rules

The system. What a character is made of, what dice decide, and how levels work.

Everything a character is made of is declared here. Required: attributes, resources, progression, and vitalResource. Everything else is optional.

Death

Reaching a resource floor runs its onDepleted effects. Death follows only if the creature is still at the floor afterwards and the resource is vitalResource.

"onDepleted": [ { "heal": { "target": { "ref": "actor.id" }, "amount": 1 } },
                 { "applyCondition": { "target": { "ref": "actor.id" },
                                       "condition": "downed" } } ]

means stabilised, not killed.

The order stats are worked out in

Attributes, then modifiers, then resource limits, then derived stats. Each step sees the ones before it. Modifiers see only their own attribute value. Derived stats also see equipment and active conditions. A resource limit cannot reference a derived stat.

Getting allies

dispositionBands maps a disposition number onto a stance, highest matching band first. The default has only neutral and hostile. Add a band above zero for an NPC to fight on your side.

rules`rules`

Field	Type	Req	Default	What it does
`attributes`	object[]	yes		What a character is made of. At least one is required.
`resources`	object[]	yes		Pools that go up and down. Hit points and focus are both just resources.
`derivedStats`	object[]		`[]`	Numbers computed from attributes, gear, and conditions.
`damageTypes`	object[]		`[]`	The kinds of damage that exist. Resistance and immunity are written against these.
`conditions`	object[]		`[]`	States a creature can be in, with what they do while they last.
`actionTypes`	object[]		`[]`	The action economy. Each type declares how many a creature gets per turn.
`equipmentSlots`	object[]		`[]`	Where gear goes, and how many items each place holds.
`itemProperties`	object[]		`[]`	Reusable tags on items that carry stat modifiers.
`masteryTiers`	object[]		`[]`	Named skill bands, so a requirement can ask for adept rather than rank 5.
`rests`	object[]		`[]`	The ways a party recovers, and what each costs in time.
`resolution`	object		`{}`	The dice convention. What a check rolls, what crits, how results round.
`progression`	object	yes		The level curve and what each level grants. Required.
`savingThrows`	object[]		`[]`	The saves that exist, each governed by an attribute.
`sizes`	object[]		`[]`	Creature sizes, with the space they take and how far they reach.
`creatureTypes`	object[]		`[]`	Broad kinds of creature, for gating and description.
`senses`	object[]		`[]`	How creatures notice each other. Sight, scent, hearing, or anything you invent.
`stances`	object[]		`[]`	Postures a creature can take, trading speed for concealment or the reverse.
`movementModes`	object[]		`[]`	Ways of moving, each with a base speed and a terrain multiplier.
`languages`	object[]		`[]`	Languages that exist. Creatures list which they speak.
`alignments`	object[]		`[]`	Moral or factional labels. Carried and gateable, never enforced.
`opportunities`	object[]		`[]`	Reactions the rules grant everyone, such as a parting blow.
`coverTypes`	object[]		`[]`	Degrees of cover and what each is worth on defence.
`spellcasting`	object		`{}`	Slots or points, concentration, components, and rituals.
`perception`	object		`{}`	Which sense counts as sight, and the defaults perception runs on.
`temperament`	object		`{}`	What creatures do unprompted: wandering, giving chase, and giving up.
`currency`	object		`{}`	What money is called and whether it can go negative.
`vitalResource`	rules.resources	yes		The resource whose floor means death. Required.
`initiativeStat`	rules.derivedStats			Derived stat rolled for turn order. Without one, order is by id.
`defaultSize`	rules.sizes			Size given to a creature that names none.
`defaultMovementMode`	rules.movementModes			Movement mode used when a creature names none.
`interactionRange`	object		`{}`	How close you must be to talk to someone or reach a thing.
`search`	object		`{}`	How far a search finds traps and how close disarming needs you.
`dispositionBands`	object[]		`[{"id":"neutral","atLeast":0,"stance":"ne…`	Disposition numbers to stances. A band above 0 is the only way to get allies.
`extra`	{ string: any }		`{}`	Open bag of your own data on the ruleset. Read it back with a ref path.

