Python
Python 3.11+ performance optimization guidelines (formerly python-311). This skill should be used when writing, reviewing, or refactoring Python code to ensure optimal performance patterns. Triggers on tasks involving asyncio, data structures, memory management, concurrency, loops, strings, or Python idioms.
Deterministic Metric Design
Inventing deterministic metrics — turning a fuzzy property like 'maintainability', 'risk', or 'how reducible this code is' into a deterministic, computable number an agent can trust and optimize. Covers the path from construct to adoption — operationalizing the construct, confronting computability limits (Kolmogorov, Rice) with sound proxies, picking the right measurement scale, proving propertie…
Ui Design
UI/UX and frontend design best practices guidelines (formerly frontend-design). This skill should be used when writing, reviewing, or designing frontend code to ensure accessibility, performance, and usability. Triggers on tasks involving HTML structure, CSS styling, responsive layouts, form design, animations, or accessibility improvements.
Implementation Design Patterns
Implementation guide for the 22 Gang of Four design patterns in TypeScript, distilled from refactoring.guru. Use this skill when writing, refactoring, or reviewing TypeScript that exhibits a pattern-shaped problem — class-explosion from inheritance, conditionals switching on type, tight coupling to concrete classes, tree-shaped models, runtime algorithm selection, undo/redo, snapshot-and-restore,…
Web Taste
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Think
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Code Simplifier
Code simplification skill for improving clarity, consistency, and maintainability while preserving exact behavior. Use when simplifying code, reducing complexity, cleaning up recent changes, applying refactoring patterns, or improving readability. Triggers on tasks involving code cleanup, simplification, refactoring, or readability improvements.
Implementation Functional Patterns
TypeScript's functional answers to the 22 Gang of Four classes — factory functions (Factory Method, Abstract Factory, Prototype, Memento), module-scope singletons, fluent immutable builders, wrapper functions (Adapter, Facade), native Proxy, WeakMap caches (Flyweight), discriminated unions with exhaustive match (State, Visitor, Composite), event emitters and signals (Mediator, Observer), pipeline…
Nuqs Codemod Runner
Migrates a nuqs codebase off pre-v2.5 patterns — deprecated `throttleMs`, hand-rolled setTimeout/useState debounce around `useQueryState`, unchecked `parseAsJson` casts, unversioned `nuqs/adapters/react-router` imports, or `ParserBuilder<T>` type references. Scans the repo, produces a dry-run report, asks for confirmation, applies AST codemods, then runs `tsc --noEmit` + the user's lint as a gate…
Acceptance Pipeline Catalog
Use when implementing, reviewing, or debugging a Gherkin acceptance-test pipeline with mutation testing. Covers parser, JSON IR, generator, runtime, step handlers, test runner, mutator, value mutation rules, execution, result classification, reporting, project layout, conformance, and agent setup. Based on Uncle Bob's Acceptance Pipeline Specification. Trigger even when the user mentions Gherkin…
Msw
MSW (Mock Service Worker) best practices for API mocking in tests (formerly test-msw). This skill should be used when setting up MSW, writing request handlers, or mocking HTTP APIs. This skill does NOT cover general testing patterns (use test-vitest or test-tdd skills) or test methodology.
Ruby Optimise
Ruby performance optimization guidelines. This skill should be used when writing, reviewing, or refactoring Ruby code to ensure optimal performance patterns. Triggers on tasks involving object allocation, collection processing, ActiveRecord queries, string handling, concurrency, or Ruby runtime configuration.
React Hook Form Audit
Audits a Next.js (App Router, 14/15+) codebase for React Hook Form anti-patterns — watch() at form root, Controller inlined in parent, async submit without try/catch, missing setError on server failures, RHF in non-"use client" files, RHF mixed with useActionState, schemas defined inside components, useFieldArray without field.id keys, register({ disabled }) for visual disabling. Read-only; emits…
Zod
Zod schema validation best practices for type safety, parsing, and error handling. This skill should be used when defining z.object schemas, using z.string validations, safeParse, or z.infer. This skill does NOT cover React Hook Form integration patterns (use react-hook-form skill) or OpenAPI client generation (use orval skill).
