Behavioral Product Design

Apply Swift API Design Guidelines to name, label, and document Swift APIs. Covers argument label rules (prepositional phrase rule, grammatical phrase rule, first-label omission), mutating/nonmutating pair naming (-ed/-ing participle pattern, form- prefix, sort/sorted, formUnion/union), side-effect naming (noun for pure, verb for mutating), documentation comment structure (summary by declaration kind, O(1) complexity rule), clarity at call site, role-based naming, protocol naming (-able/-ible/-ing), default arguments over method families, casing conventions, and terminology. Use when designing new Swift APIs, reviewing naming and argument labels, writing documentation comments, or refactoring for call site clarity.

Comprehensive game design theory covering MDA framework, player psychology, balance principles, and progression systems. Master why games are fun.

**MANDATORY prerequisite** — you MUST invoke this skill BEFORE every `use_figma` tool call. NEVER call `use_figma` directly without loading this skill first. Skipping it causes common, hard-to-debug failures. Trigger whenever the user wants to perform a write action or a unique read action that requires JavaScript execution in the Figma file context — e.g. create/edit/delete nodes, set up variables or tokens, build components and variants, modify auto-layout or fills, bind variables to properties, or inspect file structure programmatically.

Decide how to split skill content between SKILL.md and reference files for context efficiency and reliable triggering. Use this whenever creating a new Claude skill, refactoring an existing one, or when a SKILL.md is growing past 300-400 lines. Also trigger when the user mentions "progressive disclosure", "reference files", "splitting skills", "skill bundling", "context window for skills", "SKILL.md too long", "what goes in references/", "skill structure", or expresses any uncertainty about where to put content within a skill. Use this even if the user phrases the question as a triggering problem ("how do I make my skill trigger better"), because that question is often confused with the splitting question and needs to be disentangled first.

ui ux pro max skill

frontend design