@msteams∕components-some-component∕src∕__generated__∕some-relay-compiler-artefact.ts

import someLiveResolver from "@msteams/some-live-resolver-package";

{
  "someLiveResolverBackedField": someLiveResolver as RelayLiveResolverFn<
    import("@msteams/some-core-package").LiveResolverContext
//  ^......................................................^ - type annotation literal, extracted by relay-compiler from @msteams/frameworks-relay/createRelayEnvironmentTask.ts
  >
}

@msteams∕frameworks-relay∕createRelayEnvironmentTask.ts

import { getLiveResolverContext } from "@msteams/some-core-package";

export function createRelayEnvironmentTask() {
  const store = new LiveResolverStore<
    import("@msteams/some-core-package").LiveResolverContext
//  ^......................................................^ - type annotation literal, extracted by relay-compiler here
  >(
    new RelayRecordSource(),
    { liveResolverContextProvider: getLiveResolverContext }
  )
  // ...
}

@msteams∕some-core-package∕index.ts

export interface LiveResolverContext {
  someService: SomeService;
}

export const getLiveResolverContext: () => LiveResolverContext = () => ({
  someService: new SomeService(),
})

@msteams∕some-live-resolver-package∕someLiveResolver.ts

export const someLiveResolver: RelayLiveResolverFn<
  import("@msteams/some-core-package").LiveResolverContext
//^......................................................^ - type annotation literal, written manually by dev
> = (context) => {
  // ...
}

To be clear, I don't mean safe all the way through relay, but safe in the sense that what is being passed to the store matches what the resolver functions would accept. (If still unclear, I'll rework the gist as a typescript playground sample.)

But as said, a naive approach would break down quickly when there's more than 1 store/context typing in the system.