
Sandbox Npm Install
- 1.6k installs
- 37.1k repo stars
- Updated July 28, 2026
- github/awesome-copilot
sandbox-npm-install installs npm dependencies in Docker virtiofs sandboxes via ext4 install and workspace symlinks.
About
The sandbox-npm-install skill fixes native binary crashes when installing npm packages in Docker sandboxes with virtiofs-mounted workspaces. Tools like esbuild, lightningcss, and rollup fail with SIGILL or mmap errors on aarch64 virtiofs, so the bundled install script copies package manifests to a container-local ext4 path, runs npm ci or install there, and symlinks node_modules into the workspace. It supports Playwright browser install, verifies known native binaries, and documents post-install test and build checks. Agents re-run after package.json or lockfile changes and must not run npm install directly on the mounted workspace. Troubleshooting covers permission errors, broken host symlinks, and intermittent verification failures. Use on first sandbox session setup, lockfile updates, or when dev servers crash with native module errors.
- Installs node_modules on local ext4 to avoid virtiofs native binary crashes.
- Bundles scripts/install.sh with npm ci, symlink, and binary verification.
- Supports optional Playwright Chromium install for E2E sandboxes.
- Documents re-run triggers after package.json or lockfile changes.
- Warns against direct npm install on virtiofs-mounted workspaces.
Sandbox Npm Install by the numbers
- 1,626 all-time installs (skills.sh)
- +21 installs in the week ending Jul 28, 2026 (Skillselion tracking)
- Ranked #126 of 1,453 DevOps & CI/CD skills by installs in the Skillselion catalog
- Security screen: MEDIUM risk (skills.sh audit)
- Data as of Jul 28, 2026 (Skillselion catalog sync)
sandbox-npm-install capabilities & compatibility
- Capabilities
- ext4 npm install · node_modules symlink · native binary verification
- Use cases
- devops · ci cd
npx skills add https://github.com/github/awesome-copilot --skill sandbox-npm-installAdd your badge
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| Installs | 1.6k |
|---|---|
| repo stars | ★ 37.1k |
| Security audit | 2 / 3 scanners passed |
| Last updated | July 28, 2026 |
| Repository | github/awesome-copilot ↗ |
Why do esbuild or vite crash with SIGILL after npm install in a sandbox?
Install npm packages in Docker virtiofs sandboxes by running deps on local ext4 and symlinking node_modules back to the workspace.
Who is it for?
Copilot sandbox sessions on virtiofs with Node native dependencies.
Skip if: Host-native installs without Docker virtiofs constraints.
When should I use this skill?
User hits native binary crashes, missing node_modules, or lockfile changes in sandbox.
What you get
Working node_modules symlink with verified native binaries ready for test and dev commands.
- symlinked node_modules directory
- installed npm dependencies on ext4
By the numbers
- Defaults node_modules install base to /home/agent/project-deps on local ext4
- Targets native binary crashes from esbuild, lightningcss, and rollup on virtiofs
Files
Sandbox npm Install
When to Use This Skill
Use this skill whenever:
- You need to install npm packages for the first time in a new sandbox session
package.jsonorpackage-lock.jsonhas changed and you need to reinstall- You encounter native binary crashes with errors like
SIGILL,SIGSEGV,mmap, orunaligned sysNoHugePageOS - The
node_modulesdirectory is missing or corrupted
Prerequisites
- A Docker sandbox environment with a virtiofs-mounted workspace
- Node.js and npm available in the container
- A
package.jsonfile in the target workspace
Background
Docker 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.
Step-by-Step Installation
Run the bundled install script from the workspace root:
bash scripts/install.shCommon Options
| Option | Description |
|---|---|
--workspace <path> | Path to directory containing package.json (auto-detected if omitted) |
--playwright | Also install Playwright Chromium browser for E2E testing |
What the Script Does
1. Copies package.json, package-lock.json, and .npmrc (if present) to a local ext4 directory 2. Runs npm ci (or npm install if no lockfile) on the local filesystem 3. Symlinks node_modules back into the workspace 4. Verifies known native binaries (esbuild, rollup, lightningcss, vite) if present 5. Optionally installs Playwright browsers and system dependencies (uses sudo when available)
If verification fails, run the script again — crashes can be intermittent during initial setup.
