UI Annotator MCP

Name: UI Annotator MCP
Author: mcpware

by mcpwareversion 0.1.6i★ –iRuns on your computer

Registry nameio.github.mcpware/ui-annotator-mcp

Install

Overview

Description from the maker (original English)

Annotates any web page with hover labels for AI assistants — zero extensions, any browser

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Web & browsers

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "ui-annotator": {
      "command": "npx",
      "args": [
        "-y",
        "@mcpware/ui-annotator"
      ]
    }
  }
}

Run this in your terminal

claude mcp add ui-annotator -- npx -y @mcpware/ui-annotator

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "ui-annotator": {
      "command": "npx",
      "args": [
        "-y",
        "@mcpware/ui-annotator"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "ui-annotator": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@mcpware/ui-annotator"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account mcpware, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Web & browsersi

More stars than 0% of the other 878 servers in this category
Published to the registry more recently than 6% of the other 878 servers in this category
Basic checks equal to or better than 100% of the other 878 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is UI Annotator MCP safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.6) reached the registry 8 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Browser Use, Chrome DevTools MCP, MCP Server Browser

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Browser Use

by browser-use

Lets AI do web tasks for you, such as filling forms, searching and extracting data, in the maker’s cloud browsers or on your computer.

Computer or cloud★ 120,087MITUpdated 17 days ago

Install

Chrome DevTools MCP

by ChromeDevTools

Lets AI use Chrome’s developer tools to inspect pages, find what makes them slow and spot errors. Made by the Chrome DevTools team.

Runs on your computer★ 54,821Apache-2.0Updated 15 days ago

Install

MCP Server Browser

by bytedance

MCP server for browser use access

Runs on your computer★ 39,550Apache-2.0Updated 14 months ago

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

UI Annotator MCP

English | 廣東話

Bridge the gap between what you see and what AI can reference — in any browser, zero extensions.

The only tool that puts visible labels on every web element. Hover any element, see its name. Tell your AI assistant "make the sidebar wider" — it knows exactly which element you mean. No screenshots, no CSS selectors, no miscommunication.

Why It Matters

Dramatically improves AI-driven UI design and iteration. The pain: telling AI "move that button next to the search bar" never works because the AI can't see your page. UI Annotator fixes this — hover over any element and its component name appears as a label. Now you say "move SearchButton below NavBar" and Claude edits the right component instantly. No browser extensions, works with any framework. The workflow becomes: open page → hover to identify elements → describe changes using real component names → Claude edits → refresh and repeat. Turns a frustrating back-and-forth into a fluid design loop.

The Problem

When reviewing a web UI with an AI coding assistant, the hardest part isn't the code change — it's describing which element you want changed.

"That thing on the left... the second row... no, the one with the icon..."

You don't know what it's called. The AI doesn't know what you're pointing at. You waste time on miscommunication instead of shipping.

The Solution

Open your page through the annotator proxy. Hover any element — instantly see its name, CSS selector, and dimensions. Now you both speak the same language.

# Start the MCP server

npx @mcpware/ui-annotator

Open in ANY browser

http://localhost:7077/localhost:3847

That's it. No browser extensions. No code changes. No setup. Works in Chrome, Firefox, Safari, Edge — any browser.

How It Works

Your app (localhost:3847)

│ ▼ ┌─────────────────────┐ │ UI Annotator Proxy │ ← Reverse proxy on port 7077 │ (MCP Server) │ └─────────────────────┘ │ ▼ Proxied page with hover annotations injected │ ├──► User sees: hover overlay + tooltip with element names └──► AI sees: structured element data via MCP tools

The proxy fetches your page, injects a lightweight annotation script, and serves it back. The script scans the DOM, identifies named elements, and reports them to the MCP server. Your AI assistant queries the server to understand what's on the page.

Features

Hover Annotations

Hover any element to see:

Element name (pink) — the human-readable identifier
CSS selector (monospace) — the technical reference
Content preview — what text the element contains
Dimensions — width × height in pixels

Inspect Mode

Click the Inspect button in the toolbar (or let your AI toggle it). In inspect mode:

Click any element → copies its name to clipboard
All page interactions are paused (clicks don't trigger buttons/links)
Click Inspect again to return to normal mode

Collapsible Toolbar

The toolbar sits at the top center of the page showing:

Inspect toggle button
Element count
Helpful subtitle explaining what to do
Collapse button (▲) to minimize when not needed

MCP Tools for AI

Tool	What it does
`annotate(url)`	Returns proxy URL for user to open in any browser
`get_elements()`	Returns all detected UI elements with names, selectors, positions
`highlight_element(name)`	Flash-highlights a specific element so user can confirm
`rescan_elements()`	Force DOM rescan after page changes
`inspect_mode(enabled)`	Toggle inspect mode remotely

Why Not Just Use DevTools?

	Browser DevTools	UI Annotator
Target user	Frontend developers who know the DOM	Anyone — QA, PM, designer, junior dev
Learning curve	Need to understand DOM tree, CSS selectors, box model	Hover and read — zero learning
Communication	"The `div.flex.gap-4` inside the second child of..."	"The `sidebar`"
Language	CSS/HTML technical terms	Human-readable names
Setup	Teach people to open DevTools + navigate the DOM	Open a URL
AI integration	None — AI can't see what you're inspecting	MCP — AI sees the same element names you do

DevTools is for debugging. UI Annotator is for communication — giving humans and AI a shared vocabulary for UI elements.