Playwright
Playwright testing best practices for Next.js applications (formerly test-playwright). This skill should be used when writing, reviewing, or debugging E2E tests with Playwright. Triggers on tasks involving test selectors, flaky tests, authentication state, API mocking, hydration testing, parallel execution, CI configuration, or debugging test failures.
Acceptance Pipeline Feature Design
Designs new features, extensions, or modifications to Uncle Bob's Acceptance Pipeline Specification — new mutation strategies, Gherkin syntax support, report formats, pipeline stages, IR fields, or handler patterns. Trigger when someone asks "how would I add X to the acceptance pipeline" or discusses spec-level changes to the parser, generator, runtime, mutator, or reporter components — even if t…
Expo Ui
Library reference for @expo/ui SwiftUI components on iOS — covers Host boundaries, modifier composition, iOS 26 Liquid Glass and Human Interface Guidelines composition rules, layout/input/navigation/display catalogues, and ObservableState patterns. Use this skill whenever writing or reviewing React Native code that imports from @expo/ui/swift-ui or @expo/ui/swift-ui/modifiers — including new Expo…
Tdd
Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd). This skill should be used when practicing TDD, writing tests first, designing tests before implementation, or reviewing test-first approaches. Triggers on "write tests first", "test before code", "red green refactor", "test driven development". This skill does NOT cover Vitest framework specifics (use vitest…
Bug Review
Use this skill when a user asks to review a pull request for bugs, wants AI code review focused on correctness issues, or runs /bug-review. Trigger on PR review, bug finding, code review, "review this PR", "check for bugs", "find issues in this PR". This is a multi-pass review workflow with 5 parallel passes, majority voting, independent Opus validation, and resolution rate tracking. Also trigger…
Nuqs
nuqs (type-safe URL query state) best practices for Next.js and other React frameworks. This skill should be used when writing, reviewing, or refactoring code that uses nuqs for URL state management. Triggers on tasks involving useQueryState, useQueryStates, search params, URL state, query parameters, nuqs parsers, limitUrlUpdates, Standard Schema, NuqsAdapter, or Next.js routing with state.
Nextjs
Next.js 16 App Router performance, caching, server components, server actions, routing, and codebase-hygiene best practices — plus a category-major review/refactor algorithm with codebase-level (remove/dedup/reuse) findings. This skill should be used when writing Next.js 16 App Router code, configuring caching with 'use cache', building Server Components, setting up parallel/intercepting routes,…
React Hook Form
React Hook Form performance optimization for client-side form validation using useForm, useWatch, useController, useFieldArray, and the v7.55+ subscribe() API. This skill should be used when building client-side controlled forms with React Hook Form library. This skill does NOT cover React 19 Server Actions, useActionState, or server-side form handling (use react-19 skill for those).
Vitest
Vitest testing framework patterns for test setup, async testing, mocking with vi.*, snapshots, and test performance (formerly test-vitest). This skill should be used when writing or debugging Vitest tests. This skill does NOT cover TDD methodology (use test-tdd skill), API mocking with MSW (use test-msw skill), or Jest-specific APIs.
Debug
Comprehensive debugging methodology for finding and fixing bugs (formerly debugging). This skill should be used when debugging code, investigating errors, troubleshooting issues, performing root cause analysis, or responding to incidents. Covers systematic reproduction, hypothesis-driven investigation, and root cause analysis techniques. Use when encountering exceptions, stack traces, crashes, se…
Radical Simplification
Cognitive moves for collapsing complexity — reframe, clarify, reduce, decompose, invert, constrain, transfer, generalize, audit — distilled from the working method of mathematicians, physicists, and software engineers known for turning hard problems into simple solutions (Pólya, Feynman, Hamming, Brooks, Knuth, Dijkstra, Lamport, Tao, Grothendieck, Munger, Hofstadter). Use when stuck on a complex…
Skill Authoring
Design and development best practices for Claude Code skills, MCP tools, and AI agent capabilities. Use when creating skills, writing SKILL.md files, designing tool descriptions, or optimizing triggers. Triggers on "create a skill", "skill template", "write skill instructions", SKILL.md, metadata.json, progressive disclosure, trigger optimization, MCP tool design, or skill testing. Does NOT cover…
Rust Refactor
Decision frameworks for Rust refactoring, simplification, module decomposition, and incremental migration. Use this skill when simplifying Rust code, splitting large files, removing dead abstractions, migrating types incrementally, or cleaning up feature flags. Triggers on Rust refactoring, simplification, module splitting, parameter cleanup, or incremental type migration.
