procedural-starfield

procedural-starfield is a skill for Claude Code, Codex from CK42BB/procedural-stars-threejs. It costs 226 tokens per session (8,031 once invoked), scanned A, original, MIT.

A Three.js guide for creating computer-generated night skies and space scenes in web browsers. It covers stars, nebulae, the Milky Way, sky changes over time, and fallback rendering for browsers without WebGPU.

In plain words
What is it for?
Use it to create procedural starfields, nebulae, moon and sunset-to-dawn transitions, twinkling stars, spectral star colours, and other Three.js space effects.
Why use it?
It provides a defined approach for building detailed celestial visuals instead of designing each sky effect from scratch. It also accounts for different browser graphics capabilities.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create procedural starfields, nebulae, moon and sunset-to-dawn transitions, twinkling stars, spectral star colours, and other Three.js space effects.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs
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.

Any agent
npx skills add CK42BB/procedural-stars-threejs --skill procedural-stars-threejs
Clone the repo
git clone --depth 1 https://github.com/CK42BB/procedural-stars-threejs

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 procedural-starfield

README.md
[![agentmods](https://agentmods.dev/badge/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs/github.svg)](https://agentmods.dev/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs)
Your own site
<a href="https://agentmods.dev/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs"><img src="https://agentmods.dev/badge/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs/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 procedural-starfield

Your own site · 80×15
<a href="https://agentmods.dev/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs"><img src="https://agentmods.dev/badge/skills/ck42bb/procedural-stars-threejs/procedural-stars-threejs.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 226 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 8,031 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 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 5.1 $0.00226 $0.08031
Opus 5 $0.00113 $0.04015
Sonnet 5 $0.00045 $0.01606
Haiku 4.5 $0.00023 $0.00803

Measured 11d ago against content hash 34421bfa3075, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

procedural-starfield 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 11d 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.

SKILL.md · 798 lines

How it starts

The opening of the file, as written. The whole thing — 798 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Procedural Starfield & Celestial Phenomena

Generate breathtaking night skies in Three.js — from photorealistic starfields to dreamy nebulae to dramatic celestial events.

Architecture Overview

┌──────────────────────────────────────────────────────┐
│               Night Sky Pipeline                      │
│                                                      │
│  SkyController (master orchestrator)                 │
│    ├── time progression (sunset → night → dawn)      │
│    ├── moon phase + position                         │
│    └── drives all layers:                            │
│                                                      │
│  ┌─ Layer 1: Sky Dome ──────────────────────────┐    │
│  │  Gradient background, horizon glow, zodiacal │    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 2: Stars ─────────────────────────────┐    │
│  │  Points with spectral color + magnitude      │    │
│  │  Twinkle, proper motion (optional)           │    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 3: Milky Way ─────────────────────────┐    │
│  │  Textured band or procedural FBM glow        │    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 4: Nebulae ───────────────────────────┐    │
│  │  Volumetric raymarched or billboard sprites  │    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 5: Celestial Bodies ──────────────────┐    │
│  │  Moon (phase lit), planets, sun glow         │    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 6: Transients ────────────────────────┐    │
│  │  Shooting stars, comets, eclipses, satellites│    │
│  └──────────────────────────────────────────────┘    │
│  ┌─ Layer 7: Deep Space (optional) ─────────────┐    │
│  │  Distant galaxies, star clusters, dust lanes │    │
│  └──────────────────────────────────────────────┘    │
└──────────────────────────────────────────────────────┘

Renderer Setup

import * as THREE from 'three';

async function createRenderer(canvas) {
  let renderer, gpuAvailable = false;
  try {
    const WebGPU = (await import('three/addons/capabilities/WebGPU.js')).default;
    if (WebGPU.isAvailable()) {
      const { default: WebGPURenderer } = await import(
        'three/addons/renderers/webgpu/WebGPURenderer.js'
      );
      renderer = new WebGPURenderer({ canvas, antialias: true });
      await renderer.init();
      gpuAvailable = true;
    }
  } catch (e) {}
  if (!renderer) {
    renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
    renderer.toneMapping = THREE.ACESFilmicToneMapping;
    renderer.toneMappingExposure = 1.0;
  }
  renderer.setSize(innerWidth, innerHeight);
  renderer.setPixelRatio(Math.min(devicePixelRatio, 2));
  return { renderer, gpuAvailable };
}

Read the full file on GitHub · 798 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. 11d ago First seen · 798 lines · 226 tokens per session scan A 34421bfa3075

Subscribe to this mod's changes

procedural-starfield is a skill published in the GitHub repository CK42BB/procedural-stars-threejs (6 stars, last pushed 7mo ago), licensed MIT. It adds 226 tokens to every session and 8,031 once invoked, about $0.0011 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.

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