attributes`rules.attributes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the attribute, used as actor.attr.<id>.
`name`	string	yes		Display name.
`abbrev`	string	yes		Short form for tight displays, one to six characters.
`description`	string		`""`	What this attribute covers. Author and player facing.
`min`	number		`1`	Lowest value character creation and effects may take it to.
`max`	number		`20`	Highest value it may reach.
`default`	number		`10`	Starting value before creation spends any points.
`modifier`	expression	yes		Formula turning the raw value into a modifier. Sees only value.

resources`rules.resources`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the resource, used as actor.res.<id>.
`name`	string	yes		Display name.
`description`	string		`""`	What the pool represents.
`max`	expression	yes		Formula for the ceiling. May read attributes, modifiers, and level.
`min`	expression		`0`	Formula for the floor. Reaching it runs onDepleted.
`initial`	expression			Formula for the starting value. Defaults to the maximum.
`restoreOnShortRest`	number		`0`	Fraction of the maximum a short rest returns, 0 to 1.
`restoreOnLongRest`	number		`1`	Fraction of the maximum a long rest returns, 0 to 1.
`onDepleted`	effect[]		`[]`	What happens at the floor. Death is these effects on the vital resource.

derivedStats`rules.derivedStats`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the stat, used as actor.derived.<id>.
`name`	string	yes		Display name.
`description`	string		`""`	What the number means.
`formula`	expression	yes		Expression over attributes, modifiers, level, and resources.

damageTypes`rules.damageTypes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the damage type.
`name`	string	yes		Display name.
`description`	string		`""`	What this kind of harm is.
`tags`	id[]		`[]`	Labels a damage interaction can except on, such as silvered.

conditions`rules.conditions`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the condition, used as actor.conditions.<id>.
`name`	string	yes		Display name.
`description`	string		`""`	What being in this state means.
`tags`	id[]		`[]`	Free labels for grouping and gating.
`stacking`	`refreshextendstackignore`		`"refresh"`	What a second application does. Refresh, extend, stack, or ignore.
`defaultDuration`	expression			Rounds it lasts when the applying effect names no duration.
`onApply`	effect[]		`[]`	Effects run once, when it lands.
`onTick`	effect[]		`[]`	Effects run at the start of each of the sufferer's turns.
`onExpire`	effect[]		`[]`	Effects run once, when it ends.
`modifiers`	{ id: expression }		`{}`	Derived stat adjustments while it holds. Magnitude is in scope.
`prevents`	id[]		`[]`	Action type ids this forbids. A bare id, not a checked reference.
`suppressesSenses`	id[]			Senses this shuts off, unless the sense itself ignores this condition.
`swings`	object			Which way the dice lean while this is on you. Prefer it or modifiers, not both.
`concealsIdentity`	boolean		`false`	Makes a witness less able to name who did the deed.
`savingThrow`	object			A save to shrug it off, and when that save is offered.
`implies`	id[]		`[]`	Condition ids that come with this one. A bare id, not a checked reference.
`extra`	{ string: any }		`{}`	Open bag of your own data on this condition.

conditions → swings`rules.conditions.swings`

Field	Type	What it does
`ownAttacks`	`advantagedisadvantage`	How attack rolls made by the afflicted creature lean.
`attacksAgainstSelf`	`advantagedisadvantage`	How attack rolls made against the afflicted creature lean.
`checks`	`advantagedisadvantage`	How the afflicted creature's ability checks lean.
`saves`	`advantagedisadvantage`	How the afflicted creature's saving throws lean.

conditions → savingThrow`rules.conditions.savingThrow`

Field	Type	Req	Default	What it does
`save`	rules.savingThrows	yes		Which saving throw resists it.
`difficulty`	expression	yes		Difficulty of that save, as an expression.
`timing`	`onApplyendOfTurnstartOfTurnboth`		`"endOfTurn"`	When the save is offered. On landing, on turn ends, or both.

