Loading skill
Install any skill in seconds. Free to start, no credit card required.
Get Started Free →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.
.claude/skills/sandbox-npm-install/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-09 | ✗→✓ | ▲ Improved | — | — |
| case-14 | ✗→✓ | ▲ Improved | — | — |
| case-18 | ✗→✓ | ▲ Improved | — | — |
| case-22 | ✗→✓ | ▲ Improved | — | — |
| case-21 | ✗→✓ | ▲ Improved | — | — |
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:
bashbash 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:
bashnpm 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.
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-09 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-14 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-18 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-22 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-21 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-02 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-10 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-19 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-08 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-01 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-17 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-13 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-03 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-20 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-15 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-04 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-11 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-05 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-07 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-12 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-16 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-06 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted, and 15 counted toward the lift figure. The other 7 produced results that are not comparable between the two arms, so they are excluded from the headline rather than averaged into it. The headline lift of +55 percentage points is the difference between those two pass rates over the 15 comparable cases. 1 case got worse with the skill loaded, and it is included in that figure.
The per-case answers from this run were removed by the retention sweep, so the case table below shows the verdicts without the text either arm produced. The counts above were recorded at the time and are unaffected. Answers are now kept for 180 days.
Other measured skills in the registry, with their headline benchmark lift.