Do you have to tip in Dominican Republic all-inclusive?

Inquiring minds want to know: Is tipping customary in Dominican Republic's all-inclusive resorts? I've heard varying opinions on this matter, and I'm curious to get a professional's take. Given the culture and etiquette surrounding tipping in different countries, I'm wondering if the same applies in Dominican Republic's all-inclusive vacation spots. Should one tip for excellent service, or is it already factored into the inclusive package? I'd appreciate your insights on this matter, as I'm planning a trip and want to ensure I adhere to local customs.