agentmods.dev

chrome-devtools-mcp AGENTS.md

Repository guidance for a TypeScript project that provides a server and command-line tool for Chrome DevTools. It records the approved commands, coding rules, and files to leave untouched.

In plain words
What is it for?
Use it when changing this project, especially when building, running tests, formatting code, or editing TypeScript.
Why use it?
It gives a coding agent clear project rules, reducing accidental changes and inconsistent checks.

Instructions file for CodexOpenCode

50k 2d ago A scan 236 tokens original Apache-2.0
View the source file ChromeDevTools/chrome-devtools-mcp
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/chromedevtools/chrome-devtools-mcp/agents-md
Clone the repo
git clone --depth 1 https://github.com/ChromeDevTools/chrome-devtools-mcp

Made for: Codex, OpenCode.

Per session 236 This file is loaded in full into every session.
When invoked 236 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00236 $0.00236
Opus 5 $0.00118 $0.00118
Sonnet 5 $0.00047 $0.00047
Haiku 4.5 $0.00024 $0.00024

Measured yesterday against content hash 9087ba513381, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

chrome-devtools-mcp AGENTS.md scanned grade A with 0 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 yesterday.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

AGENTS.md · 21 lines

What it actually says

This repository contains an MCP server and CLI for Chrome DevTools.

Instructions

  • Use only scripts from package.json to run commands.
  • Use npm run build to run tsc and test build.
  • Use npm run test to build and run tests, run all tests to verify correctness.
  • Use npm run test path-to-test.ts to build and run a single test file, for example, npm run test tests/McpContext.test.ts.
  • Use npm run format to fix formatting and get linting errors.
  • Never modify third_party/devtools-frontend except for experimentation: it is a git submodule, a mirror of the actual codebase.

Rules for TypeScript

  • Do not use any type.
  • Do not use as keyword for type casting.
  • Do not use ! operator for type assertion.
  • Do not use // @ts-ignore comments.
  • Do not use // @ts-nocheck comments.
  • Do not use // @ts-expect-error comments.
  • Prefer for..of instead of forEach.
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.

  1. yesterday First seen · 21 lines · 236 tokens per session scan A 9087ba513381

Subscribe to this mod's changes

chrome-devtools-mcp AGENTS.md is an instructions file published in the GitHub repository ChromeDevTools/chrome-devtools-mcp (50,208 stars, last pushed 2d ago), licensed Apache-2.0. It adds 236 tokens to every session, about $0.0012 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Browser automationDebuggingTestingchromechrome-devtoolsmcp-serverpuppeteer
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