6.1 Tag Inheritance

Tags make use of the hierarchical structure of outline trees. If a heading has a certain tag, all subheadings inherit the tag as well. For example, in the list

* Meeting with the French group      :work:
** Summary by Frank                  :boss:notes:
*** TODO Prepare slides for him      :action:

the final heading has the tags ‘work’, ‘boss’, ‘notes’, and ‘action’ even though the final heading is not explicitly marked with those tags. You can also set tags that all entries in a file should inherit just as if these tags were defined in a hypothetical level zero that surrounds the entire file. Use a line like this⁵¹

#+FILETAGS: :Peter:Boss:Secret:

To limit tag inheritance to specific tags, or to turn it off entirely, use the variables org-use-tag-inheritance and org-tags-exclude-from-inheritance.

When a headline matches during a tags search while tag inheritance is turned on, all the sublevels in the same tree—for a simple match form—match as well⁵². The list of matches may then become very long. If you only want to see the first tags match in a subtree, configure the variable org-tags-match-list-sublevels (not recommended).

Tag inheritance is relevant when the agenda search tries to match a tag, either in the tags or tags-todo agenda types. In other agenda types, org-use-tag-inheritance has no effect. Still, you may want to have your tags correctly set in the agenda, so that tag filtering works fine, with inherited tags. Set org-agenda-use-tag-inheritance to control this: the default value includes all agenda types, but setting this to nil can really speed up agenda generation.