actionTypes`rules.actionTypes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the action type, such as action or bonus.
`name`	string	yes		Display name.
`description`	string		`""`	What this slice of a turn is for.
`perTurn`	number		`1`	How many a creature gets each turn.

equipmentSlots`rules.equipmentSlots`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the slot, named by an item's slot field.
`name`	string	yes		Display name.
`capacity`	number		`1`	How many items fit here at once.

itemProperties`rules.itemProperties`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the property, named by an item's properties list.
`name`	string	yes		Display name.
`description`	string		`""`	What carrying this property means.
`modifiers`	{ id: expression }		`{}`	Derived stat adjustments an item with this property grants.
`attackStats`	rules.attributes[]			Attributes a weapon with this may also attack with. The best is used, for damage too.
`extra`	{ string: any }		`{}`	Open bag of your own data on this property.

masteryTiers`rules.masteryTiers`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the tier, asked for by a requirement as minTier.
`name`	string	yes		Display name.
`description`	string		`""`	What this level of skill means.
`atRank`	number	yes		Skill rank at which the tier is reached.

rests`rules.rests`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the rest, named by a rest action and by spellcasting recovery.
`name`	string	yes		Display name.
`description`	string		`""`	What this kind of rest is.
`duration`	number		`60`	Minutes of world time it consumes.
`kind`	`shortlong`		`"short"`	Whether resources use their short rest or long rest fraction.
`effects`	effect[]		`[]`	Extra effects run on finishing, beyond resource restoration.
`interruptChance`	number		`0`	Chance per rest that something interrupts it, 0 to 1.

resolution`rules.resolution`

Field	Type	Default	What it does
`checkDice`	dice	`"1d20"`	The notation every check rolls.
`advantageDice`	dice	`"2d20kh1"`	Notation rolled instead when a check has advantage.
`disadvantageDice`	dice	`"2d20kl1"`	Notation rolled instead when a check has disadvantage.
`swingStacking`	`cancelnet`	`"cancel"`	What a roll does with more than one swing: cancel them out, or go by the count.
`criticalSuccessAt`	number	`20`	Natural roll at or above which a check crits. Null for no crits.
`criticalFailureAt`	number	`1`	Natural roll at or below which a check fumbles. Null for no fumbles.
`criticalScope`	`attacksavecheck`[]	`["attack","save","check"]`	Which kinds of roll can crit or fumble: attack, save, check.
`criticalDamageMultiplier`	number	`2`	What a critical hit multiplies damage by.
`saveSuccessMultiplier`	number	`0.5`	Damage kept on a successful save when the ability says half.
`passiveBase`	number	`10`	Number a passive score adds its modifier to instead of rolling.
`opposedMode`	`passivecontested`	`"passive"`	Whether an opposed check rolls both sides or rolls against a passive score.
`damageRounding`	`floorroundceil`	`"round"`	How fractional damage resolves to a whole number.
`reputationRounding`	`floorroundceiltrunc`	`"trunc"`	How fractional reputation change resolves to a whole number.
`attackBonus`	expression		What a weapon attack adds. Omitted, just the attribute modifier, which never grows.
`defaultDifficulty`	number	`12`	Difficulty used when a check names none.
`difficulties`	{ id: number }	`{}`	Named difficulties, so content can ask for hard rather than 18.

progression`rules.progression`

Field	Type	Req	Default	What it does
`maxLevel`	number		`20`	Level the curve stops at. Experience past it is kept but grants nothing.
`levels`	object[]	yes		One entry per level, in order, with its cost and what it gives.
`proficiency`	expression			Formula for the proficiency bonus over actor.level.
`proficiencyRank`	number		`1`	Skill rank a proficiency counts as when a requirement asks.
`levelVitality`	object		`{}`	How the vital resource grows on gaining a level.

progression → levels`rules.progression.levels`

Field	Type	Req	Default	What it does
`level`	number	yes		Which level this entry describes.
`xpRequired`	number	yes		Total experience needed to reach it.
`grants`	effect[]		`[]`	Effects run on each character crossing this level.

