Curated spells and the full SRD

Explanation. To add a spell of your own, follow the steps in the GM guide.

The built-in spell list in src/data/spells/ is a curated selection, and most of it comes from the System Reference Document (SRD) 5.1. The SRD 5.1 lists 319 spells, and the app ships 111. Three built-in spells come from outside the SRD: Witch Bolt, Ray of Sickness, and Destructive Wave appear only in the Player’s Handbook. Each shipped spell has rules that the spell resolver applies in full, or a description that names the clause that the resolver leaves to the GM.

The built-in list

The list covers each spell level from cantrip to 9th level. It includes spells for all six full caster classes: bard, cleric, druid, sorcerer, warlock, and wizard. It also uses all six effect kinds that the resolver handles: attack, save, heal, buff, summons, and utility.

The paladin and the ranger share leveled spells with the other classes. The paladin also has Divine Favor and Destructive Wave, which comes from the Player’s Handbook. The ranger has Hunter’s Mark.

The selection prefers spells whose rules the current mechanics resolve in full. The resolver applies these rules:

• A d20 spell attack against AC. A melee spell attack gets the melee side of Prone and of an automatic critical hit, and some attacks deal half their damage on a miss.
• A condition that a spell attack’s hit imposes, with or without a save against it, and a hit that gives the caster back part of the damage it deals.
• Several projectiles from one cast, each rolled on its own and split between the creatures that the caster picks.
• A save against the spell save DC of the caster, with damage that the save halves or negates.
• A rule that reads the current hit points of the target in place of a save. An HP pool reaches the creatures with the lowest HP first, and an HP limit fails the save with no roll. A failed save can kill outright.
• Dice of healing, or a flat amount of healing.
• A heal that stabilizes a dying character, as Spare the Dying does.
• A condition chip that adds a die or a flat amount to the later attack rolls, saving throws, or ability checks of the target.
• A condition chip for one of the eleven standard conditions that have rules. Such a chip gives advantage or disadvantage on later d20 rolls, makes a melee hit a critical hit, fails a save with no roll, or costs the holder its turn.
• A condition chip that a failed save imposes, with a new save at the end of each turn of the target.
• A group of summoned creatures from one library template, which stay while the caster maintains concentration.
• Damage that a hit or a failed save leaves on the target, rolled at the end of each of the target’s turns. With a repeated save, the damage lands only when that save fails.
• A condition chip that ends at a turn boundary: the start or the end of the caster’s next turn, or the end of the target’s next turn.
• A chip that gives advantage or disadvantage on the attack rolls of its holder, or on attack rolls against its holder. A one-shot chip ends after the first attack roll it applies to, as Guiding Bolt and Vicious Mockery do.
• A spell that the caster uses again on each later turn while it lasts, with no new slot.
• A condition chip that ends when its holder takes damage.
• A condition chip that changes the AC of its holder: a flat bonus, a base AC for a holder without body armor, or a floor under the AC.
• A condition chip that raises the HP maximum of its holder, grants temporary hit points at the cast or at the start of each of its turns, or makes it immune to a condition.
• A condition chip that gives its holder resistance to damage types, with one type that the caster picks at the cast.
• A condition chip that gives its holder advantage on the saves of one ability, or an extra action on each of its turns for one weapon attack.
• Damage or effect scaling by spell slot level, and by caster level for cantrips. A spell can also scale once per two slot levels.

A condition chip is the label on a creature or a character that records a condition, such as Blinded or Bless.

One-roll and lasting riders

A rider is the die or the flat amount that a chip adds to later rolls. Guidance and Resistance have a one-roll rider, as in the printed rules. The first matching roll uses the die, and the app then removes the chip. Guidance adds 1d4 to one ability check, and Resistance adds 1d4 to one saving throw.

Bless and Bane have a lasting rider. The chip adds or subtracts 1d4 on each attack roll and saving throw until its duration ends or the caster stops concentrating.

