starmapper: Skill for Claude Code

.agents/skills/core-web-vitals/SKILL.md

core-web-vitals is a skill for Claude Code, Codex from FlorianBruniaux/starmapper. It costs 65 tokens per session (2,965 once invoked), scanned A, original, no licence file.

A guide to improving Core Web Vitals, Google's measures of loading speed, responsiveness, and visual stability. It focuses on LCP, INP, and CLS.

In plain words
What is it for?
Use it to improve LCP, INP, or CLS, fix layout shifts, and address page-experience issues that affect search ranking.
Why use it?
It helps diagnose pages that load slowly, respond late to input, or shift while being viewed. These problems can hurt user experience and search visibility.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

This is FlorianBruniaux/starmapper's own configuration. It tells Claude Code and Codex how to work on starmapper 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 starmapper configures →

Reuse

Borrowing it

Nothing to install: this file belongs to FlorianBruniaux/starmapper. 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/FlorianBruniaux/starmapper/main/.agents/skills/core-web-vitals/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/FlorianBruniaux/starmapper

Made for: Claude Code, Codex.

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 core-web-vitals

README.md
[![agentmods](https://agentmods.dev/badge/skills/florianbruniaux/starmapper/core-web-vitals/github.svg)](https://agentmods.dev/skills/florianbruniaux/starmapper/core-web-vitals)
Your own site
<a href="https://agentmods.dev/skills/florianbruniaux/starmapper/core-web-vitals"><img src="https://agentmods.dev/badge/skills/florianbruniaux/starmapper/core-web-vitals/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 core-web-vitals

Your own site · 80×15
<a href="https://agentmods.dev/skills/florianbruniaux/starmapper/core-web-vitals"><img src="https://agentmods.dev/badge/skills/florianbruniaux/starmapper/core-web-vitals.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,965 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00065 $0.02965
Opus 5 $0.00032 $0.01483
Sonnet 5 $0.00013 $0.00593
Haiku 4.5 $0.00006 $0.00297

Measured 9d ago against content hash d670ca158503, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

core-web-vitals 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 9d 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.

.agents/skills/core-web-vitals/SKILL.md · 438 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 9d ago First seen · 438 lines · 65 tokens per session scan A d670ca158503

Subscribe to this mod's changes

core-web-vitals is a skill published in the GitHub repository FlorianBruniaux/starmapper (84 stars, last pushed 7d ago), with no licence file. It adds 65 tokens to every session and 2,965 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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