New: 97,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Linux Vm Test

by nubjs in nubjs/nub

Run ad-hoc Nub tests and debugging probes on real local Linux guests.

MITAuto-check passedDevelopment

Install Linux Vm Test

skills CLI
$ npx skills add nubjs/nub --skill linux-vm-test -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install nubjs/nub linux-vm-test --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/nubjs/nub.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/linux-vm-test .claude/skills/linux-vm-test && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
linux-vm-test
GitHub stars
4.4k
Token cost
~986 tokens
SKILL.md length
329 words
Files
2
Skills in repo
31
Repo updated
First seen
Licence
MIT

At a glance

Run ad-hoc Nub tests and debugging probes on real local Linux guests.

  • Linux-specific sandbox
  • SKILL.md covers Preflight, Persistent Lima debugging, Clean Tart reproduction and Evidence
  • Calls cargo and rsync
  • Runtime behavior that Docker cannot reproduce faithfully

What it does

Linux Vm Test is an agent skill from nubjs/nub. Run ad-hoc Nub tests and debugging probes on real local Linux guests. Use for Linux-specific sandbox, kernel, distro, architecture, package, or runtime behavior that Docker cannot reproduce faithfully. Selects persistent Lima for source-mounted iteration or ephemeral Tart for clean-image reproduction.

Its SKILL.md is about 990 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files (for example `agents/openai.yaml`).

It sits in Development, covering Containers and Debugging. It works with Linux and Docker. The repository describes itself as: The fast all-in-one Node.js toolkit. The licence is MIT.

When your agent uses it

  • Linux-specific sandbox
  • Runtime behavior that Docker cannot reproduce faithfully

Example prompts

  • “/linux-vm-test”

Requirements

  • Docker

What it can do on your machine

Read from SKILL.md and the folder at commit 568e73a. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • cargo
    • rsync

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md. Its commands use rsync, which can reach the network depending on how they are called.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Linux Vm Test loads about 986 tokens when it runs. Until then it costs about 79 tokens; SKILL.md has 329 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~79
When it runs · the whole SKILL.md, loaded when a task matches
~986

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from nubjs/nub at commit 568e73a, republished under its MIT licence (© nubjs). 329 words, ~986 tokens.

Download SKILL.mdSave it as .claude/skills/linux-vm-test/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
linux-vm-test
description
Run ad-hoc Nub tests and debugging probes on real local Linux guests. Use for Linux-specific sandbox, kernel, distro, architecture, package, or runtime behavior that Docker cannot reproduce faithfully. Selects persistent Lima for source-mounted iteration or ephemeral Tart for clean-image reproduction.
metadata.internal
true

Linux VM testing

Use a real VM only when the behavior depends on a Linux kernel or guest OS. Prefer Docker for userspace-only clean-cache/config experiments and ci-adhoc-test for unavailable architectures, distributions, or release-platform proof.

Two local backends serve different purposes:

  • Lima landlock-vm: persistent Ubuntu arm64 debugger with the host home mounted read-only.
  • Tart: disposable Ubuntu arm64 guest for clean-machine or alternate-image reproduction.

Preflight

Inspect both backends before changing VM state:

sh
limactl list
tart list
limactl shell landlock-vm -- bash -lc \
  'uname -srm; . /etc/os-release; echo "$PRETTY_NAME"; df -h "$HOME" /tmp'

Confirm the source mount before treating it as writable:

sh
limactl shell landlock-vm -- bash -lc \
  'findmnt -T /Users/colinmcd94/Documents/projects/nub'

The known Lima mount is read-only. Never build in /Users/colinmcd94/**. If the guest disk is full, report it and ask before reclaiming space. Never stop, delete, or clean an existing VM merely to make room.

Persistent Lima debugging

Run a short probe synchronously against the exact host source state:

sh
limactl shell landlock-vm -- bash -lc \
  'cd /Users/colinmcd94/.cache/nub/worktrees/<worktree> && <probe>'

Trace a guest command without modifying the host checkout:

sh
limactl shell landlock-vm -- bash -lc \
  'strace -f -o /tmp/nub.strace -- <command>'
limactl shell landlock-vm -- bash -lc \
  'bpftrace -l "tracepoint:syscalls:sys_enter_*" | head'

