Claudback

Comment on your page.
Claude reads it.

Claudback is a Chrome extension that lets you pin comments to elements on any web page, plus a local MCP server that lets Claude read them and make the changes.

Get the extension
localhost:5173 yoursite.com 1 <button> #app › div › button “Make this bigger” Add comment Claude Code > Hey Claude, check my claudback comments ● get_comments 1 · “Make this bigger” #app › div › button editing button.css… ✓ resolved

Iterate on your build without describing it

If you're anything like me when you're building a site or prototype locally and iterating with Claude, you find yourself screenshotting, or typing "the second button in the header, no, the other one". It can be slow and frustrating. That's where Claudback comes in: you click the exact thing on the page and say what you want. Each comment carries the exact element, so Claude knows precisely what you mean.

  1. Run your app locally and open it in Chrome. Click the Claudback icon and enable it for the tab.
  2. Pin comments to anything on the page: "make this bigger", "wrong green", "this overlaps on mobile".
  3. Ask Claude Code: Grab my Claudback comments. Claude reads each comment, with its element selector, through the MCP server.
  4. Comments resolve as Claude works through them. Reload, look at the result, drop the next round of comments.

It's not just for local builds. Annotate any site to collect structured, element-anchored notes for Claude to work from. Useful for competitor teardowns, PRDs, design reviews and content audits.

How it works

Chrome extension pins + comments
→
Local collector 127.0.0.1:57463
→
Claude MCP tools

The claudback-mcp server runs on your machine, started and stopped by Claude itself. It embeds a small HTTP collector that only listens on localhost. The extension syncs your comments to it; Claude reads them through MCP tools (get_comments, list_origins, resolve_comment, clear_comments).

Quick start

Install the extension from the Chrome Web Store. A setup guide opens automatically and walks you through the following:

  1. Register the MCP server, one command that the guide has you run in a terminal, or paste straight into a Claude Code chat if you use the desktop app: 
    claude mcp add --scope user claudback -- npx -y claudback-mcp
  2. Pair the extension. Ask Claude for a pairing code and enter it on the setup page. You'll be commenting in a couple of minutes.

Privacy

Local only

The collector binds to 127.0.0.1, so it is never reachable from the network. Your comments live in ~/.claudback/ on your own machine. No remote servers, no accounts, no analytics.

Paired & permissioned

Every request needs the pairing token, and only the extension's own origin passes CORS, so a random web page can't write into your comment store. Pairing itself uses a short-lived, single-use code (10-minute expiry, five-attempt cap), so the long-lived token never appears in a chat. The extension is off by default and enabled per tab, with per-site permissions granted only when you ask.

Pull, not push

Comments never enter Claude's context automatically. Claude reads them only when you ask it to call the tools, and each comment is wrapped in an untrusted-data envelope.