Why Not Use Existing Tools?

None of these do what UI Annotator does — live visual labels on every element via reverse proxy:

Tool	Approach	Why we're different
browser-use (82K⭐)	AI automation framework	Automates browsers, doesn't label elements for humans. Different use case entirely.
Chrome DevTools MCP (31K⭐)	DOM snapshot + element UIDs	AI can inspect, but humans don't see visual annotations. No shared vocabulary.
Playwright MCP (29K⭐)	Accessibility tree snapshot	Returns structured text, no visual overlay. Truncates important context.
OmniParser	Screenshot + CV detection	Screenshot-based, not live DOM. ~40% accuracy on hard benchmarks.
MCP Pointer (526 users)	Chrome extension + MCP	Requires Chrome extension. Human clicks to select — no hover overlay.
Agentation	npm embedded in your app	Requires code changes. React 18+ dependency. Not zero-config.
Vibe Annotations	Chrome extension	Extension-based, developer-only annotation workflow.

Feature Comparison

Feature	UI Annotator	MCP Pointer	Agentation	Cursor	Chrome DevTools MCP
Visual hover annotation	Yes	No	Partial	Yes (IDE only)	No
Shows element names	Yes	Yes	Yes	No (high-level)	Programmatic
Shows dimensions	Yes	Yes	Yes (Detailed)	Yes	Programmatic
MCP server	Yes	Yes	Yes	No	Yes
Zero browser extensions	Yes	No	Yes	N/A	No
Zero code changes	Yes	Yes	No	N/A	Yes
Any browser	Yes	Chrome only	Desktop only	Cursor only	Chrome only
Zero dependencies	Yes	Chrome ext	React 18+	Cursor	Chrome
Click to copy element name	Yes	No	No	No	No

Architecture

Zero external dependencies

Reverse proxy: Node.js built-in http module
MCP server: @modelcontextprotocol/sdk (stdio transport)
Communication: HTTP POST (browser → server) + GET polling (server → browser)
No WebSocket, no Express, no browser extension

How the proxy works

User requests localhost:7077/localhost:3847
Proxy fetches http://localhost:3847
For HTML responses:

Injects fetch() / XMLHttpRequest interceptor (rewrites API paths through proxy)
Rewrites href="/..." and src="/..." attributes to route through proxy
Injects annotation script before

For non-HTML (CSS, JS, images): passes through directly
Strips Content-Security-Policy headers to allow injected script

How annotation works

Script scans DOM for elements with id, class, semantic roles, or interactive roles
On hover: positions overlay border (follows border-radius) + positions tooltip (always within viewport)
Reports all detected elements to server via POST /__annotator/elements
Polls GET /__annotator/commands every second for server instructions (highlight, rescan, inspect toggle)
MutationObserver auto-rescans when DOM changes

Quick Start

With Claude Code

# Add as MCP server

claude mcp add ui-annotator -- npx @mcpware/ui-annotator

Then in conversation:

"Annotate my app at localhost:3847"

→ AI returns proxy URL, you open it, hover elements, discuss changes by name

Manual

npx @mcpware/ui-annotator

Proxy starts on http://localhost:7077

Open http://localhost:7077/localhost:YOUR_PORT

Environment Variables

Variable	Default	Description
`UI_ANNOTATOR_PORT`	`7077`	Port for the proxy server

More from @mcpware

Project	What it does	Install
[Instagram MCP](https://github.com/mcpware/instagram-mcp)	23 Instagram Graph API tools — posts, comments, DMs, stories, analytics	`npx @mcpware/instagram-mcp`
[Claude Code Organizer](https://github.com/mcpware/claude-code-organizer)	Visual dashboard for Claude Code memories, skills, MCP servers, hooks	`npx @mcpware/claude-code-organizer`
[Pagecast](https://github.com/mcpware/pagecast)	Record browser sessions as GIF or video via MCP	`npx @mcpware/pagecast`
[LogoLoom](https://github.com/mcpware/logoloom)	AI logo design → SVG → full brand kit export	`npx @mcpware/logoloom`

License

MIT

UI Annotator MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Web & browsersi

Common questions

Alternatives

Browser Use

Chrome DevTools MCP

MCP Server Browser

README from the maker

UI Annotator MCP

Why It Matters

The Problem

The Solution

Open in ANY browser

How It Works

Features

Hover Annotations

Inspect Mode

Collapsible Toolbar

MCP Tools for AI

Why Not Just Use DevTools?

Why Not Use Existing Tools?

Feature Comparison

Architecture

Zero external dependencies

How the proxy works

How annotation works

Quick Start

With Claude Code

Then in conversation:

"Annotate my app at localhost:3847"

→ AI returns proxy URL, you open it, hover elements, discuss changes by name

Manual

Proxy starts on http://localhost:7077

Open http://localhost:7077/localhost:YOUR_PORT

Environment Variables

More from @mcpware

License