Game concept
Perpetual Hook
The game also links it as Perpetual Hooks.
From the game's encyclopedia
A Perpetual Hook is a Hook that you might have on a character who owes you a favor, or that you have manipulated to do your will.
They cannot be used to force someone to become your Agent in a Murder and do not provide a passive benefit (for that, a Strong Hook is necessary.)
Perpetual Hooks are not spent when used, but instead go on a cooldown before they can be used again.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Perpetual Hook is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Perpetual Hook is a Hook that you might have on a character who owes you a favor, or that you have manipulated to do your will." It is part of Hook. The game also links it as Perpetual Hooks. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.