Manual · Content and homebrew

The `_sheetling` block

Where it goes, its seven keys, one worked entry, the rules about ids and pools, and the same block inside a Fight Club 5 file.

A _sheetling object beside an entry's own text, a sibling of entries. 5eTools ignores keys it does not know, so the file stays valid there.

Where it goes

On a class feature, subclass feature, optional feature, feat, background, item or condition.
On a named block inside a species' entries (a trait), never on the race entry itself.
On the class, subclass, race or subrace entry itself only featureChoices lands, plus spellcasting for a caster class or subclass. Any other key there is reported and dropped; the entry still imports.

The keys

Key	Lands on	What you see on the sheet
`effects`	any entry the block may sit on	a tracker, a toggle, a bonus labelled on the number it changes, a rider offered on an attack, a button that rolls or heals
`replaceEffects`	the same	`true` swaps the format's own effects for yours instead of adding to them
`onUse`	items only	a button on the item's row: `heal` rolls once, `effects` starts a running effect the player dismisses by hand
`prerequisite`	feats and optional features	a real gate: `minLevel`, `abilityAtLeast`, `spellcasting`, `feature`, `spell`, `knownCantrip`
`featureChoices`	the `class`, `subclass`, `race` or `subrace` entry	a pick in the wizard, or on level-up at the level the group names
`spellcasting`	a caster `class` or `subclass`	`spellListOf`: whose spell list a third caster borrows
`text`	any entry except a background and the four entry-level ones	replaces the card's rendered sentence

One entry, four effects

{
  "name": "Ashwing Surge",
  "entries": ["Once between Long Rests, you gain a Fly Speed equal to your Speed while you hold the stance. If the surge would reduce you to 0 Hit Points, you drop to 1 instead. Either spends the charge."],
  "_sheetling": {
    "effects": [
      { "kind": "grants_resource", "id": "show_ashwing_charge", "name": "Ashwing Charge", "max": 1,
        "reset": [{ "on": "long_rest", "amount": "all" }], "display": "counter" },
      { "kind": "grants_toggle", "id": "show_ashwing_on", "name": "Ashwing Surge", "costTrackerId": "show_ashwing_charge" },
      { "kind": "grants_movement", "mode": "fly", "distance": { "equalToWalk": true },
        "condition": { "toggleActive": "show_ashwing_on" } },
      { "kind": "hp_trigger", "id": "show_ashwing_trigger", "name": "Ashwing Surge", "on": "reduced_to_zero",
        "then": { "kind": "stay_at", "hp": 1 }, "uses": { "trackerId": "show_ashwing_charge" } }
    ]
  }
}

A pool, a toggle that spends it, a fly speed gated on the toggle, and a trigger that spends the same pool. Effect kinds lists every kind with its fields.

A pick group

{
  "_sheetling": {
    "featureChoices": [
      { "id": "show_emberkin_ancestry", "level": 1, "name": "Ancestral Line", "count": 1,
        "options": ["Ashborn Line", "Frostborn Line", "Stormborn Line"] }
    ]
  }
}

Each option resolves in order: a same-file class or subclass feature by name, a same-file optional feature, one of this species' own traits, then a shipped id written verbatim (fighter_style_defense). One unresolved option drops the whole group with a row; the entry still imports.

Validation rules

Prefix your ids (show_ above). The block does no namespacing. Two files minting the same tracker id merge into one pool without a word.
Every spend must name a declared pool. A costTrackerId, uses.trackerId or cost.trackerId that names no grants_resource in the same ruleset drops the whole entry, card and all. Nothing ships free and unlimited.
"condition": { "toggleActive": "<id>" } gates an effect on a toggle. A toggle the engine cannot find drops the entry. toggleInactive is the mirror.
A toggle is a stance, and every rest switches it off. A state the story sets, a curse's stage say, needs "persists": true, or the next rest drops everything gated on it.
Two entries carrying the same named effect (a cursed item and the condition it inflicts) get the same stackKey on their modifies, and only the more potent applies.
@self in an item's weapons matcher is that item's own minted id. @counter:<Name> inside a Fight Club <sheetling> element is the tracker of the <counter> of that name.
A wrong key is a row, and only that field is dropped. A dangling id inside an effect that landed refuses the entry. Two entries with one id fail the import.
The format's own prerequisite array gates a pick on level and ability only; the rest stays a sentence. The block's prerequisite is a real gate for all of it.

Inside a Fight Club 5 file

The same JSON, as CDATA in a <sheetling> element, last child of the <feature>, <trait>, <feat> or <item>. Let the format say what it can: a flat bonus is a <modifier>, and a pool the file already has is spent with @counter:.

<autolevel level="1">
  <feature>
    <name>Ashwing Surge</name>
    <text>Your wings flare with banked fire. …</text>
    <sheetling><![CDATA[{
      "effects": [
        { "kind": "grants_toggle", "id": "show_ashwing_on", "name": "Ashwing Surge",
          "costTrackerId": "@counter:Ashwing Surge" }
      ]
    }]]></sheetling>
  </feature>
  <counter><name>Ashwing Surge</name><value>1</value><reset>L</reset></counter>
</autolevel>

A counter's formula may use %N tokens: %1 to %6 are the ability modifiers, Strength to Charisma, and %0 the class's own casting modifier.

Download the showcase file: a species, a subclass, two feats, a background, a spell and an item, every key used once, run by the test suite on every release.