Three.js asset loading - GLTF, textures, images, models, async patterns. Use when loading 3D models, textures, HDR environments, or managing loading progress.

Guides Test-Driven Development workflow with Red-Green-Refactor cycle. Use when the user wants to implement a feature using TDD, write tests first, follow test-driven practices, or mentions red-green-refactor.

Creates form objects for complex form handling with TDD. Use when building multi-model forms, search forms, wizard forms, or when user mentions form objects, complex forms, virtual models, or non-persisted forms.

Implements transactional emails with Action Mailer and TDD. Use when creating email templates, notification emails, password resets, email previews, or when user mentions mailer, email, notifications, or transactional emails.

Implements real-time WebSocket communication with connection management, room-based messaging, and horizontal scaling. Use when building chat systems, live notifications, collaborative tools, or real-time dashboards.

Optimizes web application performance through code splitting, lazy loading, caching strategies, and Core Web Vitals monitoring. Use when improving page load times, implementing service workers, or reducing bundle sizes.

Four-phase debugging framework that ensures root cause investigation before attempting fixes. Never jump to solutions. Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

Critically review and refine tests generated during a coding session. Use this skill when the user asks to review tests, clean up tests, refine tests, prune tests, improve test quality, or remove useless/low-value tests. Also use when the user says 'review my tests', 'clean up tests', or mentions test quality after a coding session.

Extracts an SMV (NuSMV/nuXmv) finite-state model from code or state-machine descriptions, for CTL/LTL model checking of reactive systems. Use when verifying hardware-adjacent or embedded logic, when the state space is naturally finite and small, or when CTL branching-time properties are needed.

Scans source code for security vulnerabilities by applying Project CodeGuard rules — injection, unsafe deserialization, XSS, path traversal, broken access control. Use when performing a security audit, when reviewing a PR that touches request handlers or database queries, when the user asks for a vulnerability scan, or when wiring security checks into CI.

Matches code against Project CodeGuard's catalog of known-dangerous patterns — banned C functions, weak crypto primitives, hardcoded credentials, deprecated APIs. Use when grepping for low-hanging security fruit, when enforcing a ban-list in CI, or when the user asks to check for known-bad patterns.

Comprehensive PDF manipulation toolkit for extracting text and tables, creating new PDFs, merging/splitting documents, and handling forms. When Claude needs to fill in a PDF form or programmatically process, generate, or analyze PDF documents at scale.

Guides implementation of agent memory systems, compares production frameworks (Mem0, Zep/Graphiti, Letta, LangMem, Cognee), and designs persistence architectures for cross-session knowledge retention. Use when the user asks to "implement agent memory", "persist state across sessions", "build knowledge graph for agents", "track entities over time", "add long-term memory", "choose a memory framework", or mentions temporal knowledge graphs, vector stores, entity memory, adaptive memory, dynamic memory or memory benchmarks (LoCoMo, LongMemEval).

Bun package manager commands (install, add, remove, update), workspaces, lockfiles, npm/yarn/pnpm migration. Use for dependency management with Bun.

Structured approach to workplace conflicts, performance discussions, and challenging feedback using preparation-delivery-followup framework. Use when preparing for tough conversations, addressing conflicts, giving critical feedback, or navigating sensitive workplace discussions.

Generate complete SEO meta tags for every page. Covers title patterns, meta descriptions, Open Graph, Twitter Cards, and JSON-LD structured data (LocalBusiness, Service, FAQ, BreadcrumbList). Use when: building pages, adding social sharing, implementing structured data, optimizing for search engines.

Generate architecture documentation using C4 model Mermaid diagrams. Use when asked to create architecture diagrams, document system architecture, visualize software structure, create C4 diagrams, or generate context/container/component/deployment diagrams. Triggers include "architecture diagram", "C4 diagram", "system context", "container diagram", "component diagram", "deployment diagram", "document architecture", "visualize architecture".

Structured approach to workplace conflicts, performance discussions, and challenging feedback using preparation-delivery-followup framework. Use when preparing for tough conversations, addressing conflicts, giving critical feedback, or navigating sensitive workplace discussions.

Generate architecture documentation using C4 model Mermaid diagrams. Use when asked to create architecture diagrams, document system architecture, visualize software structure, create C4 diagrams, or generate context/container/component/deployment diagrams. Triggers include "architecture diagram", "C4 diagram", "system context", "container diagram", "component diagram", "deployment diagram", "document architecture", "visualize architecture".