The mobile-check skill: see your page the way phones show it

You built it on a laptop. Most people who open it will be on a phone, one-handed, half distracted. A page that looks fine at 1440 pixels wide can be unusable at 375, and you'd never find out, because you never looked at it that way.

The mobile-check skill reads your page at phone width and tells you what breaks: text too small to read, buttons too small to tap, a page that slides sideways, an image blowing out the layout, and the main button parked where a thumb can't reach it. Then it ranks the problems by how much each one costs you, so you fix the one that matters first.

The part that makes it useful for a beginner is the paste-back sentence. Every fix comes written as one plain sentence you copy into your next message. No selectors, no pixel values, nothing you'd have to understand. The skill is free and it sits in our public freeskills repo.

Grab the repo, then drop this folder into your Claude Code skills directory.

Restart Claude Code or open a new session and it's live. No API keys, no setup.

Type /mobile-check. It asks for the file path of the page. If you don't know it, it looks for the index.html you've been working on and confirms with you before reading anything. Then it reads the whole file, the HTML and the CSS and any JavaScript inside it, and tells you out loud that it's reading the page as a phone at 375 pixels wide.

What comes back is a numbered list. Each item says what's wrong, where it is, why it costs you, and the sentence to paste. It also gives you a short already-good list, because you need to know what not to touch. The report saves to ~/mobile-checks/<page-name>-<date>.md. Honest expectation: if your page is a paragraph of text with no styling, it'll tell you it's fine rather than invent problems for you.

The normal run. Point it at the file and let it read.

If it's deployed and someone told you it looks weird on their phone, give it the link and what they said.

This is where the skill pays off. Take fix number one, paste it, look at the page, come back. Fixing eight things in one prompt is how a working page turns into a broken one.

What this skill does and why it's worth running before anyone else opens your page. Sixty seconds, out loud.

1. 1Hook: there's a brand new free Claude skill that takes you from a page that quietly breaks on phones to a ranked fix list with the exact words to paste back.
2. 2Mechanism: you hand it the page you built, and it reads the whole thing the way a phone at 375 pixels wide would see it. It runs seven checks for the things that actually break, the sideways scroll, the text too small to read, the button no thumb can hit, then ranks what it finds by how much each one costs you. Every problem comes back with one plain sentence you paste straight back to get it fixed.
3. 3Transformation: you stop guessing about the half of your visitors you can't see. You know what's broken, in what order it matters, and how to say it.
4. 4Close: it's free, one of 55 sitting in the repo. Knowing what to build so you've got pages worth checking is the bigger job, and that runs inside Claude Code Club for $9 a month. Link's below.

Tonight: run it on the last page you built, do fix number one, and open the page on your actual phone to see the difference.