Post-Install Verification
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 serverImportant Notes
- The local install directory (e.g.,
/home/agent/project-deps) is container-local and is NOT synced back to the host - The
node_modulessymlink appears as a broken link on the host — this is harmless sincenode_modulesis typically gitignored - Running
npm ciornpm installon the host naturally replaces the symlink with a real directory - After any
package.jsonorpackage-lock.jsonchange, re-run the install script - Do NOT run
npm ciornpm installdirectly in the mounted workspace — native binaries will crash
Troubleshooting
| 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 |
Vite Compatibility
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.
#!/usr/bin/env bash
set -euo pipefail
# Sandbox npm Install Script
# Installs node_modules on local ext4 filesystem and symlinks into the workspace.
# This avoids native binary crashes (esbuild, lightningcss, rollup) on virtiofs.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
# Local ext4 base directory where node_modules is installed to avoid virtiofs crashes.
# Change this path if your sandbox uses a different local filesystem location.
readonly DEPS_BASE="/home/agent/project-deps"
WORKSPACE_CLIENT=""
INSTALL_PLAYWRIGHT="false"
usage() {
cat <<EOF
Usage: $(basename "$0") [options]
Options:
--workspace <path> Client workspace containing package.json
--playwright Install Playwright Chromium browser
--help Show this help message
Examples:
bash scripts/install.sh
bash scripts/install.sh --workspace app/client --playwright
EOF
}
while [[ $# -gt 0 ]]; do
case "$1" in
--workspace)
if [[ -z "${2:-}" ]]; then
echo "Error: --workspace requires a path argument"
usage
exit 1
fi
WORKSPACE_CLIENT="$2"
shift 2
;;
--playwright)
INSTALL_PLAYWRIGHT="true"
shift
;;
--help|-h)
usage
exit 0
;;
*)
echo "Unknown option: $1"
usage
exit 1
;;
esac
done
if [[ -z "$WORKSPACE_CLIENT" ]]; then
if [[ -f "$PWD/package.json" ]]; then
WORKSPACE_CLIENT="$PWD"
elif [[ -f "$REPO_ROOT/package.json" ]]; then
WORKSPACE_CLIENT="$REPO_ROOT"
fi
fi
if [[ -n "$WORKSPACE_CLIENT" ]]; then
WORKSPACE_CLIENT="$(cd "$WORKSPACE_CLIENT" 2>/dev/null && pwd || true)"
fi
if [[ -z "$WORKSPACE_CLIENT" || ! -f "$WORKSPACE_CLIENT/package.json" ]]; then
echo "Could not find a valid workspace client path containing package.json."
echo "Use --workspace <path> to specify it explicitly."
exit 1
fi
echo "=== Sandbox npm Install ==="
echo "Workspace: $WORKSPACE_CLIENT"
# Derive a unique subdirectory from the workspace path relative to the repo root.
# e.g. /repo/apps/web -> apps-web, /repo -> <repo-basename>
REL_PATH="${WORKSPACE_CLIENT#"$REPO_ROOT"}"
REL_PATH="${REL_PATH#/}"
if [[ -z "$REL_PATH" ]]; then
REL_PATH="$(basename "$REPO_ROOT")"
fi
# Sanitize: replace path separators with hyphens
DEPS_SUBDIR="${REL_PATH//\//-}"
DEPS_DIR="${DEPS_BASE}/${DEPS_SUBDIR}"
echo "Deps dir: $DEPS_DIR"
# Step 1: Prepare local deps directory
echo "→ Preparing $DEPS_DIR..."
if [[ -z "$DEPS_DIR" || "$DEPS_DIR" != "${DEPS_BASE}/"* ]]; then
echo "ERROR: DEPS_DIR ('$DEPS_DIR') is not under DEPS_BASE ('$DEPS_BASE'). Aborting."
