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CDP MCP

A Chrome DevTools Protocol MCP server for browser automation. Built for agents that need to fill forms, navigate sites, and remember what they learn.

Why This Exists

Most browser automation MCPs are either:

  • Wrappers around heavyweight frameworks (Playwright, Puppeteer)

  • Locked to specific sites

  • Missing element discovery (you have to guess selectors)

CDP MCP talks directly to Chrome via the DevTools Protocol. It auto-discovers interactive elements, generates selectors for you, and verifies that interactions actually worked.

Installation

npm install npm run build

Usage

Add to your Claude Code MCP config (~/.claude.json):

{ "mcpServers": { "cdp": { "type": "stdio", "command": "node", "args": ["/path/to/cdp-mcp/dist/index.js"] } } }

Then either:

  1. Launch Chrome with CDP enabled: cdp_launch

  2. Or connect to an existing Chrome with --remote-debugging-port=9222: cdp_connect

Tools

Tool

Purpose

cdp_launch

Launch Chrome with CDP enabled, isolated profile

cdp_connect

Connect to existing Chrome instance

cdp_list_tabs

List all open tabs

cdp_navigate

Go to URL, back, forward, refresh

cdp_find_elements

Discover all interactive elements with auto-generated selectors

cdp_interact

Click, type, check, select, upload - with built-in verification

cdp_read

Read page text, element text, input values

cdp_screenshot

Capture viewport or full page

cdp_wait

Wait for element, text, navigation

cdp_execute

Run arbitrary JavaScript (escape hatch)

cdp_list_frames

List all frames (main + iframes)

cdp_frame_interact

Interact with elements inside iframes

cdp_type_text

Type at cursor position (for React/Vue/Angular)

cdp_click_coordinates

Click at x,y coordinates

cdp_set_value

Set input value with proper event dispatch

cdp_monaco_editor

Interact with Monaco/VS Code editors

cdp_upload_shadow

Upload files to shadow DOM file inputs

cdp_submit_form

Submit forms reliably (React/Vue/Angular compatible)

Site Memory Tools

Tool

Purpose

cdp_site_scan

Scan page structure (iframes, shadow DOM, forms) - auto-caches per epoch

cdp_site_info

Get stored site info for current page or domain

cdp_site_note

Add notes or selector patterns you learn

cdp_site_list

List all remembered sites

cdp_site_clear

Forget a site (force fresh scan)

cdp_epoch_info

Debug epoch tracking

Bug Tracking Tools

Tool

Purpose

cdp_track_bug

Track a bug in CDP-MCP (writes to BUGS.md)

cdp_list_bugs

List all tracked bugs

cdp_fix_bug

Mark a bug as fixed and remove it

Key Features

Auto-Discovery

cdp_find_elements returns every interactive element on the page with:

  • Tag, type, id, name, class

  • Associated label (from <label>, aria-label, etc.)

  • Auto-generated CSS selector

  • Visibility and position

No more guessing selectors or inspecting the DOM manually.

Built-in Verification

cdp_interact verifies that actions actually worked:

{ "success": true, "action": "type", "selector": "#email", "expected": "user@example.com", "actual": "user@example.com", "verified": true }

If a React controlled input silently rejects your value, you'll know immediately.

Site Memory

The MCP remembers what it learns about sites:

  • Iframe locations - Which sites use iframes and where

  • Shadow DOM elements - Components that need special handling

  • Selector patterns - CSS selectors that work for common actions

  • Notes - Context you add while working

Stored in ~/.claude/site-memory.json, persists across sessions.

Epoch Tracking

Site memory integrates with Claude Code's conversation compaction:

  1. First visit to a site → full scan, cache results

  2. Same site later in conversation → skip scan, use cache

  3. After conversation compaction → allow one fresh scan (you lost context)

  4. Back to caching until next compaction

This prevents redundant scanning while ensuring you re-orient after context loss.

Minimal Dependencies

  • ws - WebSocket client for CDP

  • That's it

No Playwright. No Puppeteer. Just raw CDP over WebSocket.

Example Workflow

1. cdp_connect → Connect to Chrome on port 9222 2. cdp_navigate → Go to a form page 3. cdp_find_elements → Get all inputs with selectors 4. cdp_interact (type) → Fill fields, get verification 5. cdp_interact (click) → Submit 6. cdp_wait (navigation) → Wait for redirect 7. cdp_read → Confirm success

Design Philosophy

  • Focused tool set - Everything an agent needs for browser automation

  • CSS selectors - Universal, inspectable, copy-pasteable

  • Verification by default - Know if it worked without extra calls

  • cdp_execute - When you need raw JS, it's there

Requirements

  • Node.js 18+

  • Chrome/Chromium with --remote-debugging-port flag

License

MIT

-
security - not tested
F
license - not found
-
quality - not tested

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