Conciseness

The skill is quite long (~400+ lines) with many effect examples that follow a repetitive pattern (import, create pass, add to composer). While each individual snippet is lean, the sheer volume of effects listed (bloom, FXAA, SMAA, SSAO, DOF, film grain, vignette, color correction, gamma, pixelation, glitch, halftone, outline, plus custom shaders) makes this more of a reference catalog than a focused skill. Some effects like the invert colors shader are trivial enough that Claude could derive them. However, there's minimal prose padding—most content is code.

Actionability

Every effect includes complete, copy-paste ready code with proper imports, constructor arguments with inline comments explaining parameters, and runtime adjustment examples. The custom ShaderPass section provides full vertex and fragment shaders. The selective bloom example shows a complete working pattern including the darken/restore material technique.

Workflow Clarity

The Quick Start establishes the correct sequence (create composer → add render pass → add effect passes → use composer.render() in loop). The 'Combining Multiple Effects' section shows proper ordering with a comment noting AA should be last. The resize handling section covers an important operational concern. However, there's no explicit validation/debugging guidance (e.g., what to check if effects aren't visible, common pitfalls beyond the NOT renderer.render() comment). Since this isn't a destructive operation, the missing validation doesn't cap the score.

Progressive Disclosure

The content is entirely self-contained in one large file with no bundle files. The 'See Also' section references related skills, which is good. However, the extensive catalog of effects (selective bloom, custom shaders, chromatic aberration, etc.) could benefit from being split into a separate reference file, keeping SKILL.md as a concise overview with the most common effects and linking to detailed examples.

Specificity

Lists several specific actions/concepts: EffectComposer, bloom, DOF, screen effects, color grading, blur, glow, custom screen-space shaders. Good coverage but could mention a few more concrete operations like render pass chaining or specific pass types.

Completeness

Clearly answers both 'what' (Three.js post-processing with EffectComposer, bloom, DOF, screen effects) and 'when' (explicit 'Use when' clause covering adding visual effects, color grading, blur, glow, or creating custom screen-space shaders).

Trigger Term Quality

Excellent coverage of natural terms users would say: 'bloom', 'DOF', 'blur', 'glow', 'color grading', 'visual effects', 'post-processing', 'screen-space shaders', 'EffectComposer'. These are the exact terms Three.js developers use when seeking help with post-processing.

Distinctiveness Conflict Risk

Highly distinct niche: Three.js post-processing is a very specific domain. The combination of 'Three.js', 'EffectComposer', 'bloom', 'DOF', and 'screen-space shaders' creates a clear, unique identity that would not overlap with general rendering, animation, or other Three.js skills.