How to use the Mobile Three.js Game Builder agent skill

What the skill makes the agent do

Once installed, the agent follows guidance that treats mobile as a primary control and performance surface rather than an afterthought. It covers touch movement, action controls, target selection, touch-friendly inventory, safe areas, portrait and landscape layouts, a responsive HUD, and battery and performance budgets.

The skill is written for building, tuning or testing a Three.js game for the mobile web. Its guidance targets the mobile browser, not native iOS or Android engines.

• Controls: a clear movement control, reachable primary actions, target selection, cancel or reset paths, and non-drag alternatives for inventory.
• Layout: keep vital status, target data, inventory, tooltips and dialogs legible without covering the playfield, and keep gameplay state when the device rotates.
• Performance: device-appropriate quality defaults and adaptive decorative effects.
• QA: test touch targets, multi-touch, long sessions, audio unlock, pause and background return, reduced motion, low-end quality, and mobile-size viewports in the repository-approved browser.

How to install the build-mobile-threejs-games skill

Download the ZIP for this skill from this page, then unzip it. The skill is made of two files: SKILL.md and agents/openai.yaml. Put the unzipped skill folder in one of these locations:

• Personal skills folder: ~/.claude/skills/
• Project skills folder: .claude/skills/ inside your game's repository
• Claude apps: upload the skill under Settings → Capabilities → Skills

How to trigger the skill with natural requests

You do not need special syntax. The skill's description lists the topics it covers, so ask for mobile work in plain language that mentions one of those topics. The more specific your request, the more useful the agent's output will be.

• Build a touch movement control for my Three.js game on phones.
• Make the HUD work in both portrait and landscape without covering the play area.
• Tune my Three.js game's performance for battery life on mid-range phones.
• Give me a checklist for testing my game in a mobile browser, including audio unlock and returning from background.

Examples of what you can ask for

Most requests fall into three groups: building new controls or layout, tuning an existing game, or testing. The skill is most useful when you name the screen size, the orientation or the problem you saw on a device.

• Adding an on-screen action button that is reachable with one thumb and does not sit in unsafe screen areas.
• Reviewing an inventory that relies on drag and drop and suggesting a non-drag alternative.
• Checking that the game keeps its state when a phone is rotated mid-session.
• Writing a QA pass that covers multi-touch, long sessions and reduced motion.

What you need before you start

The skill lists no required tools, runs no scripts and makes no network calls. You still need your own Three.js project to work on, and you will need a mobile browser or mobile-sized viewport to test in, as the skill's QA guidance asks you to use the repository-approved browser.

• A Three.js game in a repository (the skill is built for Three.js projects).
• Access to a mobile-sized browser viewport or a real phone for testing.
• No scripts or network access are required by the skill itself.

Safety notes on scripts and network access

According to its listing, this skill does not run scripts and does not use the network. Its files are SKILL.md and agents/openai.yaml, which are guidance text. Because it is MIT licensed, you can read the files before installing to confirm they match what you expect.

The skill guides the agent's decisions, but it does not replace testing. Check the agent's changes on real devices or mobile-sized viewports before you ship.

• Read SKILL.md and agents/openai.yaml before installing.
• Run the changes the agent makes through your own tests and device checks.

Tips for getting better results

Give the agent your target devices, the orientations you need to support, and the screen areas you know are unsafe. Those details let the guidance produce specific layouts instead of generic ones.

• Name the problem you saw on a device, such as a button under a notch or a HUD covering enemies.
• Ask for a QA checklist in addition to code changes, so you have a repeatable test pass.
• Re-run the QA checklist after performance changes, since quality settings affect both battery use and visual output.