How do you stop AI coding tools from installing an npm package for literally everything?

Every time I ask AI for a quick code snippet, its default reaction is to tell me to npm install a brand new library even for basic utility stuff like array formatting or date math.

Before you know it the codebase is bloated with small single purpose packages that nobody wants to maintain. We already have solid built in helpers in our main codebase but the model completely ignores them unless I spell it out every single time.

How are you nudging your AI tools to look at what's already in the repo before pulling in extra dependencies?