[galaxy-dev] Workflow Compatibility

Hi Everyone, Would anyone be able to tell me the conditions which would make a tool non-workflow compatible? I have a tool that imports files from a third party application and auto-detects the file format. There is also the option to upload multiple files at once so the tool always uploads at least two files. From what I have described can anyone see why this tool would not be able to send one of its files to the next tool in the chain, ex. a text manipulation tool? Thanks, Katherine