| name | setup-review-sandbox |
| description | One-time setup of the sandbox prerequisites used by the reproduce-issue skill and the reproduce-verifier agent — Docker, the isolation runtime (gVisor on Linux / Colima on macOS), healthy container networking, and the nx-review-sandbox toolchain image (built from the repo's mise.toml). Idempotent; re-run any time to verify or repair. Use when the user says "set up the review sandbox", "install the sandbox prereqs", "build the sandbox image", or a reproduce-issue preflight reports something MISSING. |
| allowed-tools | Read, Grep, Glob, Bash(uname *), Bash(docker info *), Bash(docker run *), Bash(docker build *), Bash(docker image inspect *), Bash(docker images *), Bash(command -v *), Bash(lsmod *), Bash(bash tools/review-sandbox/*) |
Set up the review sandbox (one-time)
Installs and verifies everything the reproduce-issue skill / reproduce-verifier agent need to run untrusted PR code in isolation. Idempotent — each step checks first and only acts if needed. Steps needing sudo are handed to the user to run in their terminal (this skill cannot sudo non-interactively).
Run uname -s first — the path differs on Linux vs macOS.
1. Docker
docker info >/dev/null 2>&1 && echo "docker OK" || echo "docker MISSING"
- MISSING, Linux: install Docker Engine, then
sudo systemctl enable --now docker and add yourself to the docker group (sudo usermod -aG docker $USER, then re-login).
- MISSING, macOS:
brew install colima docker then colima start (or install Docker Desktop).
2. Isolation runtime
Linux — gVisor (runsc)
docker info --format '{{range $k,$v := .Runtimes}}{{$k}} {{end}}' | grep -q runsc && echo "runsc OK" || echo "runsc MISSING"
If MISSING, have the user run this in their terminal (needs sudo; their shell is fish — exit codes are $status):
sudo apt-get update && sudo apt-get install -y apt-transport-https ca-certificates curl gnupg
curl -fsSL https://gvisor.dev/archive.key | sudo gpg --dearmor -o /usr/share/keyrings/gvisor-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/gvisor-archive-keyring.gpg] https://storage.googleapis.com/gvisor/releases release main" | sudo tee /etc/apt/sources.list.d/gvisor.list
sudo apt-get update && sudo apt-get install -y runsc
sudo runsc install
sudo systemctl restart docker
Then re-check the runtime line above.
macOS — the Docker VM is the sandbox
No runsc. Just confirm the VM is up:
docker info >/dev/null 2>&1 && echo "docker VM OK" || echo "start it: colima start"
3. Container networking (catches the veth class of breakage)
docker run --rm --network none alpine true && echo "sandbox OK"
docker run --rm alpine true && echo "networking OK" || echo "networking BROKEN"
If the first passes but the second fails with veth ... operation not supported:
sudo modprobe veth
If modprobe errors with a BTF / version mismatch (failed to validate module [veth] BTF), the running kernel no longer matches its on-disk modules (a kernel update landed while it was booted) — reboot, after which it auto-loads. Persist it: echo veth | sudo tee /etc/modules-load.d/veth.conf.
4. The toolchain image (nx-review-sandbox)
Needed only to build an unreleased PR's nx in the sandbox (reproduce-verifier Level 2). Reproducing against a published nx version does NOT need it.
Build it — unconditionally, without first checking whether it exists:
bash tools/review-sandbox/build-image.sh
Don't gate this on an existence check. An image built from any older revision passes one identically, so a missing capability stays invisible until a review is mysteriously slow — which is exactly how an image predating the pnpm-store warming went unnoticed for two weeks, costing ~25 minutes of package downloads on every review in between. Docker's layer cache already answers the question properly: ~0.6 s when nothing changed, a real rebuild when something did. review-pr calls the same script in its own pre-flight for that reason, so the image is kept current by every review rather than by remembering to re-run this skill.
The script builds from a minimal context — five entries, ~2 MB, almost all of it the lockfile — and never . (the repo root), which would ship the whole monorepo (node_modules / .git / dist — many GB) to the daemon. All five entries are load-bearing; the Dockerfile explains what each omission breaks.
This installs the repo's exact toolchain — node/java/dotnet/maven/rust/bun via mise — and warms the pnpm store so reviews link packages instead of downloading them. Takes a while and several GB (the warm store is ~2.6 GB of that). Requires steps 1 + 3 to pass first (build needs working networking). If disk is tight, /sandbox-prune first.
5. Verify (smoke test)
Confirm the sandbox actually isolates and carries the tools:
docker run --rm $RUNTIME nx-review-sandbox:latest bash -c '
cd /work # mise resolves versions from the mise.toml here; do NOT use bash -l (a login shell resets PATH, dropping the mise dirs)
echo "kernel: $(uname -r)" # Linux+gVisor: 4.19.0-gvisor ; macOS: the VM kernel
mise ls | head
node --version; java --version 2>&1 | head -1; dotnet --version
'
Green when: the kernel is NOT your host kernel, and node/java/dotnet report versions. Report a concise ✅/❌ per step and what (if anything) the user still needs to run.
