Describe the feature or problem you’d like to solve

The get_file_contents tool currently returns file contents in base64. This matches the backing API, but it'd be nice to have a non-base64 option for this. The corresponding create_or_update_file tool accept plaintext, even though the backing API only allows base64.

Proposed solution

This would create interface consistency and probably lead to better model performance with the tool.

Additional context

I'm happy to send a PR for this if there's a recommended approach I should take!