github/awesome-copilot/skills/sandbox-npm-install/SKILL.md
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.
Decision brief
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.
Compatibility matrix
| Platform | Status | Evidence | What to check |
|---|---|---|---|
| Codex | Not declared | No explicit evidence | Portability before use |
| Claude Code | Not declared | No explicit evidence | Portability before use |
| Cursor | Not declared | No explicit evidence | Portability before use |
| Gemini CLI | Not declared | No explicit evidence | Portability before use |
Installation
The source command is displayed only when detected. A safe inspection prompt is always available so your agent can explain every action before execution.
npx skills add https://github.com/github/awesome-copilot --skill "skills/sandbox-npm-install"Inspect the Agent Skill "sandbox-npm-install" from https://github.com/github/awesome-copilot/blob/9933dcad5be5caeb288cebcd370eeeb2fc2f1685/skills/sandbox-npm-install/SKILL.md at commit 9933dcad5be5caeb288cebcd370eeeb2fc2f1685. List every install step, command, network request, credential, file read/write, external action, and rollback step. Explain whether it fits my task. Do not install or execute anything until I approve.
Workflow
Run the bundled install script from the workspace root:
After the script completes, verify your toolchain works. For example:
Use this skill whenever: - You need to install npm packages for the first time in a new sandbox session - package.json or package-lock.json has changed and you need to reinstall - You encounter native binary crashes with errors like SIGILL, SIGSEGV, mmap, or unaligned sysNoHugeP…
A Docker sandbox environment with a virtiofs-mounted workspace
Permission review
The documentation asks the agent to run terminal commands or scripts.
Run the bundled install script from the workspace root:The documentation asks the agent to run terminal commands or scripts.
bash scripts/install.shEvidence record
| Signal | Value | Evidence type | Meaning |
|---|---|---|---|
| Quality score | 83/100 | Computed | Documentation, specificity, maintenance, and trust rules |
| Repository stars | 37,126 | Source | Repository attention, not individual Skill quality |
| Compatibility | 0 platforms | Source | Declared in the catalog source record |
| Usage guide | automated source guide | Editorial | Generated or reviewed according to the visible evidence level |
Pinned source
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:
bash scripts/install.sh
| 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:
npm test # Run project tests
npm run build # Build the project
npm run dev # Start dev server
/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.