Backend

This skill should be used when debugging full-stack issues that span UI, backend, and database layers. It provides a systematic workflow to detect errors, analyze root causes, apply fixes iteratively, and verify solutions through automated server restarts and browser-based testing. Ideal for scenarios like failing schedulers, import errors, database issues, or API payload problems where issues originate in backend code but manifest in the UI.

This skill should be used when the user asks to "add permissions to a policy", "create a policy with roles", "set up role permissions", "configure rolePermissions", "use BasePolicy", or when working with Laravel policies that need role-based permission management. Also activate when creating or modifying policies in a project using philsquare/permissions.

A workflow for capturing evidence and citations to create reproducible analyses and audit trails.

Validates LangGraph implementations for correctness, consistency, and integration readiness. Use this skill when implementing, reviewing, or debugging any LangGraph code - agents, nodes, subgraphs, state schemas, or graph compositions. Prevents common LangGraph failures including orphaned nodes, state key mismatches, broken conditional edges, and integration incompatibilities. Triggers on LangGraph development tasks, code reviews, or when debugging graph execution issues.

Use after brainstorming to apply vanilla-rails patterns to a feature, producing structured handoff for implementation planning. Invoke with /shape.

Analyze code complexity and maintainability including cyclomatic complexity, function length, nesting depth, and cognitive load. Use when reviewing code maintainability, refactoring candidates, or technical debt assessment.

Creates, analyzes, updates, and improves Claude Code agent skills including YAML frontmatter, allowed-tools field, progressive disclosure, and skill authoring workflows. Use when user asks how skills work, what agent skills are, explaining skill concepts, understanding SKILL.md structure, describing .md files organization, skill authoring process, asked to create a new skill, evaluate existing skills for improvements, optimize skills for AI/Claude effectiveness, suggest converting current logic into a skill, update outdated skill information, or when user mentions skill validation, best practices, supporting files, skill security, API integration, or technical architecture.

创建高质量 MCP（模型上下文协议）服务器的指南，使 LLM 能够通过精心设计的工具与外部服务交互。在构建 MCP 服务器以集成外部 API 或服务时使用，无论是使用 Python（FastMCP）还是 Node/TypeScript（MCP SDK）。

Backend-Frontend integration patterns expert. Type-safe API contracts with Pydantic-Zod validation sync (Python FastAPI) or Prisma-TypeScript native (Next.js). Shadcn forms connected to backend, error handling, loading states. Use when creating full-stack features.

Use when Codex must fetch web pages, scrape selectors, or crawl sitemaps through the remote Fetch/Web MCP server catalog entry.

Skill for creating and editing Spatie Laravel Data classes following Prowi conventions. Use when working with Data classes, DTOs, or data transfer objects. Enforces proper constructor-based properties, annotation-based validation, and Collection usage.

Proactively discover, install, and create Claude skills for specialized tasks. AUTOMATICALLY activates when encountering niche domains, unfamiliar APIs, specialized knowledge areas, or when user expresses wanting to learn/know something new. Searches the community registry at claude-plugins.dev and auto-installs matching skills. Creates new skills when no match exists. Use when user says "I want to know...", "help me with [specialized domain]", or when you recognize a task requires specialized expertise you don't have.

Web scraping, screenshots, form filling, file downloads/uploads, Google/DuckDuckGo image search, YouTube video downloading, and TikTok video downloading.

Write tests for backend services, APIs, and database access. Use when testing Express/Fastify handlers, services with database calls, or integration tests.

Create secure FastAPI routes for task CRUD with search/filter/sort query params and JWT auth when backend endpoints are needed

Discover Java API signatures from compiled JARs using javap instead of guessing or relying on incomplete documentation. Use when encountering unknown methods, pagination patterns, union types, or compilation errors from incorrect API assumptions.

Complex skill for testing directory support with nested dirs, binary files, and multiple file types

Guide for porting code from optaic-v0 to optaic-trading. Use when migrating DataAPI, pipelines, stores, accessors, operators, or expressions into the Resource/Activity architecture. Covers pattern mappings for permission checks, audit trails, and catalog lookups.

Better Auth JWT verification for Python/FastAPI backends. Use when integrating Python APIs with a Better Auth TypeScript server via JWT tokens. Covers JWKS verification, FastAPI dependencies, SQLModel/SQLAlchemy integration, and protected routes.

Advanced yargs patterns for Node.js CLI argument parsing with subcommands, options, middleware, and validation