  The Annotation Graph Toolkit is a collection of software supporting the
development of annotation tools based on the annotation graph model. The
toolkit includes application programming interfaces for manipulating annotation
graph data and for importing data from other formats. There are interfaces for
the scripting languages Tcl and Python, a database interface, specialized
graphical user interfaces for a variety of annotation tasks, and several sample
applications. This paper describes all the toolkit components for the benefit
of would-be application developers.
