app_control

A guide for viewing and operating macOS applications such as VS Code, Terminal, Finder, Safari, Chrome, and messaging apps. It describes how to inspect windows and perform clear user-requested actions.

In plain words
What is it for?
Use it to identify the active app, read its interface, activate an app, type, press keys, click menus, or take a screenshot when needed. It also handles unknown app names and reports whether an action succeeded.
Why use it?
It reduces ambiguity when controlling an app and adds a confirmation step after an action.

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/blockcell-labs/blockcell/app_control
Any agent
npx skills add blockcell-labs/blockcell --skill app_control
Clone the repo
git clone --depth 1 https://github.com/blockcell-labs/blockcell

Made for: Claude Code, Codex.

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 416 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 $0.00000 $0.00416
Opus 5 $0.00000 $0.00208
Sonnet 5 $0.00000 $0.00083
Haiku 4.5 $0.00000 $0.00042

Measured 2d ago against content hash cb8ed9bd53f3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

app_control 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.

skills/app_control/SKILL.md · 33 lines

What it actually says

App Control

Shared {#shared}

  • 适合查看或操作 macOS 应用,例如 Windsurf、VS Code、Terminal、Finder、Safari、Chrome、微信、飞书。
  • 常用名称映射:
    • Windsurf -> Windsurf
    • VS Code / vscode -> Code
    • 终端 -> Terminal
    • 访达 -> Finder
    • Chrome -> Google Chrome
    • 飞书 -> Lark
  • 如果用户没有明确应用名,但问题明显是在问当前前台应用,可先获取前台应用再继续。

Prompt {#prompt}

  • 只有在“目标应用不明确”或“要执行的动作不明确”时才澄清。
  • 查看应用当前状态时,优先策略:
    1. 如果未给应用名且明显在问当前界面,先用 app_control 获取 frontmost app。
    2. 优先用 read_ui 获取界面结构,默认从较浅层开始。
    3. 只有在用户明确要截图,或需要给用户留存视觉证据时,才补 screenshot
  • 执行动作时,优先策略:
    1. 必要时先 activate
    2. 再执行 press_keytypeclick_menu 等单个明确动作
    3. 执行后用 read_uiscreenshot 做一次确认
  • 如果应用名解析失败,先用 list_apps 判断是否在运行,再告知用户。
  • 输出要求:
    • 说明目标应用
    • 说明执行的动作或读到的当前状态
    • 说明结果是否成功
    • 如果还差一步才能完成,给出下一步建议
  • 不要连续触发多次不必要的界面操作,不要输出 AppleScript 或内部控制细节。
Files

What ships with it

4 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 · 33 lines · 0 tokens per session scan A cb8ed9bd53f3

Subscribe to this mod's changes

app_control is a skill published in the GitHub repository blockcell-labs/blockcell (263 stars, last pushed 18d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 416 tokens. 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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