@Karishma Nanda Any input/output tokens will be charged additionally apart from inference cost for assistant.
Ref: https://learn.microsoft.com/en-us/azure/ai-services/openai/how-to/code-interpreter?tabs=python
For files, Assistants use the same API for file upload as fine-tuning. So, the limits for files are applicable. I don't think there is a charge to store the files, similar to fine tuning files. I hope this helps!!