Use when developing WordPress block themes: theme.json (global settings/styles), templates and template parts, patterns, style variations, and Site Editor troubleshooting (style hierarchy, overrides, caching).
Use when writing WordPress backend/server-side code - PHP development, database queries, REST API endpoints, admin interfaces, settings pages, custom post types, taxonomies, cron jobs, WP-CLI commands, plugin architecture, hooks system, OOP patterns, security (nonce, sanitization, SQL injection), performance optimization, and WordPress.org submission
Use when writing WordPress frontend/client-side code - CSS styling, JavaScript interactivity, HTML templates, theme development, Gutenberg blocks, responsive design, accessibility, browser compatibility, asset optimization, and modern frontend workflows (webpack, npm, build tools)