Script Debugger
Used by 3 peoplelatenightsw.com ↗

“And, while working on AppleScript support in our apps, Script Debugger is amazingly useful.”
Timothy Wood Interview, CTO and co-founder (The Omni Group) · via Uses This 
“I also write software documentation, such as the online help for Script Debugger.”
Matt Neuburg Interview, Developer, writer, contributing editor (TidBITS) · via Uses This