progression → levelVitality`rules.progression.levelVitality`

Field	Type	Default	What it does
`policy`	`rollaveragemaxnone`	`"roll"`	Roll the die, take its average, take its maximum, or grant nothing.
`die`	`classsize`	`"class"`	Whether the die comes from the character's class or their size.
`bonus`	expression	`0`	Expression added on top of the die, per level.

savingThrows`rules.savingThrows`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the save, named by abilities and conditions.
`name`	string	yes		Display name.
`description`	string		`""`	What this save resists.
`attribute`	rules.attributes	yes		Attribute whose modifier the save adds.
`defaultDifficulty`	expression			Difficulty used when the thing calling for the save names none.
`extra`	{ string: any }		`{}`	Open bag of your own data on this save.

sizes`rules.sizes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the size.
`name`	string	yes		Display name.
`space`	number		`5`	Distance units the creature occupies. Converted to tiles by the engine.
`reach`	number		`5`	Distance units the creature can reach to strike.
`carryMultiplier`	number		`1`	Not read by the engine. Build encumbrance from actor.carried and a derived stat.
`hitDie`	dice			Vitality die for creatures of this size, when levelVitality takes its die from size.
`extra`	{ string: any }		`{}`	Open bag of your own data on this size.

creatureTypes`rules.creatureTypes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the creature type.
`name`	string	yes		Display name.
`description`	string		`""`	What this kind of creature is.
`tags`	id[]		`[]`	Free labels for grouping and gating.
`extra`	{ string: any }		`{}`	Open bag of your own data on this creature type.

senses`rules.senses`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the sense, used as a key in emits and in a creature's senses.
`name`	string	yes		Display name.
`description`	string		`""`	What this sense picks up.
`defaultRange`	number		`60`	Distance units a creature perceives with it unless it says otherwise.
`ignores`	id[]		`[]`	Not read by the engine yet. No condition currently suppresses a sense.
`propagation`	`linefield`		`"line"`	Whether the signal travels in a straight line or fills the space.
`blockedBy`	`opaqueimpassablenothing`		`"opaque"`	What stops it. Opaque terrain, anything impassable, or nothing.
`falloff`	`clifflinear`		`"cliff"`	Whether strength drops off a cliff at range or fades with distance.
`lingerMinutes`	number		`0`	How long a trace stays after whatever left it has gone. Scent, not sight.
`spreadPerMinute`	number		`0`	How fast it travels, in tiles a minute. Zero arrives at once.
`spreadRetention`	number		`0.5`	Signal left at the far edge of reach once it has spread that far.
`rememberMinutes`	number		`0`	How long a creature holds on to something it noticed with this sense.
`impressionTextKey`	narrative.textGrammar			Text pool for a clear impression.
`faintImpressionTextKey`	narrative.textGrammar			Text pool for a weak impression.
`emptyTextKey`	narrative.textGrammar			Text pool for sensing and finding nothing.
`thresholds`	object		`{}`	Signal strengths at which noticing turns into investigating and then attacking.
`extra`	{ string: any }		`{}`	Open bag of your own data on this sense.

senses → thresholds`rules.senses.thresholds`

Field	Type	Default	What it does
`detect`	number	`0`	Strength at which the creature knows something is there, 0 to 1.
`investigate`	number	`0`	Strength at which it goes to look, 0 to 1.
`aggro`	number	`0`	Strength at which it treats the source as a target, 0 to 1.

stances`rules.stances`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the stance.
`name`	string	yes		Display name.
`description`	string		`""`	What moving this way means.
`speedMultiplier`	number		`1`	What it does to movement speed.
`emits`	{ rules.senses: number }		`{}`	Signal strength this stance gives off, per sense.
`concealedBy`	content.skills			Skill whose rank makes this stance quieter.
`concealmentPerPoint`	number		`0`	Signal removed per rank of that skill.
`extra`	{ string: any }		`{}`	Open bag of your own data on this stance.