exit 1
fi
rm -rf "$DEPS_DIR"
mkdir -p "$DEPS_DIR"
chmod 700 "$DEPS_DIR"
cp "$WORKSPACE_CLIENT/package.json" "$DEPS_DIR/"
# Copy .npmrc if present (needed for private registries / scoped packages)
# Permissions restricted to owner-only since .npmrc may contain auth tokens
if [[ -f "$WORKSPACE_CLIENT/.npmrc" ]]; then
cp "$WORKSPACE_CLIENT/.npmrc" "$DEPS_DIR/"
chmod 600 "$DEPS_DIR/.npmrc"
fi
if [[ -f "$WORKSPACE_CLIENT/package-lock.json" ]]; then
cp "$WORKSPACE_CLIENT/package-lock.json" "$DEPS_DIR/"
INSTALL_CMD=(npm ci)
else
echo "! package-lock.json not found; falling back to npm install"
INSTALL_CMD=(npm install)
fi
# Step 2: Install on local ext4
echo "→ Running ${INSTALL_CMD[*]} on local ext4..."
cd "$DEPS_DIR" && "${INSTALL_CMD[@]}"
# Step 3: Symlink into workspace
echo "→ Symlinking node_modules into workspace..."
cd "$WORKSPACE_CLIENT"
rm -rf node_modules
ln -s "$DEPS_DIR/node_modules" node_modules
has_dep() {
local dep="$1"
node -e "
const pkg=require(process.argv[1]);
const deps={...(pkg.dependencies||{}),...(pkg.devDependencies||{}),...(pkg.optionalDependencies||{})};
process.exit(deps[process.argv[2]] ? 0 : 1);
" "$WORKSPACE_CLIENT/package.json" "$dep"
}
verify_one() {
local label="$1"
shift
if "$@" >/dev/null 2>&1; then
echo " ✓ $label OK"
return 0
fi
echo " ✗ $label FAIL"
return 1
}
# Step 4: Verify native binaries when present in this project
echo "→ Verifying native binaries..."
FAIL=0
if has_dep esbuild; then
verify_one "esbuild" node -e "require('esbuild').transform('const x: number = 1',{loader:'ts'}).catch(()=>process.exit(1))" || FAIL=1
fi
if has_dep rollup; then
verify_one "rollup" node -e "import('rollup').catch(()=>process.exit(1))" || FAIL=1
fi
if has_dep lightningcss; then
verify_one "lightningcss" node -e "try{require('lightningcss')}catch(_){process.exit(1)}" || FAIL=1
fi
if has_dep vite; then
verify_one "vite" node -e "import('vite').catch(()=>process.exit(1))" || FAIL=1
fi
if [ "$FAIL" -ne 0 ]; then
echo "✗ Binary verification failed. Try running the script again (crashes can be intermittent)."
exit 1
fi
# Step 5: Optionally install Playwright
if [[ "$INSTALL_PLAYWRIGHT" == "true" ]]; then
echo "→ Installing Playwright browsers..."
if [[ "${EUID:-$(id -u)}" -eq 0 ]]; then
npx playwright install --with-deps chromium
elif command -v sudo &>/dev/null && sudo -n true 2>/dev/null; then
# Non-root but passwordless sudo available — install browsers then system deps
npx playwright install chromium
sudo npx playwright install-deps chromium
else
npx playwright install chromium
echo "⚠ System dependencies not installed (no root/sudo access)."
echo " Playwright tests may fail. Run: sudo npx playwright install-deps chromium"
fi
fi
echo ""
echo "=== ✓ Sandbox npm install complete ==="
echo "Run 'npm run dev' to start the dev server."
Related skills
How it compares
Use Sandbox npm Install instead of standard npm install when the workspace is virtiofs-mounted in an agent sandbox and native addon binaries crash.
FAQ
Why not run npm ci in the workspace?
Native Go and Rust binaries crash when executed from virtiofs on aarch64 sandboxes.
Will node_modules sync to the host?
The symlink may look broken on the host but is harmless because node_modules is gitignored.
When should I re-run the install script?
After any package.json or package-lock.json change or corrupted node_modules.
Is Sandbox Npm Install safe to install?
skills.sh reports 2 of 3 security scanners passed. Review the Security Audits panel on this page before installing in production.