Concraft is a morphosyntactic disambiguation library based on constrained conditional random fields [1].
A good example of how the library can be used is Concraft-pl, a morphosyntactic tagger for the Polish language.
[1] Jakub Waszczuk, "Harnessing the CRF complexity with domain-specific constraints. The case of morphosyntactic tagging of a highly inflected language.", in Proceedings of COLING 2012, Mumbai, India.