Pylint is the most popular Python source code analyzer which looks for programming errors, helps enforce a coding standard and sniffs for some code smells. It is possible to write plugins to add your own checks, for example enforce all documentation strings to be enclosed with 3 double quotes! This presentation will focus on how the pylint plugin system works, how to examine AST tree of a piece of code and create a minimalistic plugin from scratch. It will also examine couple of plugins that are used in the Kiwi TCMS project.