12 Factor App
The Twelve-Factor App methodology for building scalable, maintainable cloud-native applications. Use when designing backend services, APIs, microservices, or any software-as-a-service application. Triggers on deployment patterns, configuration management, process architecture, logging, and infrastructure decisions.
React
React 19/19.2 modern patterns for concurrent rendering, Server Components, actions, ref-as-prop, document metadata, resource hints, hooks, and memoization — plus a category-major review/refactor algorithm with codebase-level (remove/dedup/reuse) findings. This skill should be used when writing React 19 components, using concurrent features, migrating from React 18, optimizing re-renders, OR audit…
Rust Write Tests
Expert-level Rust testing — the "What Could Break?" framework, five transformations from superficial to expert tests, flake hunting protocol, intent-based assertions, naming conventions, and a mandatory self-review checklist. Triggers on writing Rust tests, designing test cases, improving test quality, or reviewing test coverage.
Restful Hateoas
RESTful API design guidelines following the Richardson Maturity Model through to Level 3 (HATEOAS) for Ruby on Rails. This skill should be used when designing, building, reviewing, or refactoring REST APIs to ensure proper resource modeling, HTTP method semantics, hypermedia controls, content negotiation, and API evolvability. Triggers on tasks involving API controllers, serializers, routing, lin…
37signals Rails
37signals Rails coding principles and conventions from DHH, Jorge Manrubia, and the Fizzy/Basecamp/HEY codebase. This skill should be used when writing, reviewing, or refactoring Ruby on Rails code following the 37signals philosophy — vanilla Rails, CRUD controllers, rich domain models, concerns, no service objects, Hotwire, Turbo, Stimulus, Solid Queue, Solid Cache, Solid Cable, multi-tenancy, M…
Design Review
Structured UI design review — existing code (React/JSX, CSS, Tailwind) and, when behaviour matters, the running app in a real browser — reported as a prioritised Before / After / Why table. Covers visual hierarchy, spacing, typography, colour & contrast, component states, motion, responsiveness, accessibility, multi-page flow & navigation, and interaction continuity — grounded in Refactoring UI a…
Typescript
TypeScript performance, tsconfig, type errors, async patterns — triggered when the user asks to "optimize TypeScript performance", "speed up tsc compilation", "configure tsconfig.json", "fix type errors", "improve async patterns", or encounters TS errors (TS2322, TS2339, "is not assignable to"). Also triggers on .ts, .tsx, .d.ts file work involving type definitions, module organization, or memory…
Nuqs Scaffolder
Scaffolds URL-state filters for a Next.js page — typed `searchParams.ts` parser map and a `<Filters />` client component backed by `useQueryStates`. From a single JSON spec, generates four files in lockstep — client parser map, server loader/cache/serializer, client component, and Vitest test — all sharing the same parser definitions per the nuqs Standard Schema pattern. Trigger even when the use…
Expo
Expo React Native performance optimization guidelines. This skill should be used when writing, reviewing, or refactoring Expo React Native code to ensure optimal performance patterns. Triggers on tasks involving React Native components, navigation, lists, images, animations, bundle optimization, or mobile performance improvements.
