What is chrome-local-mcp AGENTS.md?

Instructions for chrome-local-mcp, an MCP server that connects an assistant to a Windows Chrome browser through Chrome's developer connection. It supports WSL setups and keeps people involved for CAPTCHAs and verification challenges.

Setting up, testing, and registering chrome-local-mcp with Codex or the Codex command line.

They document the required Chrome startup option, build and test commands, and registration steps needed to make the browser connection available.

How thronapple/chrome-local-mcp configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to thronapple/chrome-local-mcp. 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/thronapple/chrome-local-mcp/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/thronapple/chrome-local-mcp

Made for: Codex, OpenCode.

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/thronapple/chrome-local-mcp/agents-md/github.svg)](https://agentmods.dev/instructions/thronapple/chrome-local-mcp/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/thronapple/chrome-local-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/thronapple/chrome-local-mcp/agents-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/thronapple/chrome-local-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/thronapple/chrome-local-mcp/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 714 This file is loaded in full into every session.

When invoked 714 The same file — it is already loaded in full.

Security scan B 2 findings. 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	$0.00714	$0.00714
Opus 5.5	$0.00286	$0.00286
Sonnet 5.5	$0.00143	$0.00143
Haiku 4.5	$0.00071	$0.00071

Measured 2mo ago against content hash 974c64fa8a0a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

chrome-local-mcp AGENTS.md scanned grade B with 2 findings 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

Edit `~/.codex/config.toml`:

Makes network callslowCapability

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

curl http://localhost:9222/json/version # Verify Chrome CDP is reachable

AGENTS.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

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

Project Overview

chrome-local-mcp is a lightweight MCP (Model Context Protocol) server that connects to a Windows Chrome instance via CDP (Chrome DevTools Protocol). Designed for WSL environments where Codex needs to control a real browser with human-in-the-loop support for CAPTCHAs and verification challenges.

Build & Run

npm run build          # Compile TypeScript → dist/
npm run dev            # Watch mode
npm start              # Run the MCP server (requires Chrome with --remote-debugging-port=9222)

Register with Codex

Codex mcp add --scope user chrome-local -- node /mnt/d/repository/chrome-local-mcp/dist/index.js

Register with Codex CLI

Edit ~/.codex/config.toml:

[mcp_servers.chrome-local]
command = ["node", "/mnt/d/repository/chrome-local-mcp/dist/index.js"]

Test

npm test                           # Quick tool listing test
curl http://localhost:9222/json/version  # Verify Chrome CDP is reachable

Prerequisites

Windows Chrome must be running with remote debugging:

chrome.exe --remote-debugging-port=9222

Architecture

Codex (WSL) → stdio → MCP Server (WSL/Node.js) → CDP WebSocket → Chrome (Windows)

Transport: stdio (MCP standard for CLI agents)
CDP connection: chrome-remote-interface npm package, single persistent connection with auto-reconnect
Token strategy: Long content saved to temp files (/tmp/chrome-mcp/), only summaries returned to LLM context

Source Structure

src/index.ts — Entry point, CLI arg parsing, server bootstrap
src/cdp.ts — CDP connection management (connect, reconnect, target switching)
src/detect.ts — Shared challenge auto-detection (Cloudflare, CAPTCHA, login walls, etc.)
src/tools/navigation.ts — navigate, wait_for, go_back
src/tools/content.ts — get_content (smart extraction), evaluate (JS exec), screenshot
src/tools/interaction.ts — click, fill, press_key, scroll
src/tools/tabs.ts — tab_list, tab_open, tab_switch, tab_close
src/tools/search.ts — Google search with auto CAPTCHA detection
src/tools/human.ts — wait_for_human, check_page_status
src/types/chrome-remote-interface.d.ts — Type declarations for CDP client

Read the full file on GitHub · 74 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 · 74 lines · 714 tokens per session scan B 974c64fa8a0a

Subscribe to this mod's changes

chrome-local-mcp AGENTS.md is an instructions file published in the GitHub repository thronapple/chrome-local-mcp (0 stars, last pushed 3mo ago), licensed MIT. It adds 714 tokens to every session, about $0.0029 per session on Opus 5.5. A static security scan graded it B with 2 findings (reads agent configuration directories, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Browser automation browser-automation chrome chrome-devtools-protocol human-in-the-loop mcp

chrome-local-mcp AGENTS.md next to 6 instructions from other repositories
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chrome-local-mcp: Instructions file for Codex