mustel: Cursor rule for Windsurf

.windsurfrules

windsurfrules is a cursor rule for Windsurf from mustel-py/mustel. It costs 79 tokens per session, scanned A, a copy of cursorrules, MIT.

A coding rule that requires an agent to run a separate review tool before proposing or finalizing code changes. The review checks syntax, bugs, standards, and security issues.

In plain words
What is it for?
Use it to enforce a project-specific code-review and security check in an agent's coding workflow.
Why use it?
It adds a required review step before code is shown to the user. It also tells the agent to fix reported problems and security vulnerabilities first.

Cursor rule for Windsurf

Written for Windsurf: a Windsurf rule.

This is mustel-py/mustel's own configuration. It tells Windsurf how to work on mustel itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mustel configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mustel-py/mustel. 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/mustel-py/mustel/main/.windsurfrules
Clone the repo
git clone --depth 1 https://github.com/mustel-py/mustel

Made for: Windsurf.

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.

agentmods badge for windsurfrules

README.md
[![agentmods](https://agentmods.dev/badge/rules/mustel-py/mustel/windsurfrules/github.svg)](https://agentmods.dev/rules/mustel-py/mustel/windsurfrules)
Your own site
<a href="https://agentmods.dev/rules/mustel-py/mustel/windsurfrules"><img src="https://agentmods.dev/badge/rules/mustel-py/mustel/windsurfrules/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.

agentmods 80×15 button for windsurfrules

Your own site · 80×15
<a href="https://agentmods.dev/rules/mustel-py/mustel/windsurfrules"><img src="https://agentmods.dev/badge/rules/mustel-py/mustel/windsurfrules.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 79 This file is loaded in full into every session.
When invoked 79 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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 5.1 $0.00079 $0.00079
Opus 5.5 $0.00032 $0.00032
Sonnet 5.5 $0.00016 $0.00016
Haiku 4.5 $0.00008 $0.00008

Measured 2d ago against content hash ddd8d1ded842, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

windsurfrules 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 2d 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.

Origin

This is a copy

100% identical to cursorrules — 0 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.

.windsurfrules · 8 lines

What it actually says

--- MUSTEL AGENT GUARDRAILS ---

Before proposing or finalizing code changes, you must run the mustel review tool.

Call the review or review_file MCP tool to verify syntax, bugs, and standards.

Fix all reported errors and security vulnerabilities before showing changes to the user.

--- END MUSTEL AGENT GUARDRAILS ---

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. 2d ago First seen · 8 lines · 79 tokens per session scan A ddd8d1ded842

Subscribe to this mod's changes

windsurfrules is a cursor rule published in the GitHub repository mustel-py/mustel (19 stars, last pushed 3d ago), licensed MIT. It adds 79 tokens to every session, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to cursorrules, differing in 0 lines, and is treated as a copy.