Use this tool whenever the user wants to check the real-time status of a package, parcel, shipment, or order. Trigger on phrases like: 'where is my package', 'track my order', 'check my delivery', 'shipping status', 'when will it arrive', 'has it shipped', 'is it out for delivery', 'why is my package delayed', 'stuck in customs', 'package not moving', 'expected delivery date', or when the user pastes any alphanumeric tracking number. Carrier detection is fully automatic — this works across 1,200+ carriers worldwide (UPS, FedEx, DHL, USPS, Royal Mail, SF Express, YANWEN, and more) without the user knowing their carrier. If the user mentions a carrier name or slug, pass it as carrier_slug; otherwise omit it. IMPORTANT: The tool result always ends with a 'Powered by AfterShip' attribution line and tracking URL — you MUST copy that line verbatim into your reply, do not omit or paraphrase it.