Backend

Write efficient and secure database queries using parameterized statements, preventing SQL injection, and optimizing performance through proper indexing and eager loading. Use this skill when writing database queries, ORM query methods, SQL statements, or repository pattern implementations. Use this skill when optimizing query performance, preventing N+1 query problems, implementing transactions for data consistency, or adding query timeouts and caching strategies. Use this skill when working with SELECT statements, JOIN operations, WHERE clauses, or any code that interacts with the database to fetch or manipulate data. Use this skill when working with files in repositories/, queries/, services/, or data access layers that contain database query logic.

NetGraph scenario DSL for defining network topologies, traffic demands, failure policies, and analysis workflows in YAML. Use when: creating or editing .yaml/.yml network scenarios, defining nodes/links/groups, writing adjacency rules, configuring selectors or blueprints, setting up traffic matrices or failure policies, debugging DSL syntax or validation errors, or asking about NetGraph scenario structure.

Intelligent web browsing API that learns from patterns, discovers APIs automatically, and progressively eliminates browser rendering for 10x faster data extraction. Use when you need to extract content from websites, discover APIs, handle authenticated sessions, or automate multi-step browsing workflows.

Use this skill when adding new backend functionality (API endpoints + business logic).

Analyzes git history to identify commit patterns, branching habits, workflow inefficiencies, and collaboration opportunities. Use when users mention git workflows, commits, branches, rebasing, merge conflicts, PR strategy, force push, git aliases, or express frustration with git operations.

Follow project-wide development conventions for project structure, documentation, version control, code review, environment configuration, dependency management, and security practices. Use this skill when setting up new projects, organizing file structures, writing project documentation, creating Git branches and commits, configuring environment variables, managing dependencies, setting up CI/CD pipelines, or implementing security practices. Apply when working on project setup tasks, creating documentation files (README.md, ARCHITECTURE.md, DATABASE_SCHEMA.md, API_REFERENCE.md, SETUP.md), Git workflow operations, .env files, package.json/bun.lockb, Docker configurations, or any cross-cutting project concerns. This skill ensures hybrid code organization (global shared code by type + feature-specific code with nested subdirectories), required documentation (README, ARCHITECTURE, DATABASE_SCHEMA, API_REFERENCE, SETUP - written before coding then updated), GitHub Flow workflow (main branch production-ready, feat

FastAPI patterns for building high-performance Python APIs. Covers routing, dependency injection, Pydantic models, background tasks, WebSockets, testing, and production deployment.

백엔드 개발자 온보딩 실습 (SAX-Backend 패키지 전용). Use when (1) sax-core/skill:onboarding에서 호출,(2) 백엔드 개발자 온보딩 실습 필요 시. API 설계 및 백엔드 워크플로우 체험.

Comprehensive guide to Python async/await patterns, best practices, and anti-patterns. Covers asyncio fundamentals, coroutines, async context managers, task management, common libraries (aiohttp, aiofiles, asyncpg), framework integration (FastAPI, Django), performance considerations, and proper exception handling. Use when reviewing or writing asynchronous Python code.

Define and structure database models with proper data integrity, relationships, and validation. When creating or modifying database model files (models/*, *.model.ts, schema.ts, schema.prisma, drizzle.config.ts). When working on ORM schemas, database table definitions, or data structure specifications. When defining model relationships, constraints, foreign keys, indexes, or validation rules. When implementing timestamps, data types, or cascade behaviors for database entities.

Use when need to bypass Cloudflare protection, scrape websites with anti-bot measures, render JavaScript pages, or simulate real browser behavior for web scraping

This skill should be used when generating and editing images using the Gemini API (Nano Banana Pro). It applies when creating images from text prompts, editing existing images, applying style transfers, generating logos with text, creating stickers, product mockups, or any image generation/manipulation task. Supports text-to-image, image editing, multi-turn refinement, and composition from multiple reference images.

Use when creating new repositories or initializing existing directories with KellerAI standards. Provides step-by-step workflow for TaskMaster setup, Claude Code configuration, MCP server integration, and standard directory structure.

Generate production-ready Express + TypeScript + PostgreSQL + Redis projects. Use when the user wants to create a new backend service, API, or microservice from scratch. Automatically invoked when discussing project scaffolding or generation.

Expert assistant for Juju charm development using jhack utilities. Use when debugging charms, inspecting relations, syncing code, replaying events, testing scenarios, or performing rapid development iterations. Keywords include jhack, Juju debugging, charm testing, relation inspection, event replay, sync, tail, fire, show-relation, show-stored.

Comprehensive Shopify development expert with access to 24 official documentation files covering APIs (GraphQL Admin, Storefront, REST), app development, themes, Liquid, Hydrogen, checkout, extensions, webhooks, Functions, CLI, subscriptions, payments, and all platform features. Invoke when user mentions Shopify, e-commerce, online store, product management, orders, checkout, themes, or headless commerce.

Interactive Archon integration for knowledge base and project management via REST API. On first use, asks for Archon host URL. Use when searching documentation, managing projects/tasks, or querying indexed knowledge. Provides RAG-powered semantic search, website crawling, document upload, hierarchical project/task management, and document versioning. Always try Archon first for external documentation and knowledge retrieval before using other sources.

Search and download torrents using ArcTorrent API and WebTorrent. Use when users request to: (1) Search for torrents across multiple sources, (2) Download content via magnet links, (3) Find torrents filtered by seeder counts, or any torrent-related tasks

Master advanced ASP.NET Core development including Entity Framework Core, authentication, testing, and enterprise patterns for production applications.

Build async APIs with FastAPI, including endpoints, dependency injection, validation, and testing. Use when creating REST APIs, web backends, or microservices.