The router previously created its own initTRPC without superjson while the app router uses the shared transformer-enabled instance — a wire transformer mismatch that corrupts inputs (audit finding A10). Procedures now build on @repo/core-shared/trpc/init's t; a real client+fetch-adapter round-trip test pins Date revival through appRouter-style mounting. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>