The MOO source-level debugger is an extension to the LambdaMOO server providing an interface which is (hopefully) suitable for writing an in-MOO source-level debugger. It has now reached a production level of stability. This is solely a server patch providing several additional built-ins and does not contain any MOO-code. Steve Caron has written a $debug, implementing the MOO-code end of a MOO source-level debugger in an object based on the generic editor.
You can also read the documentation..
Get the SLD patch.
Get the $debug object.
The MOO Direct Stack Access is an older server patch providing some, but not all, of the functionality seen in the MOO SLD. It allows direct access to the variables in other executing tasks, both to read and to change them. It does not include the cool step-by-step execution available in the SLD. This distribution of the DSA functions is much less "intrusive", requiring only one slight change in the MOO source itself. If you get the SLD, the DSA is redundant and will not install properly.
Get the DSA extension.