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.
npx agentmods add instructions/derailed-dash/browsermcp-ext/gemini-mdgit clone --depth 1 https://github.com/derailed-dash/browsermcp-extWrote 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/derailed-dash/browsermcp-ext/gemini-md)<a href="https://agentmods.dev/instructions/derailed-dash/browsermcp-ext/gemini-md"><img src="https://agentmods.dev/badge/instructions/derailed-dash/browsermcp-ext/gemini-md.svg" alt="Measured on agentmods" 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 | $0.00176 | $0.00176 |
| Opus 5 | $0.00088 | $0.00088 |
| Sonnet 5 | $0.00035 | $0.00035 |
| Haiku 4.5 | $0.00018 | $0.00018 |
Grade A, and why
browsermcp-ext GEMINI.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 5d 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.
What it actually says
BrowserMCP Agent Instructions
This extension provides tools to interact with a web browser using BrowserMCP.
Capabilities
- Navigate to URLs
- Inspect the DOM
- Click buttons and type text into forms
- Read browser console logs
Limitations
- It requires an existing Chrome or Chromium-based browser session with the BrowserMCP extension installed and connected.
- It cannot spawn new sessions.
- It cannot work with the local file system (e.g., cannot save screenshots to local disk).
- It is not "headless" and requires a visible browser window.
Usage
When asked to perform tasks on a web page, use the available BrowserMCP tools.
Remember that for these tools to work, the user must first install the BrowserMCP Chrome extension, navigate to the target page, and click "Connect" in the extension popup.
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.
- 5d ago First seen · 24 lines · 176 tokens per session scan A 1cf1c4f3468f
browsermcp-ext GEMINI.md is an instructions file published in the GitHub repository derailed-dash/browsermcp-ext (2 stars, last pushed 5mo ago), licensed MIT. It adds 176 tokens to every session, about $0.0009 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 2026-08-31.
Other instructions, from other repositories
flyto-core AGENTS.md
AGENTS.md instructions for flytohub/flyto-core, covering flyto-core agent rules, flyto2 project memory contract, flyto2 frontend quality gate and repo notes.
apitap CLAUDE.md
Instructions for n1byn1kt/apitap, covering claude.md, using apitap as an mcp tool, commands, architecture and module map.
web-developer-mcp CLAUDE.md
Instructions for Artmann/web-developer-mcp, covering claude instructions for webdev mcp server, development guidelines, code style & organization, project structure and browser management.
qa-use CLAUDE.md
Instructions for desplega-ai/qa-use, covering claude.md, project map and tech stack.
gemini-extension GEMINI.md
Instructions for conversiontools/gemini-extension, covering conversion tools, if the tools are not available, how to convert a file, build a custom converter (ai studio) and tip: prefer the ctio cli when available.
pinchtab-mcp AGENTS.md
AGENTS.md instructions for maderwin/pinchtab-mcp, covering agent guidelines for pinchtab-mcp, key decisions (non-obvious), recommended workflow, when modifying tools and related projects.