Refactor
Code refactoring best practices based on Martin Fowler's catalog and Clean Code principles (formerly refactoring). This skill should be used when refactoring existing code, improving code structure, reducing complexity, eliminating code smells, or reviewing code for maintainability. Triggers on tasks involving extract method, rename, decompose conditional, reduce coupling, or improve readability.
Unifi Mcp
Local MCP server for the UniFi Network API
Rails Testing
Ruby on Rails testing best practices for writing effective, maintainable test suites with RSpec. This skill should be used when writing, reviewing, or refactoring Rails tests to ensure proper test design, data management, and coverage patterns. Triggers on tasks involving RSpec specs, model tests, request specs, system tests, factory definitions, Capybara interactions, Sidekiq job tests, or test…
Feature Arch
React feature-based architecture guidelines for scalable applications. This skill should be used when writing, reviewing, or refactoring React code to ensure proper feature organization. When invoked on a project, the agent produces a concrete target-architecture blueprint at docs/architecture/FEATURE-ARCH-TARGET.md showing the desired directory tree, per-feature public APIs, import-boundary matr…
Shadcn
shadcn/ui component library best practices and patterns (formerly shadcn-ui). This skill should be used when writing, reviewing, or refactoring shadcn/ui components to ensure proper architecture, accessibility, and performance. Triggers on tasks involving Radix primitives, Tailwind styling, form validation with React Hook Form, data tables, theming, or component composition patterns.
Ruby Refactor
Ruby refactoring guidelines from community best practices. This skill should be used when refactoring, reviewing, or restructuring Ruby code to improve design, readability, and maintainability. Triggers on tasks involving code smells, method extraction, conditional simplification, coupling reduction, design patterns, or Ruby idiom adoption.
Mui Base
MUI Base UI style guidelines for building headless React component libraries (formerly headless-ui-style). This skill should be used when creating unstyled UI components, compound components with render props, accessibility-first patterns, or component libraries that separate logic from styling. Extracted from the MUI Base UI codebase (github.com/mui/base-ui).
Terminal Ui
Terminal User Interface (TUI) performance and UX guidelines for TypeScript applications using Ink and Clack. This skill should be used when building CLI tools, interactive terminal prompts, or developer tooling with TUI components. Triggers on tasks involving TUI components, CLI prompts, terminal rendering, keyboard input handling, or developer tooling.
Rust Implement
Write production-grade Rust code using a multi-pass approach. Design types first, then implement, then simplify, then verify with automated lint. Use this skill whenever writing new Rust functions, structs, modules, or features. Triggers on Rust implementation, new Rust code, Rust functions, Rust modules, error handling in Rust, async Rust, or type design in Rust.
Ios Taste
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Tanstack Query
TanStack Query v5 performance optimization for data fetching, caching, mutations, and query patterns. This skill should be used when using useQuery, useMutation, queryClient, prefetch patterns, or TanStack Query caching. This skill does NOT cover generating query hooks from OpenAPI (use orval skill) or mocking API responses in tests (use test-msw skill).
React 19 Component Scaffolder
Scaffolds React 19 / React 19.2 code in TypeScript — components, Server Component pages, client islands, form actions with useActionState, context providers, custom hooks, reducers, or document metadata + resource hints. Generates production-grade code that follows React 19 idioms (ref-as-prop, <Context value={...}>, useActionState, inline metadata, useSyncExternalStore) and refuses deprecated Re…
Rails Dev
Ruby on Rails performance and maintainability optimization guidelines for building backend APIs and frontend web applications. This skill should be used when writing, reviewing, or refactoring Ruby on Rails code to ensure optimal patterns for controllers, models, ActiveRecord queries, caching, views, API design, security, and background jobs. Triggers on tasks involving Rails controllers, ActiveR…
Tailwind
Tailwind CSS v4 performance optimization and best practices guidelines (formerly tailwindcss-v4-style). This skill should be used when writing, reviewing, or refactoring Tailwind CSS v4 code to ensure optimal build performance, minimal CSS output, and correct usage of v4 features. Triggers on tasks involving Tailwind configuration, @theme directive, utility classes, responsive design, dark mode,…