Borrowing it
Nothing to install: this file belongs to adityasasidhar/browsercontrol. 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/adityasasidhar/browsercontrol/main/AGENTS.mdgit clone --depth 1 https://github.com/adityasasidhar/browsercontrolWrote 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/adityasasidhar/browsercontrol/agents-md)<a href="https://agentmods.dev/instructions/adityasasidhar/browsercontrol/agents-md"><img src="https://agentmods.dev/badge/instructions/adityasasidhar/browsercontrol/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/adityasasidhar/browsercontrol/agents-md"><img src="https://agentmods.dev/badge/instructions/adityasasidhar/browsercontrol/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 | $0.00772 | $0.00772 |
| Opus 5.5 | $0.00309 | $0.00309 |
| Sonnet 5.5 | $0.00154 | $0.00154 |
| Haiku 4.5 | $0.00077 | $0.00077 |
Grade A, and why
browsercontrol 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 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.
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.
How it starts
The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Repository Guidelines
Project Structure & Module Organization
browsercontrol/contains the Python package.server.pycomposes the FastMCP server and registers tool groups;browser.pyowns the Playwright browser lifecycle and Set-of-Marks state;config.pyreads environment configuration.browsercontrol/tools/groups MCP tools by capability (navigation.py,interaction.py,forms.py,content.py,devtools.py,recording.py, andtabs.py).tests/contains pytest tests and shared mocked Playwright fixtures inconftest.py; keep module tests in matchingtest_<module>.pyfiles.docs/is the MkDocs Material documentation site; images and other static assets live inassets/anddocs/assets/.
Build, Test, and Development Commands
Use Python 3.11+ and uv for all project commands:
uv sync
uv run playwright install chromium
uv run fastmcp dev browsercontrol/server.py
uv run pytest tests/test_navigation.py
uv run pytest
uv run mkdocs build --strict
The focused pytest command is useful while iterating; the full suite uses mocks and normally does not launch Chromium. Run the development server through FastMCP's inspector UI.
Coding Style & Naming Conventions
Use four-space Python indentation, double quotes, and a 100-character Ruff target. Prefer explicit type annotations: mypy runs in strict mode. Name modules and functions in snake_case, classes in PascalCase, and tests test_<behavior>. Keep tool docstrings actionable because FastMCP exposes them to clients.
Before submitting code, run:
uv run pre-commit run --all-files
uv run ruff check .
uv run ruff format --check .
uv run mypy browsercontrol/
uv run bandit -c pyproject.toml -r . --exclude ./tests,./.venv
Testing & Tool Changes
Cover both success and graceful-error paths. Tool tests should register against a throwaway FastMCP instance and patch the tool module's imported browser. New browser-changing tools should call await browser.ensure_started() and return a fresh annotated screenshot with an element summary. Element IDs are valid only for the latest screenshot.
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 · 52 lines · 772 tokens per session scan A 5080ee79a5e6
browsercontrol AGENTS.md is an instructions file published in the GitHub repository adityasasidhar/browsercontrol (12 stars, last pushed 1mo ago), licensed MIT. It adds 772 tokens to every session, about $0.0031 per session on Opus 5.5. 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.
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