What problem does it solve? Developing the MediaPlace REDAXO addon requires navigating a complex architecture: an esbuild-bundled overlay core, hand-edited widget assets, custom REST API endpoints, permission checks, and subtle pitfalls like opcache staleness, unpublished API functions, and lazy-loaded Metainfo extension points. This Skill encodes all of that institutional knowledge so changes are made correctly the first time. ## Core Features & Use Cases - Architecture guidance: Documents the five independently toggleable parts (Overlay, Input-Widget, classic integration, Metainfo canvas, YForm value type) and where each piece of code lives. - Critical-area checklists: Thirteen documented pitfalls covering API-addon version checks, permission enforcement, CSS dark-mode variable blocks, chunked bulk-action contracts, language file parity, and CLI boot limitations. - Verification discipline: Prescribed workflows for JS syntax checks, CSS variable audits, PHP linting, esbuild rebuilds, asset syncing, and live verification via curl and system logs. - Use Case: When adding a new REST endpoint to the addon, the Skill reminds you to register it in boot.php, set $published = true, add MediaPermission checks, and verify via curl rather than trusting a generic JS fetch error. ## Quick Start Use the mediaplace-dev skill to add a new filter option to the MediaPlace overlay grid and rebuild the bundle correctly.