Later turns

Acid Arrow, Phantasmal Killer, and Weird leave a chip on the target. The chip deals its damage at the end of the turns of that creature, and it ends at the boundary that the spell names. Phantasmal Killer and Weird deal their damage only when the repeated save fails, and a success ends the spell. Each caster’s cast has its own chip, so two Acid Arrows on one ogre both deal their later damage, and a target that is already Frightened still takes the chip of Phantasmal Killer.

Witch Bolt, Spiritual Weapon, Call Lightning, Sunbeam, and Arcane Sword leave a chip on the caster, named after the spell. While the caster has that chip, a cast of the same spell is a repeat. The dialog says Repeat, offers no slot, and costs the action or bonus action that the spell names. A repeat of Witch Bolt deals 1d12 to the creature that the first cast hit, with no roll. If the caster can also cast the spell anew, the app first asks whether to repeat it or cast it anew with a slot. A new cast can pick a new target and a higher slot, and it replaces the chip of the old repeat.

A chip that ends at a turn boundary shows “next turn” in place of a round count. Outside a fight there are no turns, so such a chip lasts one round. The app deals later-turn damage only at the end of a turn in a fight, so an Acid Arrow cast outside a fight deals no later damage, and the GM applies it by hand. The end of a fight removes every chip that ends at a turn boundary, and it first deals the later-turn damage that such a chip still owes. A dying character takes that damage at the end of its turn, and each hit costs it a failed death save.

Two effects in one hit

Ray of Sickness rolls its attack first. A creature that it hits then makes a CON save against the spell save DC of the caster, and on a failure it is Poisoned until the end of the caster’s next turn. The creature saves once, even when several projectiles of one spell hit it.

Vampiric Touch gives the caster hit points equal to half the necrotic damage that its hit deals. The app counts the damage after the resistances of the target, so a hit on a creature that resists necrotic damage gives back less. Vampiric Touch also repeats on each later turn, as Spiritual Weapon does.

Chill Touch leaves a chip on the creature that it hits, and the creature regains no hit points until the start of the next turn of the caster. A heal from a spell or from the GM has no effect and the log says why, but temporary hit points still land. An undead target also takes a second chip, so it attacks the caster at disadvantage until the end of the next turn of the caster. Its weapon attacks and spell attacks against other creatures roll as usual.

Creature types

A spell can name creature types in effect.typeRules. Sleep and Hold Monster have no effect on undead, Hold Person and Charm Person affect only humanoids, and the healing spells have no effect on undead or constructs. Blight has no effect on undead or constructs, and a plant saves at disadvantage and takes the maximum damage. Sunburst and Sunbeam give undead and oozes disadvantage on the save. Sleep and Hypnotic Pattern pass over a creature immune to Charmed. A party character counts as humanoid. A creature with no type matches no rule, and it still counts for an only list, so the GM decides whether the spell reaches it.

Hit-point rules

Sleep and Color Spray roll a pool of hit points and roll no save. The app sorts the chosen targets by current HP, lowest first. Each target whose HP fits in what the pool has left takes the condition, and its HP comes out of the pool. The pool passes over a target at 0 HP, an Unconscious target, and a target that already has the condition of the spell. The log states the pool roll, and for each target whether the pool reached it. These lines are GM-only, because the pool total and the order of the walk bound the HP of each foe. A Player tab reads the dice of the pool and whether each target is affected, with no reason (see GM-only lines).

Sleep ends on a creature when that creature takes damage, including damage that its temporary hit points absorb. The pool passes over an undead target and a target immune to Charmed, and such a target spends none of the pool. The app reads the creature type and the condition immunities of each creature, and an untyped creature counts as neither. A creature that an ally shakes awake loses its chip when the GM removes it.

Hypnotic Pattern rolls a WIS save for each creature in its area, and a failure leaves an Incapacitated chip that ends when its holder takes damage, as the chip of Sleep does. The Charmed condition of the spell has no rules of its own in the app, so the chip names only the incapacitation.

Power Word Kill reads the current HP of the target. A target with 100 HP or fewer dies with no roll, and one with more is unaffected. A creature dies at 0 HP. A character dies through the death-save tracker, the same way as a death from exhaustion, and keeps the HP that the GM tracks.

