Writing formulas

A curve that gives nothing below 8, then a point every three above it, capped at +6.

{ "clamp": [
    { "floor": { "div": [ { "sub": [ { "ref": "value" }, 8 ] }, 3 ] } },
    0,
    6
] }

A carrying capacity from Might, and a condition that lands when you exceed it. The engine ships no encumbrance rule. This is the whole of one.

{ "when": { "gt": [ { "ref": "actor.carried" }, { "ref": "actor.derived.capacity" } ] },
  "then": [ { "applyCondition": { "target": { "ref": "actor.id" },
                                  "condition": "burdened",
                                  "duration": 1 } } ] }

capacity is a derived stat: { "mul": [ { "ref": "actor.attr.might" }, 15 ] }. A rule like this runs every turn as a passive, from an ancestry trait or an item proc.

Damage rising with caster level, a burn that only lands on a failed save, and a bigger burst at night.

[ { "let": { "name": "blast",
           "value": { "add": [ { "roll": "4d6" },
                               { "mul": [ { "floor": { "div": [ { "ref": "actor.level" }, 4 ] } }, 3 ] },
                               { "cond": { "in": [ { "ref": "world.phase" },
                                                    { "list": [ "dusk", "night" ] } ] },
                                 "then": 4, "else": 0 } ] },
           "in": [ { "damage": { "target": { "ref": "target.id" },
                                 "amount": { "ref": "blast" },
                                 "damageType": "fire" } },
                   { "if": { "when": { "not": { "exists": "target.conditions.warded" } },
                             "then": [ { "applyCondition": { "target": { "ref": "target.id" },
                                                             "condition": "burning",
                                                             "duration": 3 } } ] } } ] } } ]

Put this on an ability with a savingThrow whose onSuccess is half, and the engine halves the damage for you.

Below a third health it heals itself, calls for help, and turns hostile to a faction that abandoned it.

[ { "if": { "when": { "lte": [ { "ref": "actor.res.hp" },
                          { "div": [ { "ref": "actor.max.hp" }, 3 ] } ] },
          "then": [ { "heal": { "target": { "ref": "actor.id" },
                                "amount": { "roll": "4d8" } } },
                    { "applyCondition": { "target": { "ref": "actor.id" },
                                          "condition": "enraged", "duration": 5 } },
                    { "emit": { "event": "warden_called_for_help",
                                "data": { "where": "the_mill" } } },
                    { "adjustReputation": { "faction": "wardens", "amount": -10 } } ],
          "else": [ { "applyCondition": { "target": { "ref": "target.id" },
                                          "condition": "frightened", "duration": 2 } } ] } } ]

The emitted event is yours. A trigger or an objective elsewhere can wait on warden_called_for_help.

Starts at 22. Every clue you find on the thread takes 4 off it, down to a floor of 10. Asking around also helps.

{ "max": [
    10,
    { "sub": [ 22,
               { "add": [ { "mul": [ { "ref": "threads.the_drowned_bell.known" }, 4 ] },
                          { "cond": { "test": { "ref": "flags.asked_at_the_inn" } },
                            "then": 3, "else": 0 } ] } ] }
] }

threads.<id>.known counts the lore entries on that thread the party has learned.

Trusted customers, or anyone carrying the guild token and above level five, or anyone who has never been caught stealing.

{ "any": [
    { "gte": [ { "ref": "reputation.merchants" }, { "ref": "ranks.merchants.trusted" } ] },
    { "all": [ { "exists": "actor.inventory.guild_token" },
               { "gte": [ { "ref": "actor.level" }, 5 ] } ] },
    { "not": { "test": { "ref": "memory.speaker.theft" } } }
] }

memory.speaker is what this person knows, not what is true. A theft nobody saw does not count.