choose-macos-virtualization-shape

A guide for choosing a development or testing boundary on a Mac, such as the host, a container, a container machine, a full Linux or macOS virtual machine, a remote system, or a physical Mac.

In plain words
What is it for?
Use it to choose a boundary for macOS development, Linux compatibility, clean-state validation, custom virtual-machine tools, or authorised security research.
Why use it?
It prevents different kinds of isolation from being treated as interchangeable when they differ in operating-system fidelity, persistence, portability, host access, risk, and resource needs.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/gaelic-ghost/socket/choose-macos-virtualization-shape
Any agent
npx skills add gaelic-ghost/socket --skill choose-macos-virtualization-shape
Clone the repo
git clone --depth 1 https://github.com/gaelic-ghost/socket

Made for: Claude Code, Codex.

Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 953 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00054 $0.00953
Opus 5 $0.00027 $0.00477
Sonnet 5 $0.00011 $0.00191
Haiku 4.5 $0.00005 $0.00095

Measured 2d ago against content hash 073538e28ebb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

choose-macos-virtualization-shape scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/apple-dev-skills/skills/choose-macos-virtualization-shape/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Choose macOS Virtualization Shape

Purpose

Choose one boundary from evidence about fidelity, persistence, portability, host integration, threat level, and resources. Produce the shared shape record in virtualization-shape-record.md; do not return an undecided product menu.

When To Use

  • Use for macOS-hosted development, clean-state validation, Linux compatibility, custom VM tools, and security-lab boundary selection.
  • Use when container, persistent Linux machine, full VM, and physical Mac terminology is being mixed.
  • Use before virtualization-framework-workflow, either development-VM workflow, or prepare-isolated-analysis-lab when the boundary is not already approved.

Single-Path Workflow

  1. Record the purpose, host, target OS and architecture, GUI/headless needs, privileges, kernel/devices, expected lifetime, and evidence requirements.
  2. Classify fidelity and risk:
    • trusted native macOS behavior: host process
    • one portable Linux application: OCI container
    • Apple-native per-container VM runtime: Apple container
    • persistent OCI-backed Linux environment with services: container machine
    • custom kernel, boot, disk, full-system, or GUI Linux: full Linux VM
    • native macOS security, installer, signing, privacy, or OS-version behavior: macOS VM
    • hardware, recoveryOS, Secure Enclave, unsupported device, performance, or anti-VM behavior: physical Mac
  3. Reject any option that cannot reproduce the target or safely bound the expected behavior.
  4. Choose one primary boundary and one explicit fallback only when a named fidelity or availability gap requires it.
  5. Complete the shape record with provenance, resources, integrations, lifecycle, validation, evidence, and uncertainty.
  6. Hand off implementation or operation to the owner skill.

Inputs

  • Task purpose and target behavior.
  • Host chip, macOS build, memory, storage, and toolchain.
  • Guest OS/version/distro, architecture, devices, privilege, and lifetime.
  • Portability, persistence, integration, isolation, and evidence requirements.

Read the full file on GitHub · 72 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 72 lines · 54 tokens per session scan A 073538e28ebb

Subscribe to this mod's changes

choose-macos-virtualization-shape is a skill published in the GitHub repository gaelic-ghost/socket (7 stars, last pushed 7d ago), licensed Apache-2.0. It adds 54 tokens to every session and 953 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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