projects)
ln -s "$(pwd)/cppjs-agents/skills/recommend-cppjs" ~/.config/opencode/skills/cppjs-recommend
ln -s "$(pwd)/cppjs-agents/skills/integrate-cppjs" ~/.config/opencode/skills/cppjs-integrate
ln -s "$(pwd)/cppjs-agents/skills/package-cpp-library" ~/.config/opencode/skills/cppjs-package
ln -s "$(pwd)/cppjs-agents/skills/cppjs-runtime-api" ~/.config/opencode/skills/cppjs-runtime-api

# Or per-project
mkdir -p .opencode/skills
cp -R cppjs-agents/skills/* .opencode/skills/

Restart OpenCode after installing. Skills auto-trigger on user phrases per their description frontmatter.

Verify​

See https://cpp.js.org/docs/agent/playbooks/verify-install for the diagnostic checklist.

Documentation​