{"server":"com.sigistry/plugin-catalog","count":1,"changes":[{"tool":"check_mcp_app","kind":"added","observed_at":"2026-10-03T00:02:08.042Z","fields":[],"description_before":null,"description_after":"Get the Sigistry MCP App safety criteria to audit an MCP App (MCP Apps / SEP-1865: a tool that returns an interactive ui:// HTML resource the host renders in a sandboxed iframe) BEFORE shipping it. Returns two groups of checks: spec conformance (ui:// scheme, the text/html;profile=mcp-app mimeType, tool-to-UI linkage via _meta.ui.resourceUri, a text fallback, visibility values, and CSP coverage of external origins) and security hygiene the iframe sandbox does not cover (unsafe DOM sinks, embedded secrets, host-message origin handling, remote scripts). Call this when the user is building or reviewing an MCP App; then apply each check to the app source you have in context and report findings. Nothing is sent to this server; an interactive browser version is at https://sigistry.com/mcp-app-checker.","description_similarity":null,"before_hash":null,"after_hash":"dca3dda2a3a1cc2db2b12d0a9ad1b99e"}],"next_before":null,"next_actions":[]}