failed-precondition
what this Firebase error means
How it shows up
FirebaseError: [code=failed-precondition]: The query requires an index. You can create it here: https://console.firebase.google.com/...
What it means
Firestore rejected the operation because the system is not in the state the operation needs. A common case is a query that needs a composite index that does not exist yet.
The usual cause in an AI-built app
AI-generated queries often combine a where filter with an orderBy or range filter on another field. That needs a composite index, which Firestore does not create for you.
Check this first
Open the link in the full error message, which fills in the missing index in the Firebase console, and check its fields before you create it.