Armor class

Shield of Faith gives its target +2 AC while the caster concentrates. Shield gives its caster +5 AC until the start of the caster’s next turn. Its range is Self, so the cast dialog offers only the caster as the target. When an attack roll hits a caster who has Shield ready, and the AC that Shield really adds would turn the hit into a miss, the app pauses before the damage and asks whether the caster casts it. A yes spends the reaction and the slot, and the app checks the roll again against the new AC. A weapon swing and an attack spell both pause, and Shield blocks every dart of Magic Missile, also when the target already has Shield. The question goes only to a tab that may act for the caster, so an attack that a player tab rolls against a foe does not pause. The GM then casts the foe’s Shield from the reaction control of the combat screen, and undoes the damage by hand.

Mage Armor gives a character with no body armor a base AC of 13 plus its DEX modifier, and a shield still adds to it. A higher base on the character sheet, or a higher unarmored defense, wins. On a creature with no armor, the spell raises a lower AC to 13 plus the DEX modifier. A creature has no shield field, and its authored AC already includes any shield it carries, so the spell drops the +2 of a shield that is part of that AC. A creature with AC 12 from DEX 10 and a shield gets AC 13 and not 15, and the GM applies the difference by hand. The chip stays when the holder puts armor on, but it then changes nothing, and the GM removes it.

Barkskin sets a floor of 16 under the AC of its target. The floor applies after every bonus, so Shield of Faith on a target with AC 12 gives AC 16, not 18.

The character sheet, the combatant cards, and every attack roll read the same AC, so each of them shows the change while the chip lasts.

Hit points and immunity

Aid raises the HP maximum and the current HP of up to three creatures by 5, and by 5 more for each slot level above 2nd. The raise goes into the stored maximum, so the character sheet, the combatant cards, and every heal read it with no extra step. When the chip ends, the maximum drops back, and current HP drops only where it sits above the new maximum. A GM who types a new maximum while Aid lasts types the raised value, and the end of the spell still takes the 5 off. Aid on a character at 0 HP brings the character back up with 5 HP.

Divine Favor and Hunter’s Mark add damage dice to weapon hits. Divine Favor adds 1d4 radiant to each weapon hit of its caster. Hunter’s Mark puts a chip on a foe, and each weapon hit of the caster against it adds 1d6 of the weapon’s damage type. A critical hit doubles both. When the marked foe drops to 0 HP, the Repeat (no slot) cast moves the mark for a bonus action. The GM checks that the old target dropped, and rules the advantage on Wisdom checks to find the target. The longer duration of Hunter’s Mark from a 3rd-level or higher slot is text only, because the app has no duration scaling.

False Life gives its caster 1d4 + 4 temporary hit points, and 5 more for each slot level above 1st. Heroism gives its target temporary hit points equal to the spellcasting modifier of the caster at the start of each of its turns. Temporary hit points never add up. A new grant replaces the old amount only when it is larger, and the log says when it is not. The temporary hit points of both spells end with the chip, and temporary hit points that the GM types stay until damage uses them. A creature has temporary hit points too, and damage takes them first.

Heroism also makes its target immune to Frightened. The cast ends a Frightened chip that the target has, and a later spell that imposes Frightened does not land. The log names the chip that blocks it. A chip that the GM adds by hand still lands.

Damage resistance

Stoneskin gives its target resistance to bludgeoning, piercing, and slashing damage from a nonmagical weapon. A weapon counts as magical when its item has the Magical weapon box ticked, and damage from a spell always gets through.

Protection from Energy asks the caster for one damage type in the cast dialog: acid, cold, fire, lightning, or thunder. The chip resists the picked type until the spell ends. A spell of your own can offer the same pick. Write a resistChoice list of damage types on its buff effect, and the cast dialog offers those types.

Absorb Elements is not in the SRD, so the app does not ship it. To author it, add a 1st-level spell with a reaction casting time and a buff effect. Set Caster picks one of to acid, cold, fire, lightning, thunder, and set the chip to end at the start of the caster’s next turn. A weapon hit, a spell attack hit, or a save spell that deals one of those types then offers the reaction after its damage roll. The extra 1d6 on the caster’s next melee hit has no field, so add it by hand.

