Optimize test suites using mutation testing to maximize mutation kill rate with minimal tests. Use when you need to reduce test suite size while maintaining quality, identify redundant tests, improve mutation coverage, or validate test effectiveness. The skill analyzes test coverage, execution intervals, and redundancy using mutation operators, selects or generates a minimal subset of tests that maximizes mutation kill rate, and outputs an optimized test suite with detailed reports showing killed and surviving mutants. Supports multiple programming languages and mutation testing frameworks.

Explain why counterexamples violate specifications by analyzing formal specifications (temporal logic, invariants, pre/postconditions, code contracts), informal requirements (user stories, acceptance criteria), test specifications (assertions, property-based tests), and providing step-by-step traces showing state changes, comparing expected vs actual behavior, identifying root causes, and assessing violation impact. Use when debugging test failures, understanding model checker output, explaining runtime assertion violations, analyzing static analysis warnings, or teaching specification concepts. Produces structured markdown explanations with traces, comparisons, state diagrams, and cause chains. Triggers when users ask why something failed, explain a violation, understand a counterexample, debug a specification, or analyze why a test fails.

Uses abstract interpretation to automatically infer loop invariants, function preconditions, and postconditions for formal verification. Generates invariants that capture program behavior and support correctness proofs in Dafny, Isabelle, Coq, and other verification systems. Use when adding formal specifications to code, generating verification conditions, inferring contracts for functions, or discovering loop invariants for proofs.

**WORKFLOW SKILL** — Migrate ASP.NET Web Forms Identity and Membership authentication to Blazor Server Identity. Covers OWIN→Core middleware, login/register/logout minimal API endpoints, BWFC login controls, cookie auth under Interactive Server, and role-based authorization. WHEN: "migrate identity", "login page migration", "OWIN to core", "cookie auth blazor", "LoginView migration". INVOKES: dotnet CLI for identity scaffolding. FOR SINGLE OPERATIONS: use bwfc-migration for markup, bwfc-data-migration for EF.

This skill provides comprehensive instructions for interacting with the Notion API via REST calls. This skill should be used whenever the user asks to interact with Notion, including reading, creating, updating, or deleting pages, databases, blocks, comments, or any other Notion content. The skill covers authentication, all available endpoints, pagination, error handling, and best practices.

Use when the user asks to run Codex CLI (codex exec, codex resume) or references OpenAI Codex for code analysis, refactoring, or automated editing. Uses GPT-5.2 by default for state-of-the-art software engineering.

Use when the user asks to run Codex CLI (codex exec, codex resume) or references OpenAI Codex for code analysis, refactoring, or automated editing. Uses GPT-5.2 by default for state-of-the-art software engineering.

Helps the user configure the Google SecOps Remote MCP Server for Gemini CLI. Use this when the user asks to "set up" or "configure" the security tools for Gemini CLI.

Use when processing incoming emails with Postmark inbound webhooks — building reply-by-email, email-to-ticket, document extraction, or any workflow that receives and parses email.

Summarize or extract text/transcripts from URLs, podcasts, and local files (great fallback for “transcribe this YouTube/video”).

Summarize or extract text/transcripts from URLs, podcasts, and local files (great fallback for “transcribe this YouTube/video”).

Summarize or extract text/transcripts from URLs, podcasts, and local files (great fallback for “transcribe this YouTube/video”).

iMessage/SMS CLI for listing chats, history, and sending messages via Messages.app.

Create distinctive, production-grade frontend interfaces with high design quality. Use this skill when the user asks to build web components, pages, artifacts, posters, or applications (examples include websites, landing pages, dashboards, React components, HTML/CSS layouts, or when styling/beautifying any web UI). Generates creative, polished code and UI design that avoids generic AI aesthetics.

Align spec files with implementation. Detects drift between spec and code, surfaces discrepancies, user decides whether to update spec or code. Use when both a spec file and its implementation are in context.

Create distinctive, production-grade frontend interfaces with high design quality. Use this skill when the user asks to build web components, pages, artifacts, posters, or applications (examples include websites, landing pages, dashboards, React components, HTML/CSS layouts, or when styling/beautifying any web UI). Generates creative, polished code and UI design that avoids generic AI aesthetics.

Refactor Kotlin code toward clearer, more idiomatic design without breaking Spring behavior, serialization, persistence, or public contracts. Use when Java-flavored Kotlin needs cleanup, domain modeling should become more expressive, or boilerplate should be reduced, but the refactoring must remain safe for proxies, Jackson, JPA, configuration binding, and existing tests.

Develop AI-powered applications using Genkit in Node.js/TypeScript. Use when the user asks about Genkit, AI agents, flows, or tools in JavaScript/TypeScript, or when encountering Genkit errors, validation issues, type errors, or API problems.