Resolution, Initiative, and Reactions

Resolution, Initiative, and Reactions
Tick resolution
Each tick runs one loop over every actor, in initiative order:
Actor action processing. Does the actor have an action in progress?
No - select the next action (monsters: from the profile's ranked triggers; player: input - the game stops until they commit) and process its first tick. A zero-prep action flows straight through to the next phase.
Yes - process the current tick of the PER cycle.
Reaction collection. After the actor's processing, loop the other actors: did this tick trigger a reaction? If yes, add it to the queue - an actor may collect multiple reactions in the same tick. The reactor-side gate applies at collection: an actor in its own exec adds nothing (it is committed, not observing).
Reaction pass. Loop the reaction queue in initiative order:
An actor with several queued reactions evaluates them and uses the best one for the current circumstances; the rest are discarded. Monsters rank by profile; the player is offered the choice.
If the actor executes the reaction: pause or cancel their current action (if any), per that action's interruptibility, then process the first tick of the reaction's own PER cycle. A short reaction may complete its exec within this tick and spend subsequent ticks in recover.
Movement is not a special phase - it is an action like any other and runs through the same actor loop. Within a movement action, "leaving" reaction triggers queue before "entering" triggers; initiative breaks ties within each kind.
Deterministic, seeded, logged. This is what makes fights replayable for debugging and tuning.
Initiative
Rolled at combat start (Perception or Stealth style, as in Pathfinder), fixed for the whole fight.
Used as priority for same-tick, world-affecting resolutions only (actor order, reactions, movement events) - not for internal phase transitions.
Tiebreakers: dex, then level, then PCs-over-monsters, then a coin flip pre-rolled once per combat (so identical actors stay consistent all fight).
Initiative as a speed stat: a small random jitter is added to PER cycles; initiative reduces prep and recover time (never exec - exec durations stay consistent so active windows remain readable). High initiative therefore produces more actions over a fight. The jitter is seeded per combat so replays reproduce.
Reactions
Reactions are short actions taken out of sequence, triggered by observing another actor's phase.
Can I react at all? - gated by your own phase:
My phase
React?
Cost
Prep
Yes
Pauses or cancels my prep, per the action's interruptibility
Exec
No
Committed - this is the point
Recover
Yes
The reaction's own PER handles the cost
What can my reaction do? - gated by the observed target's phase:
Observed phase
What a reaction can do
Prep
Can cancel the target's action (interrupt the windup). Knowledge-gated: only actors who can read prep as prep can target it.
Exec
Can mitigate the action (reduce or disrupt its effect) - or do something entirely unrelated.
Recover
Cannot affect the completed action at all - but the target is vulnerable, so this is an exploit window: act while they wind down.
Reactions never need to counter the triggering action. They trigger on phase events, not as restricted counters: a magehunter reacts to a mage's casting by throwing a knife; a mage under attack reacts by casting shield for extra AC.
Reactor cost - the reaction's own PER. The tax lives in the reaction's own cycle, never the parent action's. Reactions should be built with short or zero prep and short exec; the recover is the throttle - pad it to tax use. This composes with the exploit window: reaction spam leaves the actor in a long recover, where enemies can take advantage.
Interruptibility (pause vs cancel). When an actor reacts, what happens to their in-progress action is an action property: actions that demand deep concentration are cancellable on reaction; lighter actions pause and resume once the reaction fully completes (including its recover). Set per action, like any other parameter.
Baiting is a core player skill: a monster that has already spent its reaction window has no answer to a maneuver.