The Community Z Tools (CZT) project is an open-source Java framework for building formal methods tools for Z and Z dialects. It also includes a set of tools for parsing, typechecking, transforming and printing standard Z specifications in LATEX, Unicode or XML formats. This paper gives an overview of the CZT framework, including an introduction to its visitor design pattern that makes it possible to write new Z transformation tools in just a few lines of Java code. The paper also discusses several problems and challenges that arose when attempting to build tools based on the ISO Standard for Z.