Validate test effectiveness with mutation testing using Stryker (TypeScript/JavaScript with Vitest or bun test via @hughescr/stryker-bun-runner) and mutmut (Python). Find weak tests that pass despite code mutations. Use to improve test quality.

Cloudflare Workers security with authentication, CORS, rate limiting, input validation. Use for securing APIs, JWT/API keys, or encountering auth failures, CORS errors, XSS/injection vulnerabilities.

Migrate to Cloudflare Workers from AWS Lambda, Vercel, Express, and Node.js. Use when porting existing applications to the edge, adapting serverless functions, or resolving Node.js API compatibility issues.

Cloudflare Workers observability with logging, Analytics Engine, Tail Workers, metrics, and alerting. Use for monitoring, debugging, tracing, or encountering log parsing, metric aggregation, alert configuration errors.

Configures HTTP security headers to protect against XSS, clickjacking, and MIME sniffing attacks. Use when hardening web applications, passing security audits, or implementing Content Security Policy.

This skill should be used when the user asks about "Cloudflare Workers with Bun", "deploying Bun to Workers", "wrangler with Bun", "edge deployment", "Bun to Cloudflare", or building and deploying applications to Cloudflare Workers using Bun.

Use for Docker with Bun, Dockerfiles, oven/bun image, containerization, and deployments.

Use when integrating Drizzle ORM with Bun's SQLite driver for type-safe schema definitions and migrations.

Use for Bun runtime, bunfig.toml, watch/hot modes, env vars, CLI flags, and module resolution.

Systematically trace bugs backward through call stack to find original trigger. Use when errors occur deep in execution and you need to trace back to find the original trigger.

Implements multi-language support using i18next, gettext, or Intl API with translation workflows and RTL support. Use when building multilingual applications, handling date/currency formatting, or supporting right-to-left languages.

Build MCP (Model Context Protocol) servers on Cloudflare Workers with tools, resources, and prompts.

Bun package manager commands (install, add, remove, update), workspaces, lockfiles, npm/yarn/pnpm migration. Use for dependency management with Bun.

Configures API gateways for routing, authentication, rate limiting, and request transformation in microservice architectures. Use when setting up Kong, Nginx, AWS API Gateway, or Traefik for centralized API management.

Designs RESTful APIs with proper resource naming, HTTP methods, status codes, and response formats. Use when building new APIs, establishing API conventions, or designing developer-friendly interfaces.

Review WooCommerce code changes for coding standards compliance. Use when reviewing code locally, performing automated PR reviews, or checking code quality in WooCommerce projects.

Database sharding for PostgreSQL/MySQL with hash/range/directory strategies. Use for horizontal scaling, multi-tenant isolation, billions of records, or encountering wrong shard keys, hotspots, cross-shard transactions, rebalancing issues.

Implements real-time WebSocket communication with connection management, room-based messaging, and horizontal scaling. Use when building chat systems, live notifications, collaborative tools, or real-time dashboards.

Comprehensive Cloudflare account management for deploying Workers, KV Storage, R2, Pages, DNS, and Routes. Use when deploying cloudflare services, managing worker containers, configuring KV/R2 storage, or setting up DNS/routing. Requires CLOUDFLARE_API_KEY in .env and Bun runtime with dependencies installed.

Use when building or running SvelteKit apps on Bun, including SSR, adapters, and Bun-specific APIs