The Vanishing Glass

Did you notice?

A zoo and a bored snake establish that odd things happen around the boy and that the household punishes him for them. The glass vanishing is a power leak, played as a mishap. Notice how little anyone explains. The book trusts a reptile conversation more than a lecture.

Foreshadowing

Talking to snakes becomes a feared skill, not a party trick, once the school decides what that talent means. The second book is the one that picks this thread up and makes it political.

This echo points at book 2. It is a reading note, not a quote.