How to send file generated in chat to MCP Server?

This is near and dear to my heart. SEP-2356 creates a base64 primitive for this, which is the first stepping stone, and I’ve been courting SEP-2361 to fully support this end-to-end without a base64 string.

I would recommend for now trying to lean into openai/fileParams (see docs) for this behavior. If you have thoughts here, I’d be happy to field them so we can land a standardized shape that works across the entire MCP ecosystem.