I worked with this module extensively when I was trying to implement a web site testing application. The module authors were well-intentioned and anticipated an unmet need. However, the module is not worth using now that HTTP::WebTest is available.
The HTTP::Monkeywrency module has numerous bugs; several of the documented features simply don't work and were obviously never tested. I sent the authors two bugfix patches; my e-mails were ignored. After a few weeks of wasted effort I ditched HTTP::Monkeywrench and wrote HTTP::WebTest.
Ilya Martynov is now actively maintaining HTTP::WebTest and he has done a complete rewrite of my code, adding numerous features while maintaining the simplicity of the core features. The authors of HTTP::Monkeywrench have never made any attempt to maintain it. It is a dead module.