For Claude, ChatGPT, Codex, Cursor…

Ask your AI if it fits.

Connect doesitfit once, then just ask “does my site fit on an iPhone?” in Claude, ChatGPT or Codex, on your computer or your phone. It opens your site on real screen sizes, tells you what spills, and shows screenshots with the problem outlined.

The address to paste in
https://doesitfit.lol/mcp

No sign-up and no password. Works with public websites. For localhost, see “On your computer” below.

Set it up (1 minute)

  • C

    Claude

    claude.aiDesktop appiPhone & Android
    1. On claude.ai (or the desktop app) open Customize → Connectors.
    2. Press + → Add custom connector.
    3. Name it doesitfit and paste the address above.
    4. Under Authentication, choose No sign‑in, then press Add.

    Important: choose “No sign‑in”. doesitfit doesn’t need an account, so there’s nothing to sign in to.

    If you pick Sign in now, Claude shows “Couldn’t register with Doesitfit’s sign-in service”. Claude can’t change this afterwards, so remove the connector and add it again with No sign‑in.

    It then shows up in the Claude apps on your phone too. Works on every plan (the free plan can add one custom connector). On Team and Enterprise plans an owner may need to allow it first.

  • G

    ChatGPT

    chatgpt.com (web)Plus, Pro, Business, Enterprise
    1. Open Settings → Security and login and turn on Developer mode.
    2. Go to Plugins, press + and create a developer-mode app: name it doesitfit, paste the address above, choose No authentication.
    3. In a chat, pick Developer mode from the + menu and select doesitfit.

    Developer mode works on the ChatGPT website with a paid plan. ChatGPT’s menus move around; if these don’t match, search its help for “developer mode”.

  • >_

    Claude Code or Codex

    Paste this in your terminal. Claude Code:

    claude mcp add --transport http doesitfit https://doesitfit.lol/mcp

    Codex (the Codex app: Settings → MCP servers → Add server, and paste the address above):

    codex mcp add doesitfit --url https://doesitfit.lol/mcp
  • { }

    Cursor, Windsurf, VS Code…

    Add this to your MCP settings (in Cursor: .cursor/mcp.json):

    {
  "mcpServers": {
    "doesitfit": { "url": "https://doesitfit.lol/mcp" }
  }
}
  • ⌂

    On your computer, for localhost

    The online version can’t see sites that only run on your computer. This version runs on your computer, so it can check localhost:3000 and friends. You need Node.js and Google Chrome (or Edge, Brave, Chromium) installed.

    Claude Code:

    claude mcp add doesitfit-local -- npx -y https://doesitfit.lol/downloads/doesitfit-mcp-1.0.0.tgz

    Codex:

    codex mcp add doesitfit-local -- npx -y https://doesitfit.lol/downloads/doesitfit-mcp-1.0.0.tgz

    Claude Desktop or Cursor (Claude Desktop: Settings → Developer → Edit Config):

    {
  "mcpServers": {
    "doesitfit-local": {
      "command": "npx",
      "args": ["-y", "https://doesitfit.lol/downloads/doesitfit-mcp-1.0.0.tgz"]
    }
  }
}

    Using Claude Code or Codex? You can also just paste this page’s address and ask it to set doesitfit up for you.

Then just ask

Does mybakery.com fit on an iPhone 18 Pro and a Galaxy S25? Use doesitfit.
Check localhost:3000 on phones, a tablet and a MacBook with doesitfit, then fix anything that spills.
Which screen sizes does doesitfit know for Samsung phones?

What your AI gets back

  • For every screen: Fits, Tight (text squeezed against the edge) or Spilling +24px (the page is wider than the screen and wobbles sideways).
  • The exact element that sticks out or hugs the edge, so it can fix the right thing.
  • Screenshots at the real screen size, with the problem outlined.
  • A link that opens the same screens in the doesitfit app, so you can see it yourself.

Pages are opened in Chrome’s engine at each device’s exact screen size. Safari-only quirks and fonts can differ slightly. To keep it free, each site can be checked a few dozen times an hour.