movementModes`rules.movementModes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the mode, such as walk, swim, or fly.
`name`	string	yes		Display name.
`defaultSpeed`	number		`30`	Distance units per turn for a creature that names no speed of its own.
`terrainMultiplier`	number		`1`	What this mode does to terrain movement costs.
`fallsWhenDisabled`	boolean		`false`	Not read by the engine yet. Nothing takes a movement mode away.
`extra`	{ string: any }		`{}`	Open bag of your own data on this mode.

languages`rules.languages`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the language.
`name`	string	yes		Display name.
`description`	string		`""`	Who speaks it and where.
`script`	string		`""`	Not read by the engine. The writing system, for flavour.
`exotic`	boolean		`false`	Not read by the engine. Dialogue and readable content are not language gated.
`extra`	{ string: any }		`{}`	Open bag of your own data on this language.

alignments`rules.alignments`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the alignment.
`name`	string	yes		Display name.
`abbrev`	string		`""`	Short form for tight displays.
`extra`	{ string: any }		`{}`	Open bag of your own data on this alignment.

opportunities`rules.opportunities`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the opportunity.
`name`	string	yes		Display name.
`description`	string		`""`	What this reaction is and why everyone has it.
`on`	`moveAwaycastSpellrangedAttackstandUpbeHitallyHitcustom`		`"moveAway"`	What provokes it. Leaving reach, casting, shooting, standing, being hit, or custom.
`event`	string			Event name to watch, when on is custom.
`actionType`	rules.actionTypes			Action type it spends. Without one it is free.
`use`	content.abilities			Ability the reacting creature uses. Without one, only effects run.
`requires`	predicate			Predicate that must hold for it to trigger. Not the requirement object.
`effects`	effect[]		`[]`	Effects run when it triggers.
`usesPerRound`	number		`1`	How many times one creature may take it each round.
`extra`	{ string: any }		`{}`	Open bag of your own data on this opportunity.

coverTypes`rules.coverTypes`

Field	Type	Req	Default	What it does
`id`	id	yes		Id of the cover type.
`name`	string	yes		Display name.
`defenceBonus`	number		`0`	Added to the defended stat when the target has this cover.
`blocksTargeting`	boolean		`false`	True when the target cannot be picked at all, not merely harder to hit.
`extra`	{ string: any }		`{}`	Open bag of your own data on this cover type.

spellcasting`rules.spellcasting`

Field	Type	Default	What it does
`mode`	`noneslotspointsboth`	`"none"`	Whether casting spends slots, spends points, both, or is off.
`maxSpellLevel`	number	`9`	Highest spell level the game has.
`slotTable`	{ string: number[] }	`{}`	Slots per spell level, keyed by caster level.
`pointResource`	rules.resources		Resource points are drawn from, when the mode uses points.
`pointCosts`	{ string: number }	`{}`	Point cost per spell level.
`saveDifficulty`	expression		Formula for the difficulty of a save against a caster's spell.
`attackBonus`	expression		Formula for a spell attack bonus, overriding the ordinary attack stat.
`concentration`	object	`{}`	Whether holding a spell can be broken, and by what.
`recoverOn`	rules.rests[]	`[]`	Which rests give slots back.
`ritualCasting`	boolean	`false`	Whether spells marked ritual can be cast without spending a slot.
`componentActionTypes`	object	`{}`	Action types verbal and somatic components need free.
`extra`	{ string: any }	`{}`	Open bag of your own data on spellcasting.

spellcasting → concentration`rules.spellcasting.concentration`

Field	Type	Default	What it does
`enabled`	boolean	`true`	Whether concentration exists at all.
`savingThrow`	rules.savingThrows		Save rolled to keep concentration on taking damage.
`difficulty`	expression		Difficulty of that save, as an expression.
`maxConcurrent`	number	`1`	How many concentration spells one caster may hold.

spellcasting → componentActionTypes`rules.spellcasting.componentActionTypes`

Field	Type	Req	Default	What it does
`verbal`	rules.actionTypes			Action type a verbal component occupies.
`somatic`	rules.actionTypes			Action type a somatic component occupies.

