I wrote a simple tool to edit MTM Test Plans outside of MTM .. Is there a licensing issue with non-MSDN users using it?

If I write tools using the TFS API, are there licensing issues with non-MSDN users using those tools? 

Specifically MTM is a horrible tool, so I rewritten it using the TFS API. Creating Test Cases, linking to Suites and Plans, updating Pass/ Fail, multi-select, batch updates, changed how Test Results works.

I would like to propose we send this our Outsource Team as now we have to painfully export Test Cases to Excel and manually enter results.