Thanks Christian,
I'm not sure I understand how to make use of this. My tool dependency is described in an XML file which is in the same source directory as the tool xml and python files. The tool xml file contains:
<requirement type="package" version="1.0">python_nltk_tools</requirement>
and the tool_dependencies.xml file contains the definition:
<tool_dependency>
<package name="python_nltk_tools" version="1.0">
...
how do I tell planemo to tell galaxy that it should refer to this tool dependency file to resolve the requirement? At the moment it's loading all of the tools but doesn't seem to be concerned that the requirement isn't met.
Thanks for your help.
Steve