We’re seeing this a bunch too, even in the playground. Assistants API is completely broken and usable currently.
Here are some threads for the OpenAI staff to investigate further:
https://platform.openai.com/assistants/thread_WxDDVWF95H2kjsYogl0SahWm
https://platform.openai.com/assistants/thread_rngP0aByAw2RgMtZbRVUY8ae
https://platform.openai.com/assistants/thread_oFNPayCVDRAHX6OoJ4BXS3jr
https://platform.openai.com/assistants/thread_IYrlC9bUnnKenKocM1puFMTc
https://platform.openai.com/assistants/thread_LbVYHURutLnWStuaMc2jhBQA
https://platform.openai.com/assistants/thread_HWszOxiToeEb4Z2DGf8zIdqO
https://platform.openai.com/assistants/thread_uXDdGkob991TTvmLlH1N6891
https://platform.openai.com/assistants/thread_NB3y3zelorqLnd8aZ9AtWSRv
https://platform.openai.com/assistants/thread_AYbfM7fGW83e3bRmM7lGOSfV