Let me clarify -- my .pyt calls other custom modules, and if there is a syntax error in one of these modules, a red X appears (rendering the toolbox unusable) and the message is "no syntax errors" even though there is one, though not in the .pyt. Shouldn't the debugger be able to point me to the file with the error? My particular syntax error arose because I am using GitHub and had a merge conflict, which wrote a bunch of lines like "<<<<<<HEAD" as guidance for manual edits. Since one of the custom module scripts had the error, compiling the .pyt worked fine, but as the module is imported, opening the toolbox in ArcGIS won't work. Could there be more direction to errors in imported modules? Otherwise, debugging becomes difficult.