Firebase Ai Logic Basics

This gets you up and running with Firebase AI Logic, which lets you call Gemini models directly from client apps without managing a backend. It covers the full setup flow including the critical npx firebase-tools init ailogic command that actually provisions the service, multimodal input handling for images and PDFs, structured JSON output, and streaming responses. The docs are clear about App Check being mandatory for production to prevent quota abuse, and they emphasize using the Gemini Developer API by default since it has a free tier. One nice touch is the hybrid on-device mode for web that automatically falls back to cloud when Gemini Nano isn't available locally.