When designing or consuming client/server APIs, keep the contract explicit and prevent duplicate logic/types from drifting.

Apply this standard:

• Single source of truth: If the backend persists/owns a value, the UI should display it directly—avoid re-adding client fallbacks that recreate the same logic.
• No contract drift: Don’t export additional request/type wrappers that duplicate the method’s already-type-checked signature unless they add real behavior/guarantees.
• Clear protocol boundaries: Distinguish wire-format types from internal/extended types and document mappings intentionally.
• Typed surfaces > generic fallbacks: Provide a dedicated typed callback/API for each notification/method; use a generic dispatcher only for untyped/escape-hatch cases.
• Centralize API access patterns: If multiple call sites repeat getClient() + thin wrappers, centralize into a shared utility/hook to keep calling semantics consistent.

Example patterns:

• Don’t reintroduce UI fallback when the server is authoritative:

  export function getSessionDisplayName(session: Session): string {
  return session.name || DEFAULT_CHAT_TITLE;
  }
  

• Avoid exporting a redundant request type when the method signature already validates:

  // Prefer relying on GooseClient.initialize(...) typing
  // instead of maintaining GooseInitializeRequest that can diverge.
  

• Keep notifications typed and route generically only as fallback:

  export interface GooseExtNotifications {
  unstable_sessionUpdate?: (n: GooseSessionNotification_unstable) => Promise<void>;
  }