Executor
The scheduled task, hook or build step that actually invokes a rule. A rule without one is a proposal.
An executor is whatever actually calls a rule — a scheduled task, a git hook, a build step. Rules with no named executor do not run and produce no error when they do not, which is why they decay silently.
Definition
The concrete mechanism that invokes a rule: a scheduled task, a git hook, a build step, a session-start script. Not the rule itself and not the person who wrote it.
In practice
Every repeated rule in this system names its executor on the same line as the rule. If none can be named, the item is labelled proposal, not rule.
The test is blunt: if everyone forgets this exists, what still runs it? One documented failure ran 84 days on the answer "nothing".
executor: weekly scheduled task, Friday 07:00 — fails loudly
See also
a-rule-without-an-executor · standing-mandate