Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/ericrisco/rsc-harnessnpx agentmods add skills/ericrisco/rsc-harness/astroWrote 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/skills/ericrisco/rsc-harness/astro)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/astro"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/astro.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 | $0.00067 | $0.03125 |
| Opus 5 | $0.00034 | $0.01563 |
| Sonnet 5 | $0.00013 | $0.00625 |
| Haiku 4.5 | $0.00007 | $0.00313 |
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 6d 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 — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Astro 6 — static-first sites, islands, content collections
The prime directive
Ship zero client JavaScript by default. Hydrate the smallest possible surface, as late as you can
get away with. An .astro component renders to HTML at build time and ships no runtime; every
island is a bundle the visitor downloads, parses, and executes. Content and marketing sites win on
TTFB/LCP and Lighthouse, not on React-everywhere. If you find yourself adding client:load to make
a page "work," stop — the page already works; you are adding interactivity, and interactivity is the
expensive exception, not the default.
First: detect the project version
Astro 6.0 is stable (released 2026-03-10); the Astro 5 line is
still production-ready. Do not mix advice across majors — read package.json → the astro version
before advising. What v6 changes, per the
upgrade-to-v6 guide:
- Node
22.12.0or higher is required (18 and 20 are dropped) — check the actual runtime. - Content config lives at
src/content.config.ts. The legacysrc/content/config.tspath is removed, not merely discouraged, and the old auto-detection (legacy.collections) is gone. Thelegacy.collectionsBackwardsCompatescape hatch is a migration crutch, not a supported layout. - Vite 7 and Zod 4 for content schemas —
zis imported fromastro/zod, notastro:content(see Content collections below). - Live Content Collections, the Fonts API and the CSP API are stable.
- The Rust compiler succeeding the Go one is experimental — do not rely on or configure it in production advice.
Decision table — what kind of thing is this?
Pick the cheapest row that satisfies the requirement. Read top-down; stop at the first match.
| Need | Use | Why |
|---|---|---|
| Pure content, no interactivity | .astro component, static |
Renders to HTML at build, ships 0 KB JS |
| One small interactive widget | UI-framework component + client:* |
Hydrate just that island; the rest stays static |
| Per-request personalization on a mostly-static page | server island (server:defer) |
Static CDN page + one deferred fragment, no full SSR |
| Whole route needs request data on every load | export const prerender = false + adapter |
Opt that one route into on-demand rendering |
| Many static routes generated from data | getStaticPaths() |
Build-time fan-out, still fully static |
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 6d ago First seen · 258 lines · 67 tokens per session scan A 806f0556ccd1
astro is a skill published in the GitHub repository ericrisco/rsc-harness (65 stars, last pushed today), licensed MIT. It adds 67 tokens to every session and 3,125 once invoked, about $0.0003 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 2026-08-30.
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