astro

A set of coding guidelines for Astro websites, a web framework aimed mainly at content-heavy sites such as blogs, documentation, and marketing pages. It uses small interactive sections, called islands, only where a page needs them.

In plain words
What is it for?
Use it when building or reviewing Astro blogs, documentation sites, and other content-focused websites with optional React, Vue, or Svelte interactions.
Why use it?
It encourages sending little or no JavaScript to the browser by default while still allowing selected interactive components. It also defines patterns for content collections, routing, layouts, and components.

Cursor rule

Install

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.

agentmods
npx agentmods add rules/renvia-code/best-cursor-rules/astro
Clone the repo
git clone --depth 1 https://github.com/Renvia-code/best-cursor-rules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,729 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00000 $0.01729
Opus 5 $0.00000 $0.00864
Sonnet 5 $0.00000 $0.00346
Haiku 4.5 $0.00000 $0.00173

Measured yesterday against content hash 45513ebbe7a9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

astro 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.

rules/frameworks/astro.mdc · 369 lines

How it starts

The opening of the file, as written. The whole thing — 369 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Astro Best Practices

Overview

Aspect Recommendation
Use Case Content-focused sites, blogs, docs
Default Zero JS shipped to client
Interactive Islands (React, Vue, Svelte, etc.)
Content Content Collections

Project Structure

src/
├── components/     # .astro and framework components
├── content/        # Content collections (markdown, MDX)
│   └── blog/
│       └── post-1.md
├── layouts/        # Page layouts
├── pages/          # File-based routing
│   ├── index.astro
│   └── blog/
│       └── [slug].astro
├── styles/         # Global styles
└── content.config.ts  # Collection schemas

Astro Components

Basic Component

---
// Component Script (runs at build time)
interface Props {
  title: string
  description?: string
}

const { title, description = 'Default description' } = Astro.props
const currentYear = new Date().getFullYear()
---

<!-- Component Template -->
<article>
  <h1>{title}</h1>
  <p>{description}</p>
  <footer>© {currentYear}</footer>
</article>

<style>
  /* Scoped by default */
  article {
    padding: 1rem;
  }
</style>

Slots

---
// Card.astro
interface Props {
  title: string
}

const { title } = Astro.props
---

<div class="card">
  <h2>{title}</h2>
  <slot />  <!-- Default slot -->
  <slot name="footer" />  <!-- Named slot -->
</div>

<!-- Usage -->
<Card title="My Card">
  <p>Card content</p>
  <div slot="footer">Footer content</div>
</Card>

Islands Architecture

Client Directives

---
import ReactCounter from './Counter.tsx'
import VueModal from './Modal.vue'
---

<!-- Load immediately -->
<ReactCounter client:load />

<!-- Load when visible (lazy) -->
<ReactCounter client:visible />

<!-- Load when idle -->
<ReactCounter client:idle />

<!-- Load on specific media query -->
<VueModal client:media="(max-width: 768px)" />

<!-- Only hydrate client-side (no SSR) -->
<ReactCounter client:only="react" />

Read the full file on GitHub · 369 lines

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. yesterday First seen · 369 lines · 0 tokens per session scan A 45513ebbe7a9

Subscribe to this mod's changes

astro is a cursor rule published in the GitHub repository Renvia-code/best-cursor-rules (12 stars, last pushed 9mo ago), licensed CC0-1.0. It costs nothing until one of its globs matches a file; then it loads 1,729 tokens. 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 2026-08-30.