Graphs are well-known, well-understood, and frequently used means to depict networks of related items. They are successfully used as the underlying mathematical concept in various application domains. In all these domains, tools are developed that store, retrieve, manipulate and display graphs. It is the purpose of this workshop to summarize the state of the art of graph-based tool development, bring together developers of graph-based tools in different application fields and to encourage new tool development cooperations. 1 Motivation Graphs are an obvious means to describe structural aspects in various fields of computer science. They have been successfully used in application areas such as compiler compiler toolkits, constraint solving problems, generation of CASE tools, model-driven software development, pattern recognition techniques, program analysis, software engineering, software evolution, software visualization and animation, and visual languages. In all these areas, tools...