  The Planning Domain Definition Language (PDDL) is the state-of-the-art
language for specifying planning problems in artificial intelligence research.
Writing and maintaining these planning problems, however, can be time-consuming
and error prone. To address this issue, we present myPDDL-a modular toolkit for
developing and manipulating PDDL domains and problems. To evaluate myPDDL, we
compare its features to existing knowledge engineering tools for PDDL. In a
user test, we additionally assess two of its modules, namely the syntax
highlighting feature and the type diagram generator. The users of syntax
highlighting detected 36% more errors than non-users in an erroneous domain
file. The average time on task for questions on a PDDL type hierarchy was
reduced by 48% when making the type diagram generator available. This implies
that myPDDL can support knowledge engineers well in the PDDL design and
analysis process.
