TanStack Start server-entry requestContext type ignores @tanstack/react-start Register augmentation

Which project does this relate to?

TanStack Start / React Start server entry types.

Describe the bug

The current Server Entry Point docs say request context should be typed by augmenting @tanstack/react-start:

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

With that in place, this should typecheck:

import handler, { createServerEntry } from '@tanstack/react-start/server-entry'

export default createServerEntry({
  fetch(request, env, ctx) {
    return handler.fetch(request, {
      context: { deps: createAppDeps(env, ctx) },
    })
  },
})

In our app, TypeScript reports:

Object literal may only specify known properties, and deps does not exist in type BaseContext.

The reason appears to be that @tanstack/react-start/server-entry types ServerEntry using Register from @tanstack/react-router:

import type { Register } from '@tanstack/react-router'
export type ServerEntry = { fetch: RequestHandler<Register> }

So the documented @tanstack/react-start augmentation is not visible to serverEntry.fetch(...); the context type falls back to BaseContext.

Current workaround

We have to duplicate the same server.requestContext augmentation for both modules:

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

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

This typechecks, but it seems inconsistent with the public docs and leaks Start-specific server context into the router module augmentation.

Expected behavior

The documented @tanstack/react-start augmentation should be sufficient for handler.fetch(request, { context }) / createServerEntry(...).

Alternatively, the docs should mention that @tanstack/react-router also needs to be augmented for the server-entry fetch type.

Versions

@tanstack/react-start: 1.167.59
@tanstack/start-server-core: 1.167.26
@tanstack/start-client-core: 1.168.1
@tanstack/react-router: 1.169.1
TypeScript: 5.9.3

Start at the @tanstack/react-start/server-entry types and compare their ServerEntry/RequestHandler registration with the Server Entry Point documentation. Reproduce the example using only the documented @tanstack/react-start augmentation, then verify that handler.fetch(request, { context }) and createServerEntry(...) accept the custom request context without duplicating the @tanstack/react-router augmentation.