perception`rules.perception`

Field	Type	Default	What it does
`sightSense`	rules.senses		Which sense counts as sight, and so decides what the map shows as explored.
`curiosityMinutes`	number	`10`	How long a creature keeps walking toward something it noticed.
`defaultStance`	rules.stances		Stance a creature is in when it names none.
`minimumEmission`	number	`0.01`	Signal below this is treated as nothing, 0 to 1.
`maxMarksPerTile`	number	`4`	How many traces one tile keeps per sense. The oldest fall off.
`extra`	{ string: any }	`{}`	Open bag of your own data on perception.

temperament`rules.temperament`

Field	Type	Default	What it does
`roamRadius`	number	`0`	How far from where it was placed it will wander. Zero stands still.
`investigateRadius`	number		How far from that spot a lead may pull it. Absent is no limit.
`leashRadius`	number		How far it chases before turning for home. Absent is no limit.
`wanderChance`	number	`0`	Odds it moves at all on a given idle step, 0 to 1.
`disengageTurns`	number	`0`	Rounds it stays in a fight after nobody can perceive anybody.
`speeds`	object	`{}`	How fast it moves for each reason it moves, as multipliers.
`investigates`	rules.senses[]		Senses it acts on, best first. Absent means all of them.
`followsTrails`	boolean	`true`	Whether a trace on the ground is worth following at all.
`notices`	`hostileneutralally`[]	`["hostile"]`	Whose presence it registers: hostile, neutral, ally.
`extra`	{ string: any }	`{}`	Open bag of your own data on temperament.

temperament → speeds`rules.temperament.speeds`

Field	Type	Default	What it does
`wander`	number	`1`	Pace while wandering its own ground. Zero never wanders.
`investigate`	number	`1`	Pace while walking toward something it noticed.
`engage`	number	`1`	Pace while closing on something it means to fight.
`returning`	number	`1`	Pace while heading back to where it was placed.

currency`rules.currency`

Field	Type	Default	What it does
`name`	string	`"coins"`	What money is called in the plural.
`abbrev`	string	`"c"`	Short form for tight displays.
`allowNegative`	boolean	`false`	Whether the purse may go into debt.

interactionRange`rules.interactionRange`

Field	Type	Req	Default	What it does
`talk`	number		`2`	How many tiles away you can start a conversation.
`reach`	number		`1`	How many tiles away you can take, open, or otherwise handle a thing.

search`rules.search`

Field	Type	Req	Default	What it does
`trapRadius`	number		`2`	How many tiles a search sweeps for traps.
`disarmReach`	number		`1`	How many tiles away a trap can be disarmed from.

dispositionBands`rules.dispositionBands`

Field	Type	Req	What it does
`id`	id	yes	Id of the band.
`atLeast`	number		Lowest disposition in this band. The highest matching band wins.
`stance`	`allyneutralhostile`	yes	How a creature in this band treats the party.

rulesrules

attributesrules.attributes

resourcesrules.resources

derivedStatsrules.derivedStats

damageTypesrules.damageTypes

conditionsrules.conditions

conditions → swingsrules.conditions.swings

conditions → savingThrowrules.conditions.savingThrow

actionTypesrules.actionTypes

equipmentSlotsrules.equipmentSlots

itemPropertiesrules.itemProperties

masteryTiersrules.masteryTiers

restsrules.rests

resolutionrules.resolution

progressionrules.progression

progression → levelsrules.progression.levels

progression → levelVitalityrules.progression.levelVitality

savingThrowsrules.savingThrows

sizesrules.sizes

creatureTypesrules.creatureTypes

sensesrules.senses

senses → thresholdsrules.senses.thresholds

stancesrules.stances

movementModesrules.movementModes

languagesrules.languages

alignmentsrules.alignments

opportunitiesrules.opportunities

coverTypesrules.coverTypes

spellcastingrules.spellcasting

spellcasting → concentrationrules.spellcasting.concentration

spellcasting → componentActionTypesrules.spellcasting.componentActionTypes

perceptionrules.perception

temperamentrules.temperament

temperament → speedsrules.temperament.speeds

currencyrules.currency

interactionRangerules.interactionRange

searchrules.search

dispositionBandsrules.dispositionBands