Speed of action

Haste gives its target +2 AC, advantage on DEX saves, and an extra action on each of its turns. The combat card counts one more weapon swing while the chip lasts. The extra swing comes after the Attack action and the swings that Extra Attack adds, or after an action spent on a cast. Nothing banks behind it, so a fighter with Extra Attack gets three swings in a turn. The extra action can’t pay for a cast. Dash, Disengage, Hide, and Use an Object have no rule in the app, so the GM runs them. The doubled speed has no rule either, because nothing moves a token by feet.

The advantage reads at every save that the app rolls: a spell’s save, a save that a chip retries at the end of a turn, a concentration save, and a save from the character sheet. Restrained gives disadvantage on the same save, so a restrained target under Haste rolls one die.

When Haste ends, the target gets a Lethargic chip, and the log notes that it can’t move or take actions until after its next turn. The chip ends at the end of the next turn of the target, so it waits for two turn ends when Haste ends during that turn. The turn pointer steps past a lethargic combatant, and the chip does not break concentration. Every path that ends a chip adds it: a turn boundary, a round tick, the end of the concentration of the caster, a Haste from another caster that replaces the first, and a chip that the GM removes by hand. Outside a fight the chip lasts one round.

Spells described in prose

Twenty-five built-in spells have the utility effect kind. Their rules exist only as text in the description of each spell, and the GM applies them. Light, Counterspell, and eight cantrips are in the list because a GM notices when a spell this common is missing. The cantrips sit in src/data/spells/cantrips.js: Mage Hand, Prestidigitation, Thaumaturgy, Druidcraft, Mending, Message, Minor Illusion, and Dancing Lights.

The other fifteen are in src/data/spells/utility.js: Detect Magic, Disguise Self, Jump, Silent Image, Speak with Animals, Alter Self, Levitate, Bestow Curse, Slow, Speak with Dead, Arcane Eye, Compulsion, Confusion, Polymorph, and Conjure Elemental. The eldritch invocations of a warlock cast most of them.

Partial rules

Some entries have one clause that the app cannot resolve beside a payload that it can. The description of each entry states the difference:

• Blindness/Deafness always blinds, because deafness has no rule in the app.
• Flame Strike raises its fire dice at a higher slot. The printed spell lets the caster choose the fire dice or the radiant dice.
• Destructive Wave always deals radiant damage beside its thunder. The Player’s Handbook lets the caster pick radiant or necrotic.
• Conjure Animals always summons wolves: eight, doubled with a 5th-level slot, tripled with a 7th-level slot, and quadrupled with a 9th-level slot.
• Witch Bolt ends when the caster uses its action for something else, or when the target moves out of range. The GM ends it by hand.
• Spiritual Weapon and Arcane Sword move up to 20 feet before each attack. The GM tracks where each one is.
• Shatter gives disadvantage on the save to a creature of stone, crystal, or metal. No creature type marks such a creature, so the GM rolls that save by hand when the cast also catches other creatures.
• Fear lets a frightened creature retry the save only when it ends its turn out of line of sight of the caster. The app has no line of sight, so the chip has no automatic retry and the GM rolls it.
• Call Lightning deals 1d10 more when the caster takes control of a storm outdoors, and Produce Flame sheds light. The GM rules both.
• Ray of Frost, Shocking Grasp, and Thunderwave deal their damage. The GM applies the rest: the lost speed, the lost reactions, and the push.
• Protection from Evil and Good gives disadvantage only to an attacker whose creature type is on its list. The GM rules the charm, fright, and possession clause. Blur does not check for blindsight or truesight, and Faerie Fire does not cancel invisibility, so the GM rules both.
• Disintegrate turns a target at 0 HP to dust, and Finger of Death raises a slain humanoid as a zombie. The GM rules both.
• Revivify and Raise Dead raise only a dead target, and Raise Dead passes over undead. The GM checks that the target died within the last minute for Revivify, or within 10 days for Raise Dead. The GM also rules the -4 penalty that Raise Dead leaves, and the poisons and diseases it ends.
• Lesser Restoration ends a Blinded, Deafened, Paralyzed, or Poisoned chip, and the caster picks one when the target has more than one. Heal ends the Blinded and Deafened chips beside its 70 HP. The app tracks no diseases, so the GM ends a disease.
• Greater Restoration ends one level of exhaustion, or a Charmed, Petrified, or Bestow Curse chip. The GM rules a curse without a chip, an ability score reduction, and an HP maximum reduction.
• A restoration that ends a chip from a concentration spell leaves the caster concentrating.

