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Guide · Agent skill

How to use the ComputerUse agent skill for Mac

Updated · written with AI from the project's own documentation and checked against our catalogue data

ComputerUse is an agent skill, a folder of instructions and scripts that an AI agent such as Claude loads when a task matches its description. This one teaches the agent to operate your Mac for you. This guide explains what it does, how to install it, how to ask for work in plain language, and which safety limits apply, so you can decide whether it fits your setup.

Mac Computer Use Routerdanielmiessler/LifeOS · MIT

Quick start

  1. 1Confirm macOS and Interceptor. Check that you are on a Mac with Interceptor installed and its preflight passing. Run interceptor macos frontmost to confirm the Mac is unlocked.
  2. 2Install Bun and the Codex app. Install the Bun runtime to execute the TypeScript tools. For the Astra leg, install the Codex desktop app and add the bundled computer-use plugin.
  3. 3Download and unzip the skill. Download the ComputerUse ZIP from the directory page and unzip it into ~/.claude/skills/ or a project's .claude/skills/ folder.
  4. 4Create your Config.md. Copy Config.example.md to LIFEOS/USER/CUSTOMIZATIONS/SKILLS/ComputerUse/Config.md and set your deny lists, step cap and wall clock limit.
  5. 5Grant macOS permissions and probe. Grant accessibility and screen recording permissions as described in Setup.md, then run Tools/Probe.ts to check the vision leg.
  6. 6Make a natural request. Ask for the task in plain language, name the app and the visible end state, and say whether it should be done in the GUI.

What the ComputerUse skill makes the agent do

The skill first decides how each task should be done. If the target has a handle the system can reach directly, such as a DOM element, an accessibility (AX) element, a CLI or an API, the work goes to Interceptor. Verification and evidence checks always go to Interceptor.

If the work is purely visual, with no handle to grab, the skill sends it to a vision agent. The source names two options: OpenAI Astra, run through codex exec, or a tool-less Claude acting through Interceptor's bridge. Which one is used for a given app is set by a measured bake-off, not by guesswork.

  • Drive apps with structured interfaces through Interceptor.
  • Hand pixel-only canvas or GUI work to a vision agent.
  • Run each vision task under a deny list, step caps and a read-back that decides pass or fail.

Install the ComputerUse skill

Download the ComputerUse ZIP from the directory page and unzip it. Put the folder in ~/.claude/skills/ to make it available everywhere, or in a project's .claude/skills/ folder to limit it to that project.

Alternatively, upload the skill in the Claude apps under Settings → Capabilities → Skills.

Installing the files is not the whole setup. The skill needs a user Config.md, the Codex app and plugin for the Astra leg, and macOS permissions. Follow the included Setup.md for those steps.

  • Requirement: macOS. The scripts depend on macOS APIs, Apple Events and Interceptor.
  • Requirement: Interceptor installed, with its preflight passing.
  • Requirement: Bun runtime to execute the TypeScript tools.
  • Create your Config.md at LIFEOS/USER/CUSTOMIZATIONS/SKILLS/ComputerUse/, starting from Config.example.md. Without it the skill refuses to run rather than running with empty deny lists.
interceptor macos frontmost

Set up the Astra leg and permissions

The Astra leg needs the Codex desktop app, not just codex-cli. The computer-use tool comes from the app's bundled plugin, so install the app, then add the plugin. Without the app, the CLI and interactive interface show no computer-use tool.

Grant the macOS permissions for accessibility and screen recording as described in Setup.md. Then run Tools/Probe.ts, which checks the vision leg. Re-run it after any Codex or app upgrade.

Before any live run, check the frontmost app. A locked Mac blocks input and Apple Events, so a dry check can pass while a live run fails. Frontmost reading loginwindow means the Mac is locked.

codex plugin add computer-use@openai-bundled

How to trigger the skill with natural requests

You do not need special syntax. The skill's description lists the phrases that should activate it. Name the app and the end state you want, and say that the work should happen in the GUI if no API exists.

