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.
npx skills add rshankras/claude-code-apple-skills --skill app-extensionsgit clone --depth 1 https://github.com/rshankras/claude-code-apple-skillsWrote 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.
[](https://agentmods.dev/skills/rshankras/claude-code-apple-skills/app-extensions)<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/app-extensions"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/app-extensions/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.
<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/app-extensions"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/app-extensions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 8 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 36 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 84 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 88 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 92 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 121 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 128 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 135 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- low Privilege Escalation · line 250 Skill requests more permissions than appear necessary for its stated functionality. Review if elevated access is justified.Fix: Request only the minimum permissions required. Document why each permission is needed. Remove broad permissions like '*' or 'all'.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00056 | $0.02209 |
| Opus 5 | $0.00028 | $0.01104 |
| Sonnet 5 | $0.00011 | $0.00442 |
| Haiku 4.5 | $0.00006 | $0.00221 |
Grade A, and why
app-extensions 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 272 lines — stays where its author put it; the contents beside it link to each section on GitHub.
App Extensions Generator
Generate production app extension infrastructure -- Share Extensions for receiving content from other apps, Action Extensions for manipulating content in-place, Keyboard Extensions for custom input, and Safari Web Extensions for browser integration. Includes App Group data sharing between the host app and extensions.
When This Skill Activates
Use this skill when the user:
- Asks to "add a share extension" or "share sheet extension"
- Wants to "receive content from other apps" or "accept shared content"
- Mentions "action extension" or "content manipulation extension"
- Wants to "add a custom keyboard" or "keyboard extension"
- Asks about "Safari extension" or "Safari web extension"
- Mentions "app extension" or "extension target" generically
- Wants to "share data between app and extension" or "App Groups"
Pre-Generation Checks
1. Project Context Detection
- Check deployment target (iOS 16+ / macOS 13+)
- Check Swift version (requires Swift 5.9+)
- Identify project structure (find .xcodeproj or Package.swift)
- Identify source file locations
2. Existing Extension Detection
Search for existing extension targets:
Glob: **/*Extension*/*.swift, **/*Extension*/Info.plist
Grep: "NSExtensionPointIdentifier" or "NSExtensionPrincipalClass"
If existing extensions found:
- Ask if user wants to add another or modify existing
- Identify existing App Groups configuration
3. App Groups Detection
Check for existing App Groups setup:
Glob: **/*.entitlements
Grep: "com.apple.security.application-groups"
If App Groups exist, reuse the existing group identifier.
Configuration Questions
Ask user via AskUserQuestion:
- What type of extension?
- Share Extension (accept content from other apps, display share UI)
- Action Extension (manipulate content in-place -- transform text, edit images)
- Keyboard Extension (custom input keyboard with KeyboardViewController)
- Safari Web Extension (inject JavaScript/CSS into web pages)
What ships with it
1 file 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.
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.
- 9d ago First seen · 272 lines · 56 tokens per session scan A a0dbfc3aaaaa
app-extensions is a skill published in the GitHub repository rshankras/claude-code-apple-skills (710 stars, last pushed 1mo ago), licensed MIT. It adds 56 tokens to every session and 2,209 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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