Use the Open Design skill od:prototype:social-youtube-thumbnail (YouTube Thumbnail).

Treat the rest of the user's message as the brief. If nothing more specific was given, use: "Use the YouTube Thumbnail template to design a thumbnail for my video. Make the promise of the video readable in under a second: one short hook line, one strong focal subject, high contrast. Use real content from my brief and avoid lorem ipsum or placeholder images."

Call prepare_open_design_brief (the open-design MCP server's tool) with skillId "od:prototype:social-youtube-thumbnail" and this brief — call list_open_design_design_systems first if the user names a brand or visual direction, or recommend_open_design_design_systems if they name none and no design system is active. Author the files yourself with your own file-editing tools per the returned instructions, then call register_open_design_artifact.