Meta's Secret ‘Watermelon’ AI Model Reportedly Matches OpenAI's GPT-5.5

Meta CEO Mark Zuckerberg has accelerated the company's push into generative AI in recent years, establishing a superintelligence lab and expanding investment in talent and computing infrastructure to narrow the gap with OpenAI. If “Watermelon” reaches flagship-model performance, it could affect both the enterprise AI market and competition among open-source models. Meta has not disclosed the amount invested.

As of July 19, 2026, Meta Superintelligence Labs chief Alexandr Wang said the “Watermelon” model under development had matched OpenAI GPT-5.5 in benchmark scores. Its training compute was one order of magnitude greater than that of its predecessor, “Avocado.” Meta has not disclosed the model's parameters, full test results, formal release date or commercialization timetable.