Spells that need a missing mechanic

Each omitted spell needs a mechanic that the app does not have. If the list included such a spell, it would print rules that the app cannot apply.

Movement and turn control

Examples: Banishment, Command, and Dominate Person. Slow and Confusion ship as prose entries (see Spells described in prose), and their rules need the mechanics below.

A failed save can add a condition chip, and this part works. Hold Person, Hold Monster, Blindness/Deafness, Fear, and Sunburst all ship. The other clauses of these spells need more:

• Slow halves the speed of the target, but no rule moves a token by feet, so speed has no effect in a fight.
• Slow also takes away an action. The combat screen tracks the action, the bonus action, and the reaction of each turn. A chip can add an action, as Haste does, but no chip takes one away.
• Banishment removes the creature from the map.
• Dominate Person gives control of one creature to another.

Lingering zones

Examples: Web, Grease, Wall of Fire, Cloudkill, Moonbeam, and Spirit Guardians.

Area targeting lets the caster pick the creatures that the spell hits. A spell with targetCount: 0 offers every reachable combatant, and the caster selects each creature in the area. Fireball, Shatter, Circle of Death, and Fire Storm work this way.

A cast resolves once, and the app has no template for map areas. So no rule maintains a zone on the map after the cast.

Buffs outside d20 rolls

Examples: Enlarge/Reduce.

A rider on a d20 roll works. A chip can add or subtract dice and a flat amount on attack rolls, saving throws, and ability checks, as Bless, Bane, Guidance, and Resistance do. A chip can also change AC, as Shield and Barkskin do, and hit points, as Aid, False Life, and Heroism do. A chip can give an extra action, as Haste does, and slant attack rolls, as Faerie Fire and Blur do. The size of a creature has no rule, so a chip can’t change it.

Summon choice and control

Examples: Find Familiar and Animate Dead.

Summoning works. A summons effect names one library creature template and a count. The cast puts those creatures on the tile of the party, and they leave when the caster stops concentrating on the spell.

The app does not have these parts:

• A menu of templates for the caster to choose from.
• A summon that a player runs as a companion. A summon takes its own turn as a combatant.
• A summon that doesn’t require concentration, such as an animated skeleton or a familiar. Such a summon stays until the GM removes it by hand.

Exploration and social spells

Examples: Identify, Suggestion, Divination, and teleportation.

These spells have rules that exist only as text, so they work as utility entries. The built-in list leaves them out only to stay small. A GM can add spells of this group by hand with the least work of any group.

Eldritch invocations

The app models the SRD eldritch invocations of the warlock. The ones that change Eldritch Blast, cast a spell, or grant skills have rules in the app, and the rest, such as Devil’s Sight, are text for the GM. The GM reference lists each effect and the rules that the GM enforces. The app models the Book of Shadows of the Pact of the Tome, with its cantrips from any class and the rituals of Book of Ancient Secrets, and the Mystic Arcanum. It does not model the pact weapon or the familiar of a boon. Pact magic is modeled, so a warlock casts from its own pact pool and not from the standard slot table.

Adding a spell by hand

A built-in spell and a GM-authored spell use the same schema, so a missing spell needs no code change. The Spells rail in Library mode creates a spell. A custom spell whose name matches a default replaces that default.

A library export, campaign-library.json, is portable. A shared file of extra spells merges into the library of any browser.

The attack, save, heal, buff, summons, and utility effects, with scaling by slot level and by cantrip level, cover most mechanics in the SRD. A spell outside them works as a utility entry with its rules in the description. The GM applies those rules by hand, as at a physical table. The GM guide gives the steps.

A new mechanic, such as movement or a lasting zone, lets the list grow. Add the spells that need the mechanic to the level file under src/data/spells/ in the same change.