Back to the HomePage.

PDDL support of Fast Downward

On this page, we collect information regarding the subset of PDDL that is supported by Fast Downward. So far, this is not an exhaustive list, but we hope that it will become more comprehensive over time. If you want to contribute information or have a question, please get in touch! (See the contact information on the HomePage.)

General information

Fast Downward aims to support PDDL 2.2 level 1 plus the :action-costs requirement from PDDL 3.1. For a definition of the various "levels" of PDDL, see p. 63 the paper "PDDL2.1: An Extension to PDDL for Expressing Temporal Planning Domains" by Maria Fox and Derek Long (JAIR 20:61-124, 2003).

This means that the following major parts of PDDL are unsupported:

Expressed positively, this means that the following features of PDDL are supported beyond basic STRIPS, with some limitations mentioned below:


These limitations are somewhat likely to be lifted in the future, but progress is slow.


Some features are supported in theory, but currently affected by bugs. In addition to the issues with conditional effects mentioned above which are somewhere between a bug and a missing feature, we are currently aware of the following bugs:

The above list might be outdated by the time you are reading this. Follow the links to the issue tracker to be sure. If the list is not up to date, it would be great if you could send us a note so that we can remedy this. (See contact information on HomePage.)

FastDownward: PddlSupport (last edited 2015-11-12 17:02:36 by MalteHelmert)