Gameplay / non-genetic

Horse care: gated healing, bond & herds

Three non-genetic systems that apply to every horse and share one slow tick (server/HorseCareHandler): passive healing gated on nearby water and food, a per-horse bond number that changes how a horse behaves toward its owner, and an emergent herd grouping. First slice built 2026-09-02, not play-tested — checklist in verification. This page is the single source of truth for the machinery; what is still missing is on the roadmap.

Where it lives

• data/HorseCareAttachment — the per-horse state (bond, herd id, the bondToday / dayStamp daily-cap pair, a bondTicks fractional accumulator, a togetherTicks herd-formation counter). Registered as horsegenetics:horse_care in ModAttachments, copyOnDeath, serialized by its own MAP_CODEC.
• server/HorseCareHandler — the shared tick (EntityTickEvent.Post, every 30 ticks, phase-staggered by tickCount + entityId), plus the PlayerInteractEvent.EntityInteract hook for feed-bond and the EntityJoinLevelEvent hook that adds the goal.
• server/BondFollowGoal — the one AI goal, added at priority 4 to every Horse, that reads the bond tier.
• network/HorseCareSyncPayload → client/ClientHorseCareCache — bond + in-herd flag pushed to trackers on change and on start-tracking, shown on the horse information screen's Overview tab (the i button on the horse inventory).
• Block tags data/horsegenetics/tags/block/horse_water.json and horse_food.json.

1. Gated healing

Vanilla horses have no passive regeneration — they heal only from being hand-fed. This adds a gated regen mechanic on top; hand-feeding is untouched and still works with no water requirement, so a stabled horse in a dry biome is never unhealable.

• Only a horse whose health is below its own max is considered — the block scan is skipped entirely otherwise, so a pen full of healthy horses costs nothing beyond the entity lookup.
• The scan is a 3-block-radius box around the horse. It heals +1 health per scan (per 30 ticks) only if it finds both:
  • a block in #horsegenetics:horse_water (water, bubble_column, water_cauldron) or any block whose fluid is in #minecraft:water;
  • a block in #horsegenetics:horse_food (hay_block, grass_block, short/tall grass, ferns, moss_block, pumpkin, melon, sugar cane, pitcher crop, and #minecraft:crops).
  Tags, not a hard-coded list, so a datapack can extend both.
• A healing horse emits a couple of HEART particles, so "it is recovering" is visible.
• Healing is toward the horse's own max health, so a genetically frail horse (when health genes land) stops at its own ceiling.
• The dimension's pens satisfy this by accident — every pen has a full water cauldron and a hay bale.

2. Bond

One goal that reads the number and returns false from canUse() below tier 1, rather than adding/removing goals as the number crosses a line. The goal is inert while the horse is leashed or ridden.

Gains — capped at +15 per Minecraft day

Riding bareback bonds exactly as well as riding saddled. This is worth saying because the obvious implementation gets it wrong: vanilla only regards a rider as the horse's controlling passenger once the horse is saddled, so the natural test (getControllingPassenger() == owner) quietly pays nothing for a bareback rider, and the two cases look identical from the saddle. They are not identical in what they mean. Bareback is how you talk a wild horse round in the first place, and it is the least equipment-mediated thing you can do with an animal — a system that rewards you for buying leather first has the relationship backwards. The gate is hasPassenger.

Hearts show whenever the bond actually moves, and stop when it cannot. They are emitted from awardBond — the one function that knows whether a point was really granted — so every path that bonds a horse gets the feedback without asking, and a horse that has hit the daily cap goes quiet. That silence is the only signal a player has that the cap exists.

A foal born to a tamed dam starts at a quarter of her bond. Starting every foal at zero made a horse born in your own stable, to your own mare, exactly as wary of you as one caught wild that morning — which is backwards. A quarter rather than all of it, because the bond is still the foal’s own to earn: this is the head start of having been born to somebody who trusts you, not an inheritance. It is written straight onto the attachment rather than through awardBond, whose job is metering against a daily cap a well-bonded dam would blow straight through.

Taming by hand

Crouch, hold out something the horse eats, look at it and keep still. It comes over, eats out of your hand, and each mouthful is one roll at taming — the same roll as being thrown off its back. Deliberately the same odds: this is a second door into taming, not an easier one, and each feed costs an item the way each mount costs a fall.

All four conditions are re-tested every tick, so breaking the pose stops the horse mid-walk, which is what teaches the mechanic. Crouching is the gesture and the thing that stops it firing whenever somebody walks past a herd holding wheat; looking picks which horse without needing a click; and stillness is checked against where you stood when it set off, so walking at the animal ends the approach and a little shuffling does not.

