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 rules/oguzhankir/fmtly/cursorrulesgit clone --depth 1 https://github.com/oguzhankir/fmtlyWhat 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 | $0.01066 | $0.01066 |
| Opus 5 | $0.00533 | $0.00533 |
| Sonnet 5 | $0.00213 | $0.00213 |
| Haiku 4.5 | $0.00107 | $0.00107 |
Grade A, and why
cursorrules 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.
How it starts
The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.
fmtly — Windsurf Rules
Read this file entirely before writing any code.
The Vision
Format, validate, convert, and diff structured data. No login. No server. Instant.
fmtly is not just a random collection of utilities. It is a deep, focused platform for structured data formats (JSON, XML, YAML, CSV, TOML), with a visionary roadmap to expand into AI/LLM toolchains, encoders, code formatters, and more.
The Golden Rule: Every tool runs in the browser. No user data ever touches a server. Exception: Network tools (IP lookup, DNS, etc.) proxy through a minimal Cloudflare Worker without logging.
Stack
- SvelteKit 2 + TypeScript 5 + Tailwind CSS 4
- Cloudflare Pages (static) + Cloudflare Workers (network proxy only)
- Package manager: pnpm — never npm, never yarn
- Adapter:
@sveltejs/adapter-cloudflare
Architecture Rules
Tool Registry
Every tool is a config object in src/lib/registry/tools/[category].tools.ts.
Never create a route file for a tool — register it, the page generates itself.
Category-Based Structure
When adding new tools or categories, strictly adhere to the category-based folder structure:
- Registry:
src/lib/registry/tools/[category].tools.ts - Engines:
src/lib/engines/[category]/(include anindex.tsbarrel file) - Panels:
src/lib/components/panels/[category]/ - Tests:
tests/unit/[category]/ - Stores:
src/lib/stores/[category].store.ts(if state is required) - Locales:
src/lib/i18n/registry/[lang].ts
Never put category-specific logic in shared directories.
Lazy Loading — No Exceptions
Every processing library uses dynamic import(). Never at top level.
This applies to: ajv, js-yaml, fast-xml-parser, smol-toml, @wasm-fmt/taplo_fmt, Monaco Editor, etc.
If it processes data → dynamic import.
No Backend for User Data
Permitted server-side code only:
+page.tsload functions (read registry)/sitemap.xml/+server.ts(build time only)
Static Output Only
No Node.js APIs in browser code (fs, path, crypto module — use Web Crypto API).
No env vars in browser except PUBLIC_ prefix.
Never delete static/_headers, static/_redirects, static/_routes.json.
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.
- yesterday First seen · 124 lines · 1,066 tokens per session scan A 691884928e6d
cursorrules is a cursor rule published in the GitHub repository oguzhankir/fmtly (4 stars, last pushed 2mo ago), licensed MIT. It adds 1,066 tokens to every session, about $0.0053 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 cursor rules, from other repositories
docs
All documentation files use MDX format with a specific structure.
tutorial-system-guide
This guide documents the complete tutorial infrastructure in Windmill's frontend, enabling developers to create new interactive tutorials without re-exploring the codebase.
windmill-overview
Windmill is an open-source developer platform for building internal tools, API integrations, background jobs, workflows, and user interfaces. It offers a unified system where scripts are automatically turned into sharable UIs and can be composed into flows or embedded in custom applications.
cursorrules
Read and follow AGENTS.md for all development conventions.
mcp-readme
The Model Context Protocol allows applications to provide context for LLMs in a standardized way, separating the concerns of providing context from the actual LLM interaction. This TypeScript SDK implements the full MCP specification, making it easy to.
typescript
Cursor rule "typescript" from Novalya-Labs/plane-mcp-server, covering typescript best practices, type system, naming conventions, code organization and functions.