controller.ts

import * as C from '@lit-labs/context';

class S<T extends C.ContextKey<unknown, unknown>> {
  constructor(
    public host: HTMLElement,
    public context: T,
    public provider: C.ContextType<T>,
  ) {}
}

interface P {
  hi: 'there'
}

const el = new HTMLElement();
const c = C.createContext<P>('hi');
const s = new S(el, c, {});

s.provider.hi;

const d = C.createContext<number>('there');

new S(el, d, 2);