serve-sim: Skill for Claude Code

.codex/skills/serve-sim-placeholder-assets/SKILL.md

serve-sim-placeholder-assets is a skill for Claude Code, Codex from EvanBacon/serve-sim. It costs 56 tokens per session (203 once invoked), scanned A, original, Apache-2.0.

A maintenance workflow for the placeholder device images shown by serve-sim when an Apple simulator is not running. It checks local Xcode and macOS resources for iPhone, iPad, Apple Watch, and Vision device previews.

In plain words
What is it for?
Use it to audit and update serve-sim’s placeholder assets, then decide whether application code or tests need changes based on the audit results.
Why use it?
It helps find why device previews look incorrect after installing a new Xcode version or macOS test release, and separates exact, fallback, and missing asset mappings.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also installed under .codex/. Also seen: mentions Codex.

This is EvanBacon/serve-sim's own configuration. It tells Claude Code and Codex how to work on serve-sim itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything serve-sim configures →

Part of the serve-sim plugin — 2 skills shipped together

About the project

serve-sim is a command-line tool for serving Apple Simulator applications or files over a network, similar to how `npx serve` serves web files. It is used for headless iOS development workflows, and the catalogue entries provide agent instructions and skills for operating it.

EvanBacon/serve-sim · 2,775 stars · on GitHub

Reuse

Borrowing it

Nothing to install: this file belongs to EvanBacon/serve-sim. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/EvanBacon/serve-sim/main/.codex/skills/serve-sim-placeholder-assets/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/EvanBacon/serve-sim

Made for: Claude Code, Codex.

Or install serve-sim, the plugin that ships this one along with the rest of its 2 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for serve-sim-placeholder-assets

README.md
[![agentmods](https://agentmods.dev/badge/skills/evanbacon/serve-sim/serve-sim-placeholder-assets/github.svg)](https://agentmods.dev/skills/evanbacon/serve-sim/serve-sim-placeholder-assets)
Your own site
<a href="https://agentmods.dev/skills/evanbacon/serve-sim/serve-sim-placeholder-assets"><img src="https://agentmods.dev/badge/skills/evanbacon/serve-sim/serve-sim-placeholder-assets/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for serve-sim-placeholder-assets

Your own site · 80×15
<a href="https://agentmods.dev/skills/evanbacon/serve-sim/serve-sim-placeholder-assets"><img src="https://agentmods.dev/badge/skills/evanbacon/serve-sim/serve-sim-placeholder-assets.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 203 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00056 $0.00203
Opus 5 $0.00028 $0.00102
Sonnet 5 $0.00011 $0.00041
Haiku 4.5 $0.00006 $0.00020

Measured 11d ago against content hash bcdb265a9df3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

serve-sim-placeholder-assets 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 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/audit-placeholder-assets.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.codex/skills/serve-sim-placeholder-assets/SKILL.md · 21 lines

What it actually says

serve-sim Placeholder Assets

Use this project-scoped skill when updating the not-running device preview images in this repo.

Workflow

  1. Read references/device-placeholder-assets.md.

  2. Run the audit script from the repo root:

    node .codex/skills/serve-sim-placeholder-assets/scripts/audit-placeholder-assets.mjs --out tmp/device-placeholder-assets
    
  3. Keep the public skills/serve-sim skill focused on end-user CLI usage; do not add this internal asset-maintenance workflow there.

  4. Update app code/tests only after reviewing the audit output for exact, fallback, or missing mappings.

Files

What ships with it

2 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. 11d ago First seen · 21 lines · 56 tokens per session scan A bcdb265a9df3

Subscribe to this mod's changes

serve-sim-placeholder-assets is a skill published in the GitHub repository EvanBacon/serve-sim (2,775 stars, last pushed 12d ago), licensed Apache-2.0. It adds 56 tokens to every session and 203 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 2026-08-30.

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