Moves MCP App results onto explicit runtime schemas so hosts can distinguish model-visible output from widget-only graph data.
- advertises output schemas for structured tools
- validates API, session, and widget boundaries instead of asserting response types
- marks additive app writes as non-destructive and removes redundant widget typing
Verified with MCP typecheck, 42 unit tests, and the production widget build. Claude Desktop host validation is in progress against a temporary tunnel.