Woofun AI reports that Meta's stock price narrowed its decline to 0.6% following the announcement of its paid AI developer model, Muse Spark 1.1. This competitively capable agent and coding model demonstrates performance comparable to GPT-5.5 and Opus-4.8 in multiple agent evaluations. The model is immediately accessible through the new Meta Model API and the Meta AI platform, with CEO Zuckerberg stating that planned pricing will be lower than competitors.