Ask for self-contained code to avoid a broken preview

The prompt

Always state "no external network requests, no CDN imports, no build step" up front — most live-preview sandboxes block outbound requests, so any prompt that omits this ends up generating code that renders blank.

Expected result

A generated artifact that renders correctly on the first try in a sandboxed preview, instead of a blank screen from a blocked external request.

Why it works

Sandboxed preview panels typically block network calls entirely, so a prompt that does not rule out external imports leaves the model free to reach for a CDN library that will silently fail.