dschonholtz/.claude/skills/spell-template

Skill: Add a New Spell

The SPELL_DEFS registry in index.html is the single source of truth for all spells.

Step 1: Add to SPELL_DEFS

const SPELL_DEFS = {
  fireball:    { color: 0xff6600, size: 0.8, speed: 22,  maxLifeMs: 1333, cooldownMs:  666, icon: '🔥', label: 'Fireball',    key: '1' },
  frostbolt:   { color: 0x44aaff, size: 0.6, speed: 14,  maxLifeMs: 2000, cooldownMs: 1000, icon: '❄️',  label: 'Frostbolt',   key: '2' },
  telekinesis: { color: 0xaa44ff, size: 1.0, speed: 18,  maxLifeMs: 1667, cooldownMs: 1500, icon: '🔮', label: 'Telekinesis', key: '3' },

  // New spell:
  lightning:   { color: 0xffff44, size: 0.4, speed: 40,  maxLifeMs:  600, cooldownMs:  400, icon: '⚡', label: 'Lightning',   key: '4' },
};

Field reference

| Field | Type | Description | |---|---|---| | color | hex int | Projectile color | | size | float | Sphere radius | | speed | float | Units/second | | maxLifeMs | int | Ms before expiry | | cooldownMs | int | Ms between casts | | icon | string | Emoji for HUD | | label | string | Display name | | key | string | Keyboard key ('1'–'9') |

Step 2: Add to server allowlist

In server/lib/MessageHandler.js:

_onSpellCast(ws, msg) {
  const ALLOWED = ['fireball', 'frostbolt', 'telekinesis', 'lightning']; // add here
  if (!ALLOWED.includes(msg.type)) return;
  // ...
}

Step 3: Test

1. Start server + open game (see test-multiplayer/SKILL.md)
2. Press the key from SPELL_DEFS.key
3. Verify: correct color, speed, cooldown, visible in second browser tab

Advanced: custom behavior

Add a behavior field and handle it in MmdSpell.update(dt):

// SPELL_DEFS entry:
homing: { ..., behavior: 'homing' }

// MmdSpell.update(dt):
update(dt) {
  if (this.def.behavior === 'homing' && this.target) {
    const dir = this.target.position.clone().sub(this.mesh.position).normalize();
    this.direction.lerp(dir, dt * 3);
  }
  this.mesh.position.addScaledVector(this.direction, this.def.speed * dt);
  this.lifeMs += dt * 1000;
  return this.lifeMs > this.def.maxLifeMs;
}

Particle effects (future pattern)

Attach sub-mesh to this.mesh in MmdSpell constructor, update in update(dt), dispose via scene.remove + .dispose() on expiry. Keep effect geometry cheap — under 50 tris per spell in flight.