TypeScript 7 still requires duplicate Register augmentation for Start server-entry context

Which project does this relate to?

TanStack Start / React Start server entry types.

Describe the bug

Related to #7353.

With TypeScript 7.0.2 and TanStack Start 1.168.46, augmenting Register in @tanstack/router-core is not enough for the generated TanStack Start server entry. The generated server code imports Register from @tanstack/react-router.

Our request-context declaration contains both augmentations:

import '@tanstack/router-core'

declare module '@tanstack/router-core' {
  interface Register {
    server: { requestContext: MyRequestContext }
  }
}

declare module '@tanstack/react-router' {
  interface Register {
    server: { requestContext: MyRequestContext }
  }
}

The @tanstack/router-core augmentation is required for the TypeScript 7 owning-package rule. The @tanstack/react-router augmentation is still required by TanStack Start server-entry typing.

Complete minimal reproducer

The public reproducer from #7353 is:

https://github.com/alexander-zuev/riposte

Clone it and remove either one of the two Register augmentations. The server request-context type then falls back to BaseContext.

Steps to Reproduce the Bug

1. Use a TanStack Start app with the versions listed below.
2. Declare server.requestContext only in @tanstack/router-core.
3. Run the app type-check.
4. Observe that the generated server entry does not receive requestContext.

In our monorepo, removing only the @tanstack/react-router bridge produces:

apps/example-base/src/server.test.ts(40,12): error TS18048: 'options.context' is possibly 'undefined'.
apps/example-base/src/server.test.ts(40,29): error TS2339: Property 'requestId' does not exist on type 'BaseContext'.
apps/example-base/src/server.ts(99,78): error TS2353: Object literal may only specify known properties, and 'requestId' does not exist in type 'BaseContext'.

Restoring both augmentations makes the full workspace type-check pass: 13/13 tasks.

Expected behavior

The @tanstack/router-core augmentation should be sufficient, or TanStack Start should document that the @tanstack/react-router bridge is required.

A future TanStack release should allow removing the bridge without losing server.requestContext types.

Screenshots or Videos

Not applicable.

Platform

• Router / Start Version: @tanstack/react-start@1.168.46, @tanstack/react-router@1.170.29, @tanstack/router-core@1.171.24
• TypeScript: @typescript/native 7.0.2
• OS: Linux
• Bundler: Vite
• Bundler Version: Vite 8.2.1
• Package manager: pnpm 11.20.0
• Framework: TanStack Start

Additional context

The current workaround is intentionally kept in three application request-context declaration files:

• apps/example-base/src/shared/logging/server-request-context.types.ts
• apps/logistic/src/shared/logging/server-request-context.types.ts
• apps/utm/src/shared/logging/server-request-context.types.ts

The owning-package augmentation targets @tanstack/router-core. The second augmentation targets @tanstack/react-router because TanStack Start's generated server entry imports Register from that re-export.

Please consider updating the generated server-entry type to consume the owning Register, or document this required bridge. This issue is a follow-up with TypeScript 7 context to #7353.

Start with the generated TanStack Start server entry and the reproducer at alexander-zuev/riposte, then inspect the three declaration files listed in the issue. Remove the @tanstack/react-router augmentation and run the workspace type-check to trace why requestContext falls back to BaseContext. Done means the owning @tanstack/router-core augmentation is sufficient, or the required bridge is documented.