npx skills add ...
npx skills add github/awesome-copilot --skill sandbox-npm-install
npx skills add github/awesome-copilot --skill sandbox-npm-install
Install npm packages in a Docker sandbox environment. Use this skill whenever you need to install, reinstall, or update node_modules inside a container where the workspace is mounted via virtiofs. Native binaries (esbuild, lightningcss, rollup) crash on virtiofs, so packages must be installed on the local ext4 filesystem and symlinked back.
Use this skill whenever:
package.json or package-lock.json has changed and you need to reinstallSIGILL, SIGSEGV, mmap, or unaligned sysNoHugePageOSnode_modules directory is missing or corruptedpackage.json file in the target workspaceDocker sandbox workspaces are typically mounted via virtiofs (file sync between the host and Linux VM). Native Go and Rust binaries (esbuild, lightningcss, rollup, etc.) crash with mmap alignment failures when executed from virtiofs on aarch64. The fix is to install on the container's local ext4 filesystem and symlink back into the workspace.
Run the bundled install script from the workspace root:
| Option | Description |
|---|---|
--workspace <path> | Path to directory containing package.json (auto-detected if omitted) |
--playwright | Also install Playwright Chromium browser for E2E testing |
package.json, package-lock.json, and .npmrc (if present) to a local ext4 directorynpm ci (or npm install if no lockfile) on the local filesystemnode_modules back into the workspacesudo when available)If verification fails, run the script again — crashes can be intermittent during initial setup.
After the script completes, verify your toolchain works. For example:
/home/agent/project-deps) is container-local and is NOT synced back to the hostnode_modules symlink appears as a broken link on the host — this is harmless since node_modules is typically gitignorednpm ci or npm install on the host naturally replaces the symlink with a real directorypackage.json or package-lock.json change, re-run the install scriptnpm ci or npm install directly in the mounted workspace — native binaries will crash| Problem | Solution |
|---|---|
SIGILL or SIGSEGV when running dev server | Re-run the install script; ensure you're not running npm install directly in the workspace |
node_modules not found after install | Check that the symlink exists: ls -la node_modules |
| Permission errors during install | Ensure the local deps directory is writable by the current user |
| Verification fails intermittently | Run the script again — native binary crashes can be non-deterministic on first load |
If your project uses Vite, you may need to allow the symlinked path in server.fs.allow. Add the symlink target's parent directory (e.g., /home/agent/project-deps/) to your Vite config so that Vite can serve files through the symlink.