Build durable workflows with Cloudflare Workflows (GA April 2025). Features step.do, step.sleep, waitForEvent, Vitest testing, automatic retries, and state persistence for long-running tasks. Use when: creating workflows, implementing retries, or troubleshooting NonRetryableError, I/O context, serialization errors.
Store and transform images with Cloudflare Images API and transformations. Use when: uploading images, implementing direct creator uploads, creating variants, generating signed URLs, optimizing formats (WebP/AVIF), transforming via Workers, or debugging CORS, multipart, or error codes 9401-9413.
Build MCP servers on Cloudflare Workers - the only platform with official remote MCP support. TypeScript-based with OAuth, Durable Objects, and WebSocket hibernation. Prevents 22 documented errors. Use when: deploying remote MCP servers, implementing OAuth, or troubleshooting URL path mismatches, McpAgent exports, CORS issues.
Build MCP servers with TypeScript on Cloudflare Workers. Covers tools, resources, prompts, tasks, authentication (API keys, OAuth, Zero Trust), and Cloudflare service integrations. Use when exposing APIs to LLMs or troubleshooting export syntax errors, transport leaks, or CORS misconfigurations.
Set up serverless Postgres with Neon or Vercel Postgres for Cloudflare Workers/Edge. Includes connection pooling, git-like branching, and Drizzle ORM integration. Use when: setting up edge Postgres, troubleshooting "TCP not supported", connection pool exhausted, or SSL config errors.
Build ChatGPT apps with MCP servers on Cloudflare Workers. Extend ChatGPT with custom tools and interactive widgets (HTML/JS UI). Use when: developing ChatGPT extensions, implementing MCP servers, or troubleshooting CORS, widget 404s, MIME types, or ASSETS binding errors.
Store objects with R2's S3-compatible storage on Cloudflare's edge. Use when: uploading/downloading files, configuring CORS, generating presigned URLs, multipart uploads, managing metadata, or troubleshooting R2_ERROR, CORS failures, presigned URL issues, or quota errors.
Build type-safe APIs with Hono for Cloudflare Workers, Deno, Bun, Node.js. Routing, middleware, validation (Zod/Valibot), RPC, streaming (SSE), WebSocket, security (CSRF, secureHeaders). Use when: building Hono APIs, streaming SSE, WebSocket, validation, RPC. Troubleshoot: validation hooks, RPC types, middleware chains.
Audit claude-skills with systematic 9-phase review: standards compliance, official docs verification, code accuracy, cross-file consistency, and version drift detection. Use when investigating skill issues, major updates detected, skill not verified >90 days, or before marketplace submission.
Build document Q&A with Gemini File Search - fully managed RAG with automatic chunking, embeddings, and citations. Upload 100+ file formats, query with natural language. Use when: document Q&A, searchable knowledge bases, semantic search. Troubleshoot: document immutability, storage quota (3x), chunking config, metadata limits (20 max), polling timeouts.
Add headless Chrome automation with Puppeteer/Playwright on Cloudflare Workers. Use when: taking screenshots, generating PDFs, web scraping, crawling sites, browser automation, or troubleshooting XPath errors, browser timeouts, binding not passed errors, or session limits.
Build async message queues with Cloudflare Queues for background processing. Use when: handling async tasks, batch processing, implementing retries, configuring dead letter queues, managing consumer concurrency, or troubleshooting queue timeout, batch retry, message loss, or throughput exceeded.
Run LLMs and AI models on Cloudflare's GPU network with Workers AI. Includes Llama 4, Gemma 3, Mistral 3.1, Flux images, BGE embeddings, streaming, and AI Gateway. Handles 2025 breaking changes. Use when: implementing LLM inference, images, RAG, or troubleshooting AI_ERROR, rate limits, max_tokens, BGE pooling.
Build React chat interfaces with Vercel AI SDK v6. Covers useChat/useCompletion/useObject hooks, message parts structure, tool approval workflows, and 12 UI error solutions. Use when: implementing AI chat UIs, migrating v5→v6, troubleshooting "useChat failed to parse stream", "stale body values", or React update depth errors.
Discover patterns, rules, and interfaces through iterative analysis cycles. Use when analyzing business rules, technical patterns, security, performance, integration points, or domain-specific areas. Includes cycle pattern for discovery to documentation to review workflow.
Domain-Driven Design tactical and strategic patterns including entities, value objects, aggregates, bounded contexts, and consistency strategies. Use when modeling business domains, designing aggregate boundaries, implementing business rules, or planning data consistency.
System architecture patterns including monolith, microservices, event-driven, and serverless, with C4 modeling, scalability strategies, and technology selection criteria. Use when designing system architectures, evaluating patterns, or planning scalability.
Consistent error patterns, validation approaches, and recovery strategies. Use when implementing input validation, designing error responses, handling failures gracefully, or establishing logging practices. Covers operational vs programmer errors, user-facing vs internal errors, and recovery mechanisms.
環境変数、アーキテクチャ設計、ビルド・テストコマンドを定義。環境設定、アーキテクチャ設計時に使用。
フロントエンドの環境変数、コンポーネント設計、データフローを定義。React環境設定時に使用。
Detects code smells, anti-patterns, and readability issues. Use when implementing features, reviewing code, or refactoring.
Core software engineering principles (SOLID, DRY, YAGNI, KISS) with detection patterns and refactoring guidance. Load when reviewing code quality, planning architecture, or identifying technical debt.
Systematic approach for creating minimal-change, reversible implementation plans. Claude invokes this skill when transforming requirements/research into executable blueprints. Emphasizes simplicity, safety, and clear verification steps.
Systematic methodology for identifying, capturing, and documenting reusable patterns from implementations. Enables automatic learning and knowledge-core.md updates. Claude invokes this after successful implementations to preserve institutional knowledge.
