Meta's rapid iteration on the Muse Spark family, with version 1.3 shipping September 2 via the Meta Model API and Muse Code, stands as the main driver of trader expectations for a 1.4+ release. The update delivered measurable gains in long-horizon agentic workflows and coding efficiency, using fewer tool calls and tokens than 1.2 while improving calibration on complex tasks. Mark Zuckerberg has highlighted the model's frontier performance at low cost and teased a larger "Watermelon" model plus open-weights releases ahead, consistent with Meta Superintelligence Labs' four-model cadence since April. No confirmed timeline or developer conference anchors the next step, leaving market sentiment anchored to historical release spacing, ongoing API adoption data, and any fresh internal progress signals from Meta.