002-components

Coding rules for React Three Fiber, a React library for building 3D scenes with Three.js. They describe how visual components should work with an entity-component-system, a way to keep game data and logic separate from rendering.

In plain words
What is it for?
Use them when building or reviewing React Three Fiber game components. They cover component structure, reacting to entity data, loading assets, cleanup, and patterns to avoid.
Why use it?
They keep display code focused on drawing while systems handle game behavior. This reduces tangled state, unsafe data changes, and resource leaks when models or textures are loaded.

Cursor rule for Cursor

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/instructa/viber3d/002-components
Clone the repo
git clone --depth 1 https://github.com/instructa/viber3d

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 318 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 $0.00318
Opus 5 $0.00000 $0.00159
Sonnet 5 $0.00000 $0.00064
Haiku 4.5 $0.00000 $0.00032

Measured yesterday against content hash 1465559b1e82, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

002-components 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.

templates/starter-next/.cursor/rules/002-components.mdc · 49 lines

What it actually says

R3F Component Guidelines

Core Principles

  • Use functional components for R3F with ECS data read via hooks.
  • Keep components strictly presentational. All game logic should reside in systems.
  • Use useTraitEffect(entity, Trait, callback) to reflect ECS changes on mesh references.

Example Structure

function EnemyView({ entity }: { entity: Entity }) {
  const ref = useRef<THREE.Mesh | null>(null)

  // React to trait changes only for visual updates
  useTraitEffect(entity, Transform, (t) => {
    if (ref.current && t) {
      ref.current.position.copy(t.position)
      ref.current.rotation.copy(t.rotation)
    }
  })

  return (
    <mesh ref={ref}>
      <sphereGeometry args={[0.5, 16, 16]} />
      <meshStandardMaterial color="red" />
    </mesh>
  )
}

Asset Loading and Cleanup

  • Use React Three Fiber helpers like useGLTF or useTexture for loading models or textures.
  • Dispose geometry and materials in a cleanup function if creating many dynamic objects over time.

Anti-Patterns

  • Do not place ECS or game logic in React state.
  • Do not mutate ECS traits directly from a component. Use systems or actions.
  • Do not rely on useFrame for core game logic; reserve it for minor visual effects only.
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 · 49 lines · 0 tokens per session scan A 1465559b1e82

Subscribe to this mod's changes

002-components is a cursor rule published in the GitHub repository instructa/viber3d (623 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 318 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.