Hello, When adding a new tool, we used a cheetah'ed shell script defined in the <configfiles> tags of the tool's xml file. To get the absolute path of an external script located in the tools directory, I used the following code in the <configfile> script: ${ os.getcwd() }/${ $__app__.config.tool_path }/toolsubdir/scriptname.sh When I tried the new tool, I got an error message. Here are the last lines: File "/g/funcgen/galaxy/lib/galaxy/tools/parameters/basic.py", line 681, in value_from_basic if isinstance( value, dict ) and value["__class__"] == "UnvalidatedValue": KeyError: '__class__' Therefore I slightly modified the file basic.py. I replaced the line 681: if isinstance( value, dict ) and value["__class__"] == "UnvalidatedValue": by: if isinstance( value, dict ) and getattr(value, "__class__") == "UnvalidatedValue": and it works fine now. I fail to see why the original code didn't work though. Hope that helps. Regards, L-A