CVST is a tool that allows for cross-dialect development across Smalltalk environments like Squeak and VisualWorks. It acts as a bridge between Smalltalk projects and the CVS version control system, allowing Smalltalk code to be version controlled with CVS. CVST works by mapping Smalltalk projects containing classes and packages to the directory structure used by CVS. It handles operations like updating code from CVS, committing changes to CVS, and merging changes when conflicts occur. The goal of CVST is to enable collaborative development across Smalltalk dialects and with other languages using a file-based version control system like CVS.