Chatkit invalid upload file types

Hey all, thanks for laying everything out clearly.

Since uploads are enabled and other file types (like PDFs/images) work, but .csv / .xlsx are being rejected with chatkit.file_upload_type_rejected, this is likely happening at the ChatKit upload layer before your workflow runs.

Before we escalate this internally, we’ll need a bit more concrete evidence so engineering can investigate properly. Could you share the request ID from one of the failed /v1/chatkit/files calls, along with the exact MIME type being sent (you can check the Content-Type header in the network tab)? Also, let us know whether you're using the OpenAI-hosted ChatKit endpoint or running your own server, and roughly when (including timezone) the failure occurred.

Once we have that, we can package this properly for escalation.