tRPC v11

The decisions tRPC forces and how to settle them, written so an agent applies them while writing or reviewing code. Every rule names the wrong default it corrects; there is no rule for what the model already gets right.

Pinned to tRPC v11, verified against 11.18.0 (2026-06-17). There is no v12 — but several APIs here carry @deprecated … will be removed in v12 and still ship today. Peers: typescript >=5.7.2, @tanstack/react-query ^5.80.3, react >=18.2.0.

When to Apply

Use this skill when:

• Code imports initTRPC, createTRPCContext, createTRPCOptionsProxy, createTRPCReact, createTRPCClient, httpBatchLink, httpSubscriptionLink, splitLink, fetchRequestHandler, createCallerFactory, or TRPCError — or defines procedures with .input() / .output() / .use() / .query() / .mutation() / .subscription()
• The user says "everything types as any", "invalidation isn't working", "contextMap[utilName] is not a function", "the transformer property moved", "414 / 413 on the dashboard", "subscriptions won't connect", "the prefetch isn't hydrating", or "it 404s every procedure"
• Migrating a codebase from tRPC v10, or reviewing tRPC code written against v10-era examples — the highest-yield moment, because the recommended React client changed and stale code often still compiles
• Adding the first subscription, the first file upload, or the first RSC prefetch to an existing router — each crosses into a surface where v11 replaced the v10 approach outright
• Reviewing a batched client as the app grows, where the uncapped defaults turn into intermittent production failures

This skill is NOT for: