```ts
/**
 * Returns the names standing directly under a stated head in the store.
 * @param store - An object where keys are names joined by full stops.
 * @param head - The head name to filter under.
 * @returns An array of names directly under the head, without the head and its stop.
 */
export function keyPath(store: Record<string, string>, head: string): string[] {
  const headLength = head.length + 1; // Include the dot
  return Object.keys(store)
    .filter(key => key.startsWith(head) && key[headLength] === '.')
    .map(key => key.slice(headLength + 1));
}
```