idea?[idea:1]The semantics of an idea is taken from the default Doom Emacs TODO keywords, one of which is IDEA.
An idea in a rookery should be conceptualized as an atomic note, which is why each idea is given its own standalone page. As with notes in other Zettelkasten-inspired systsems, ideas that link to each other produce backlinks
In addition to this sense of an idea (as a ‘Zettel’, or note), it can also be the basis for a ‘todo’ item (as an Org-mode TODO). This is one of the reasons that rookery ships the #todo function as syntactic sugar for an #idea with a "todo" tag. Though there is no inbuilt sense in which one idea can depend on or be blocked by another, you can create a stronger dependency system over tags, i.e. using a blockedby:xxx convention.