MCP App (Apps SDK / widgets) metadata

MCP Apps can ship UI surfaces (widgets) alongside tools. Your widget bundle and tool/resource metadata should stay aligned so the host can load the correct UI for a given tool or resource URI.

Host–widget logging

The MCP App host can send structured diagnostic events to embedded widgets via postMessage (for example type: "agentsyx-log", source: "mcp-host", plus level, message, and optional context). Widgets that listen can surface host-side logs in their own debug UIs—especially useful on mobile where browser devtools are limited. Any MCP App widget running inside Agentsyx can use this pattern.

Directory and review considerations

OpenAI and Anthropic expect a coherent product surface (web SaaS + optional chat). At the metadata level, keep names, descriptions, and privacy-related disclosures consistent across your portal, MCP server, and any embedded UI.

This page stays reference-level; submission checklists live with your release process.