For a Linux Rust build, copy the exact source state into guest-local storage and use a guest-only target directory:

sh
limactl shell landlock-vm -- bash -lc '
  mkdir -p "$HOME/src" "$HOME/.cache/nub/linux-vm-target"
  src=/Users/colinmcd94/.cache/nub/worktrees/<worktree>
  dest="$HOME/src/nub-<slug>"
  rsync -a --delete \
    --exclude .git --exclude target --exclude node_modules \
    "$src/" "$dest/"
  cd "$dest"
  export CARGO_TARGET_DIR="$HOME/.cache/nub/linux-vm-target/<slug>"
  cargo build -p nub-cli --profile fast
  cargo test -p nub-cli --test <test_stem>
'

Repeat the copy after host edits. Use the exact host worktree under test, a distinct guest target for each branch or probe, and direct Cargo commands because the copied tree intentionally omits Git metadata. Remove only probe-owned files after capturing evidence; do not sweep guest caches or unrelated targets.

Start or stop the persistent VM only when required:

sh
limactl start landlock-vm
limactl stop landlock-vm

Clean Tart reproduction

Let the checked-in helper own lifecycle:

sh
tests/vm/tart-vm.sh up <name> <image>
tests/vm/tart-vm.sh exec <name> -- bash -lc '<probe>'
tests/vm/tart-vm.sh run <name> ./probe.sh
tests/vm/tart-vm.sh down <name>
tests/vm/tart-vm.sh rm <name>

Use a unique VM name. The run operation copies one script when sshpass is installed and otherwise streams its body; it does not copy a fixture tree or checkout. Fetch or copy multi-file fixtures deliberately. Finish a throwaway run with rm; down intentionally preserves the disk.

Evidence

Record:

  • Host commit plus dirty-state summary.
  • Guest distro, kernel, and architecture.
  • Exact command and environment overrides.
  • Exit status, stdout, and stderr.
  • Relevant trace or log path.

Copy concise results to the host before deleting a Tart guest. Do not claim x86_64 coverage from these Apple-Silicon arm64 VMs. Use ci-adhoc-test when the claim requires x86_64-native behavior or another unavailable platform.

© nubjs, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file in .claude/skills/linux-vm-test of nubjs/nub.

  • SKILL.md
  • agents/openai.yaml

Open the folder on GitHubat commit 568e73a

Compare with similar skills

Linux Vm Test next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Linux Vm Test compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Linux Vm Test this skillnubjs/nub4.4k—~986Automated safety check: PassMIT
Dotnet Debuggingnovotnyllc/dotnet-artisan233—~2.1kAutomated safety check: PassMIT
.NET Crash Dump Collectiondotnet/skills5.6k2 repos~1.1kAutomated safety check: PassMIT
Linux Troubleshooting with Inspektor Gadgetinspektor-gadget/inspektor-gadget2.9k—~2.4kAutomated safety check: NotesApache-2.0
Debug CIweb-infra-dev/rslint460—~2.8kAutomated safety check: PassMIT
Localnetboundless-xyz/boundless193—~1.8kAutomated safety check: NotesApache-2.0

Similar skills

  • Dotnet Debugging

    novotnyllc/dotnet-artisan

    Debugs Windows and Linux/macOS applications (native, .NET/CLR, mixed-mode) with WinDbg MCP (crash dumps, !analyze, !syncblk, !dlk, !runaway, !dumpheap, !gcroot, BSOD), dotnet-dump, lldb with SOS…

    233 GitHub stars~2.1k tokensUpdated 1 mo ago
    DevelopmentAuto-check passed

  • .NET Crash Dump Collection

    dotnet/skills

    Official

    Configures automatic crash dumps or captures dumps from running processes for modern .NET apps on Linux, macOS and Windows, including Docker and Kubernetes.

    5.6k GitHub starsUsed in 2 repos~1.1k tokens
    DevOps & CloudAuto-check passed

  • Linux Troubleshooting with Inspektor Gadget

    inspektor-gadget/inspektor-gadget

    Debugs a single Linux host or container runtime at the kernel level with the standalone ig binary and eBPF gadgets, read-only and without Kubernetes.

    2.9k GitHub stars~2.4k tokensUpdated today
    DevOps & CloudAuto-check: notes

  • Debug CI

    web-infra-dev/rslint

    Reproduce Linux CI failures locally using Docker when the same tests pass on the host, especially Go platform differences and VS Code extension tests requiring xvfb.

    460 GitHub stars~2.8k tokensUpdated today
    DevelopmentAuto-check passed

  • Localnet

    boundless-xyz/boundless

    Start and interact with the Boundless localnet (docker compose-based local development network).

