Describes how things should be - how to get there is "under the hood" and is implied in the description.

Example from SAGE Cfengine booklet:

File ownership and protection specifications:

files: /usr/local/bin owner=root group=bin mode=755 action=fixall recurse=1

Cfengine's declarative languages is used to write configuration "policy rules", or "promises" of how the system should be configured.