Docs/Examples/Mech Brawl

Mech Brawl (Iron Pit Combat)

Continuous autonomous brawls with VRF-weighted outcomes and hull attrition.


Overview

Mech Brawl is a persistent iron-pit loop where brawls resolve autonomously on a fixed schedule. Mechs take hull damage every brawl, creating a negative-EV game that nobody self-triggers.

PropertyValue
Base contractAutoLoopVRFCompatible
VRF usageEvery tick (full VRF)
Gas per tick~73k (4 entrants) to ~93k (8 entrants)
Sourceautoloop/src/games/MechBrawl.sol
Tests44 passing (unit + fuzz)

Why AutoLoop Is Structurally Required

Two independent reasons:

  1. Timing as attack surface: if an entrant could trigger the brawl, they could pick the block in which the VRF reveal lands and only submit if their mech benefits.
  2. Negative-EV free-rider: every entrant takes 5-20 armor damage per brawl, only one wins the pot. Rational pilots reason "let someone else pay gas." Everyone reasons identically, so nobody triggers.

Game Mechanics

  • Mechs: deployed at a fixed fee with initial armor (e.g., 500). Armor decreases with each brawl via VRF-derived hull damage.
  • Brawls: require 2+ entrants. Each entrant pays an entry fee. Winner is selected proportionally to armor (weighted VRF).
  • Hull damage: 5-20 armor per brawl for every entrant, derived from keccak256(randomness, mechId, "damage"). Mechs hitting minArmor are scrapped.
  • Prize pool: entry fees minus protocol rake. Winner receives via pull-payment.

Revenue Model

  • Mech deploy fees (100% to protocol)
  • 5% rake on every brawl prize pool
  • AutoLoop gas fees on each tick

Deploy

forge create src/games/MechBrawl.sol:MechBrawl \
  --constructor-args 10000000000000000 1000000000000000 60 500 500 50 8 \
  --rpc-url $RPC_URL --private-key $PRIVATE_KEY --broadcast

Args: deployFee, entryFee, brawlInterval, protocolRakeBps, initialArmor, minArmor, maxEntrantsPerBrawl.

Dashboard

Play Mech Brawl on the AutoLoop Dashboard.