    193 GitHub stars~1.8k tokensUpdated 1 mo ago
    DevelopmentAuto-check: notes

  • Debugging Local Task Agent Runs

    PostHog/posthog-foss

    Official

    Debug the output of local PostHog task runs — the wizard cloud-run path that executes inside a Docker sandbox under the local Temporal process-task workflow (the wizard that integrates PostHog, then…

    721 GitHub stars~2.1k tokensUpdated today
    DevelopmentAuto-check: notes

More from nubjs/nub

All 31 skills in this repo

  • Cpu Reduction

    nubjs/nub

    Diagnose and clear CPU, memory, and disk contention on the maintainer's dev host.

    4.4k GitHub stars~2.8k tokensUpdated today
    Auto-check passed

  • Disk Reduction

    nubjs/nub

    Reclaim disk on the maintainer's Mac when the volume is full or filling — ENOSPC, "no space left on device", a failed build or agent harness, or a routine sweep of Rust build residue.

    4.4k GitHub stars~2.4k tokensUpdated today
    Auto-check passed

  • Nub Charts

    nubjs/nub

    Build a performance chart for nubjs.com — the SVG bar figures in blog posts, docs pages and social posts (a runtime augmentation against plain node, an install or dispatch comparison, a cross-tool…

    4.4k GitHub stars~4.6k tokensUpdated today
    Auto-check passed

  • Audit Thread

    nubjs/nub

    A skill your agent uses when running a compatibility/parity AUDIT — enumerating where nub diverges from a reference it claims parity with (pnpm CLI grammar, a lockfile format, a Node behavior, a…

    4.4k GitHub stars~1.8k tokensUpdated today
    Auto-check passed

  • Pm Perf Tracing

    nubjs/nub

    Performance-trace Nub package-manager installs using the existing phase timings, structured diagnostics, and sampling-profiler workflow.

    4.4k GitHub stars~1.3k tokensUpdated today
    Auto-check passed

  • Rust Build

    nubjs/nub

    A skill your agent uses when building or testing the nub Rust workspace inside a git worktree — cargo build/test/clippy for nub-cli/nub-core/aube in a worktree off origin/main.

    4.4k GitHub stars~4.4k tokensUpdated today
    Auto-check passed

Works with

Categories

Questions about Linux Vm Test

What does Linux Vm Test do?

Run ad-hoc Nub tests and debugging probes on real local Linux guests. Linux Vm Test is an agent skill from nubjs/nub. Run ad-hoc Nub tests and debugging probes on real local Linux guests.

When should I use Linux Vm Test?

Linux Vm Test fits situations like: linux-specific sandbox; runtime behavior that Docker cannot reproduce faithfully.

How do I install Linux Vm Test in Claude Code?

Run `npx skills add nubjs/nub --skill linux-vm-test -a claude-code`. Or copy the skill folder (.claude/skills/linux-vm-test in nubjs/nub) into .claude/skills/linux-vm-test in your project. Claude Code loads it when a task matches its description.

How do I install Linux Vm Test in Codex?

Run `npx skills add nubjs/nub --skill linux-vm-test -a codex`. Or copy the skill folder (.claude/skills/linux-vm-test in nubjs/nub) into .agents/skills/linux-vm-test in your project. Codex loads it when a task matches its description.

Can I use Linux Vm Test in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add nubjs/nub --skill linux-vm-test -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/linux-vm-test, .gemini/skills/linux-vm-test, .github/skills/linux-vm-test and .opencode/skills/linux-vm-test in your project.

What does Linux Vm Test need to run?

Going by SKILL.md and its folder, Linux Vm Test needs the command-line tools its instructions call (cargo and rsync). Our summary lists: Docker.

Does Linux Vm Test access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Linux Vm Test safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Linux Vm Test use?

Linux Vm Test is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Linux Vm Test use?

About 986 tokens (SKILL.md is roughly 3.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Linux Vm Test?

Skills that share tags, products or a category with Linux Vm Test: Dotnet Debugging (novotnyllc/dotnet-artisan, 233 stars), .NET Crash Dump Collection (dotnet/skills, 5.6k stars), Linux Troubleshooting with Inspektor Gadget (inspektor-gadget/inspektor-gadget, 2.9k stars) and Debug CI (web-infra-dev/rslint, 460 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Linux Vm Test?

nubjs (a GitHub organization) maintains it in nubjs/nub, which has 4,370 GitHub stars. The repository holds 31 skills in this directory. The repository was last updated on October 7, 2026.

Source: nubjs/nub on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.