Phrases that match the skill include: computer use, drive the computer, control the mac, operate this app for me, do it in the GUI, pixel-only app, no API for this, canvas UI, and Claude vs OpenAI computer use.

Requests about DOM or AX handles, or web verification, belong to Interceptor. Scraping belongs to a separate scraping skill, such as one using BrightData. Expect ComputerUse to hand those off.

  • Example: Operate this app for me and set the canvas size to the value in the brief, then stop.
  • Example: Do this in the GUI: open the export dialog in the design app and save as PNG to the folder I name.
  • Example: Run the computer use bake-off for the canvas app and tell me which vision agent wins.
  • Example: Drive the computer for the pixel-only app and report the final visible state.

Safety limits: deny lists, caps and scripts

The skill is built to be supervised. Credential-class apps may not be running during a run. Communications apps may not be visible, though hiding them with Cmd+H is allowed. Browser tabs on denied hosts block the run. The runner checks these before starting and watches them during the run.

The default limits are 60 steps and 10 minutes. The vision agent may only act inside the allowlisted app, and the run stops if the frontmost app leaves it. The run's verdict comes only from the verifier script's exit code, never from the agent's own report.

The skill runs scripts and uses the network. The vision agent is also instructed never to send, purchase, delete, publish or confirm anything unless you named that exact action. Those requests stop the run and are reported.

  • Refused runs exit with a clear code: headless channel, failed Interceptor preflight, no verifier, or a deny-list hit.
  • A deny list or verifier that you misconfigure can still expose data or cause unintended actions. Review Config.md carefully.
  • Keep your own credential and messaging apps closed. The skill will not hide or quit them for you.

What people use it for

  • Operating a canvas or pixel-only design app where no API exists.
  • Running a cross-app GUI flow that no script covers, under a deny list that keeps password managers and messages closed.
  • Comparing Astra and Claude on your own pixel-only apps with the included bake-off tooling.
  • Checking that a requested visible state appears in an app, with the verifier deciding pass or fail.
  • Routing DOM or AX-accessible work to Interceptor while keeping GUI-only steps in a bounded vision run.

Frequently asked questions

Is the ComputerUse skill free to use?

The source confirms the skill is released under the MIT licence. It does not state pricing for the Codex app, Claude access or Interceptor, so check those separately before you rely on them.

What do I need to install ComputerUse?

You need a Mac, Interceptor installed with its preflight passing, the Bun runtime, a Config.md in the USER customizations folder, the Codex app and plugin for the Astra leg, and Claude access for the Claude leg. Setup.md covers the macOS accessibility and screen recording permissions.

How do I install an agent skill like this?

Download the ZIP, unzip it into ~/.claude/skills/ for all projects or a project's .claude/skills/ folder for one project. You can also upload it in the Claude apps under Settings → Capabilities → Skills.

Why does the skill refuse to run?

Refusals are deliberate. It exits when the channel is headless, when the Interceptor preflight fails, when no verifier is declared, when Config.md is missing, or when a denied app or host is detected. The message names the cause.

Claude vs OpenAI computer use: which is better?

The skill does not declare a winner. It picks the vision agent per app class from measured results of its bake-off tooling, so the answer depends on your own apps. Run the bake-off on your target app to find out.

Can ComputerUse scrape websites or send emails for me?

No. Scraping is routed to a separate scraping skill, and DOM or AX work and web verification go to Interceptor. Sending, buying, deleting and publishing are excluded and stop the run by design.

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Our verdict

ComputerUse suits developers and power users who already run Interceptor and want a documented, supervised way to let an agent drive Mac apps, including teams comparing vision models on canvas interfaces. It is a poor fit if you lack a Mac, want unsupervised actions like sending or buying, or are looking for simple web scraping, which the skill hands to another tool.

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