What is browser-mcp-bridge CLAUDE.md?

A set of instructions for working on a browser bridge that sends browser data to Claude Code through MCP, a standard way for programs to share tools and information. It covers the browser extension, server, architecture and development commands.

Use it when developing the browser extension or Node.js server, working with browser tabs, or changing the WebSocket communication and MCP tools.

It gives the coding agent the project context needed to understand how browser data moves between the extension and server. This reduces guesswork when changing or debugging the system.

How robhicks/browser-mcp-bridge configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to robhicks/browser-mcp-bridge. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/robhicks/browser-mcp-bridge/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/robhicks/browser-mcp-bridge

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/robhicks/browser-mcp-bridge/claude-md/github.svg)](https://agentmods.dev/instructions/robhicks/browser-mcp-bridge/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/robhicks/browser-mcp-bridge/claude-md"><img src="https://agentmods.dev/badge/instructions/robhicks/browser-mcp-bridge/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/robhicks/browser-mcp-bridge/claude-md"><img src="https://agentmods.dev/badge/instructions/robhicks/browser-mcp-bridge/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,684 This file is loaded in full into every session.

When invoked 1,684 The same file — it is already loaded in full.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01684	$0.01684
Opus 5.5	$0.00674	$0.00674
Sonnet 5.5	$0.00337	$0.00337
Haiku 4.5	$0.00168	$0.00168

Measured 2mo ago against content hash 8e323294e820, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

browser-mcp-bridge CLAUDE.md scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

# or: curl http://localhost:6009/health

CLAUDE.md · 226 lines

How it starts

The opening of the file, as written. The whole thing — 226 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Architecture

This is a Browser MCP Bridge - a two-part system that connects browser extension data with Claude Code through the Model Context Protocol (MCP):

Browser Extension (extension/ directory) - Chrome extension that captures browser data, DOM snapshots, console messages, network activity, and developer tools information
HTTP MCP Server (server/ directory) - Node.js server that exposes browser data to Claude Code through 11 specialized MCP tools and dynamic resources

Core Communication Flow

Extension captures browser data via content scripts, background workers, and DevTools APIs
WebSocket connection (port 6009) bridges extension and MCP server
HTTP MCP Server allows multiple Claude Code instances to connect to the same server
Multi-tab support with tabId-based tool targeting

Key Components

Extension Architecture:

manifest.json - Manifest v3 with extensive permissions (tabs, debugger, scripting, webRequest)
background.js - Service worker handling WebSocket communication and tab management
content.js - Content script for page data extraction and DOM manipulation
inject.js - Injected script for deep page context access
devtools.html/js + panel.html/js - Custom DevTools panel for advanced inspection
popup.html/js - Extension popup for connection management

Server Architecture:

server.js - HTTP MCP server with WebSocket server for browser connections
HTTP Transport: Multiple Claude Code instances can connect to the same server
WebSocket Transport: Browser extensions connect via WebSocket to /ws
Implements 11 MCP tools: get_page_content, get_dom_snapshot, execute_javascript, get_console_messages, get_network_requests, capture_screenshot, get_performance_metrics, get_accessibility_tree, get_browser_tabs, attach_debugger, detach_debugger
Dynamic resources for real-time browser data access
Connection management for multiple browser tabs

Read the full file on GitHub · 226 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 226 lines · 1,684 tokens per session scan A 8e323294e820

Subscribe to this mod's changes

browser-mcp-bridge CLAUDE.md is an instructions file published in the GitHub repository robhicks/browser-mcp-bridge (0 stars, last pushed 7mo ago), licensed MIT. It adds 1,684 tokens to every session, about $0.0067 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

browser-mcp-bridge CLAUDE.md next to 6 instructions from other repositories
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browser-mcp-bridge: Instructions file for Claude Code