Add convert_document API support

[ipfans]

Thanks so much for your stellar work here. I noticed the convert_document API isn't yet implemented when using the tool. While we can append file contents manually, that works smoothly for txt but takes a bit more effort for pdf or csv formats. Having that API would save us quite a bit of time and heavy lifting. Would it be possible to add convert_document support in a future release? That would take the tool to the next level. I appreciate you putting this together - it will be a huge help once we get convert_document up and running.