Borrowing it
Nothing to install: this file belongs to triuzzi/brave-devtools-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.
curl -O https://raw.githubusercontent.com/triuzzi/brave-devtools-mcp/main/AGENTS.mdgit clone --depth 1 https://github.com/triuzzi/brave-devtools-mcpWrote 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.
[](https://agentmods.dev/instructions/triuzzi/brave-devtools-mcp/agents-md)<a href="https://agentmods.dev/instructions/triuzzi/brave-devtools-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/triuzzi/brave-devtools-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.
<a href="https://agentmods.dev/instructions/triuzzi/brave-devtools-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/triuzzi/brave-devtools-mcp/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00971 | $0.00971 |
| Opus 5.5 | $0.00388 | $0.00388 |
| Sonnet 5.5 | $0.00194 | $0.00194 |
| Haiku 4.5 | $0.00097 | $0.00097 |
Grade A, and why
brave-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 1mo 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.
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.
This is a copy
100% identical to chrome-devtools-mcp AGENTS.md — 157 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
This repository contains an MCP server and CLI for Chrome DevTools.
Instructions
- Use only scripts from
package.jsonto run commands. - Use
npm run buildto run tsc and test build. - Use
npm run testto build and run tests, run all tests to verify correctness. - Use
npm run test path-to-test.tsto build and run a single test file, for example,npm run test tests/McpContext.test.ts. - Use
npm run formatto fix formatting and get linting errors. - Never modify
third_party/devtools-frontendexcept for experimentation: it is a git submodule, a mirror of the actual codebase.
Rules for TypeScript
- Do not use
anytype. - Do not use
askeyword for type casting. - Do not use
!operator for type assertion. - Do not use
// @ts-ignorecomments. - Do not use
// @ts-nocheckcomments. - Do not use
// @ts-expect-errorcomments. - Prefer
for..ofinstead offorEach. - Never type-check types that are already type safe (e.g. redundant
typeofchecks on statically typed variables).
Rules for Testing
Structure and Separation of Concerns
- Prefer mock-based unit tests over real-browser tests: Do not use
withMcpContextor launch a real browser unless the test genuinely requires real browser or DevTools protocol integration (e.g., live CDP events, browser lifecycle, secondary sessions). Puppeteer already tests browser behavior upstream; unit tests run faster and avoid browser overhead. - Tool handler tests (
tests/tools/*.test.ts):- Test that the tool handler parses/validates parameters and invokes the corresponding methods on
page,context, orresponsewith the exact expected arguments. - Do not reimplement business logic or state tracking inside mocks (e.g., do not simulate state changes in mock methods).
- Test that the tool handler parses/validates parameters and invokes the corresponding methods on
- Core class tests (e.g.,
tests/McpPage.test.ts):- Test business logic by instantiating the real class under test with mocked dependencies (e.g., instantiate
new McpPage(...)with a mocked Puppeteer page fromcreateMockPuppeteerPage()). - Assert that the class calls the underlying Puppeteer methods with the expected parameters.
- Test business logic by instantiating the real class under test with mocked dependencies (e.g., instantiate
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.
- 1mo ago Changed · +37 lines · +735 tokens per session 1b804c2b806a
- 1mo ago First seen · 21 lines · 236 tokens per session scan A 9087ba513381
brave-devtools-mcp AGENTS.md is an instructions file published in the GitHub repository triuzzi/brave-devtools-mcp (44 stars, last pushed 4d ago), licensed Apache-2.0. It adds 971 tokens to every session, about $0.0039 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to chrome-devtools-mcp AGENTS.md, differing in 157 lines, and is treated as a copy.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.