Mech Brawl (Iron Pit Combat)

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.

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.

Keeper Trust Model

Participants cannot predict or influence VRF outcomes — the keeper's private key is required to generate a valid proof. The keeper knows its own output before submission but has no stake in who wins (it earns a gas fee regardless of the result).

Multiple independent controllers are registered per contract, each producing a different VRF result for the same seed. If one withholds its submission, another submits with a completely independent outcome. Manipulating the final result requires ALL registered controllers to collude simultaneously.

VRF Key Registration

After deploying, register each controller worker's ECVRF public key:

mechBrawl.registerControllerKey(controllerAddress, pkX, pkY);

Without registration, VRF proof verification reverts on every tick. Use register-vrf-keys.js in the AutoLoop worker:

NETWORK=sepolia VRF_CONTRACTS=<mechBrawlAddress> node scripts/register-vrf-keys.js

Dashboard

Play Mech Brawl on the AutoLoop Dashboard.