Dev builds remote MCP server with inline MCP Apps video player for 5,500 meme clips
Mediocre-Number-5498 · reddit · 2026-11-16
A developer shared engineering notes on building a remote MCP server for ClipKaboom (5,500 reaction/meme clips for video editors), now listed on the official MCP Registry.
- Transport: stateless Streamable HTTP (JSON-RPC over POST /mcp) on a Cloudflare Worker, with Bearer API key and per-request plan checks.
- Tools: 9 tools including semantic search, trending, similar clips, download URLs, and boards.
- Inline player via MCP Apps: search tools point to a ui:// HTML resource; the player communicates with the host over postMessage (initialize/size-changed/open-link/download-file), falling back to text + thumbnails for clients without MCP Apps support.
- Semantic search lesson: pure vector search returned nothing for oddly specific prompts, so a keyword fallback was added.
- Download caps: KV's eventual consistency let parallel requests slip past quotas, so caps are enforced with one atomic D1 statement (INSERT ON CONFLICT ... WHERE n < cap RETURNING; no row = over cap).
The author asks which clients besides Claude and VS Code currently render MCP Apps.
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