Problem
The MCP SDK's ServerCapabilitiesSchema (Zod) strips unknown root-level keys. Custom capabilities like io.modelcontextprotocol/ui must be declared under experimental to survive the schema validation.
Fix
CapabilityClassifier: Check both capabilities['io.modelcontextprotocol/ui'] and capabilities['experimental']['io.modelcontextprotocol/ui']SnapshotBuilder: Same fallback for extension version extraction- Add tests for experimental fallback scenarios
Problem
The MCP SDK's
ServerCapabilitiesSchema(Zod) strips unknown root-level keys. Custom capabilities likeio.modelcontextprotocol/uimust be declared underexperimentalto survive the schema validation.Fix
CapabilityClassifier: Check bothcapabilities['io.modelcontextprotocol/ui']andcapabilities['experimental']['io.modelcontextprotocol/ui']SnapshotBuilder: Same fallback for extension version extraction