What counts as food is a genetic question rather than a vanilla one — a carnivore is not coming over for a carrot, and a dhampir is not coming over at all. Foals are left out for the same reason vanilla leaves them out of riding. See server/CrouchFeedGoal.

Horses come to food — and run for their favourite

Any horse drifts toward a player holding something it can eat (server/FoodTemptGoal), tamed or wild, foal or adult. No crouch, no gesture: hold food and horses take an interest. It is deliberately a drift — well under walking pace, it stops a couple of blocks short rather than pressing into you, and it ends the instant the food goes away, so a player who keeps walking simply leaves. A horse should be interested in food, not glued to it.

Its favourite food is the exception, and it runs. Twice the notice radius and more than twice the speed, so it picks its head up from across the paddock and comes at a gallop. That gap is the point of the feature: it is the only way the preference locus is visible before you have fed it. Until now you had to already know which of the favourites a horse carried in order to try it; now the horse tells you, by reacting to one item in a way it reacts to nothing else.

What counts as edible is genetic, the same test the crouch-feed goal uses — a carnivore does not come over for a carrot. A favourite overrides the diet, exactly as it does on the interaction, so a meat-eater with a taste for apples still runs at one. A ridden, leashed or led horse ignores food entirely, because all three mean somebody else is already deciding where it goes.

A saddle buys you steering, and steering is what lets you go far enough for the proximity gain and the riding gain to stack for any length of time. So a saddle is worth having; it is simply not what the horse is counting — and at the top bond tier it is not even required (below).

Bareback steering — what the top tier is for

At behaviour tier 3 (bond 81+), a horse steers without tack. Mount it bareback and it answers the reins as though saddled; drop below the tier and it stops. That is the payoff at the top of the bond ladder, and it is the one bond reward a player can feel rather than read: everything else the tiers do is the horse moving toward you on its own.

It works by lending the horse a phantom saddle for as long as the rider qualifies, because vanilla decides who may steer from inside the saddle slot and there is no other hook — server/BarebackSteeringHandler puts it on and takes it straight back off. Two consequences worth knowing: it is a real saddle while it is there, so the only thing between this and an item duplicator is the sweep that removes it (gap 156), and a horse whose bond falls loses the ability mid-ride rather than at a tidy moment.

A "day" is 24 000 game ticks (DAY_TICKS); dayStamp = getGameTime() / 24000, monotonic and reload-safe. bondToday resets when it rolls over. This answers the once-per-Minecraft-day rule for the bond side.

bondTicks converts to one bond point every 1 200 ticks (one real minute). A foal in a herd gains at double rate (the doubling is applied before the daily cap).

Setting bond for testing — /bond

/bond <0-100> sets the bond of the horse you are riding, or failing that the one you are looking at within 12 blocks; /bond on its own reports the number, the behaviour tier and whether the horse is in a herd. Dev runs only — it is registered behind the same FMLEnvironment.isProduction() guard as the test kit, in server/DebugTestWorldHandler.

It exists because every real source above is deliberately slow: a daily cap of 15 and a point per real minute of proximity means reaching tier 3 honestly is about an hour of standing about. Before this, exercising a tier meant grinding it or temporarily lowering the thresholds and rebuilding — and the second changes the thing under test.

It is not a back door. It writes through the same HorseCareHandler.syncCare every other bond source ends at, so the client is told and the bond progress tasks are credited exactly as if the horse had earned it. A command that set the number without crediting would leave the progress surface lying, and the progress surface is one of the things being tested with it.

3. Herds

• Each scan, a horse looks for another live horse within 10 blocks. togetherTicks accumulates +30 while company is present (capped at 2 × TICKS_TO_FORM_HERD) and decays −30 while alone.
• Crossing 12 000 ticks (ten minutes) with no herd yet: the horse joins a nearby horse's herd if one has an id, otherwise it mints a new UUID and pulls in every herdless neighbour that is itself at least half-way to the threshold.
• togetherTicks decaying back to 0 while in a herd → the horse leaves it (clears its id).
• Alpha is not stored. The oldest / highest-bond member is computed on demand by whatever needs it, with an explicit tiebreak, so it can't flicker.
• Herd comfort buff: restated as faster regen (the mod has no stamina resource). A horse in a herd heals +2 per scan instead of +1 when the water/food gate is met.

Performance

One handler, 30-tick interval, staggered by entity id. Per scan: one entity lookup (herd radius) always; the ~7×7×7 block scan only when the horse is hurt. The attachment is written back only when a field actually changed, and the sync packet only when bond or in-herd changed.