Haggle Protocol

On-chain protocol enabling AI agents to negotiate and settle dynamic USDC deals with escrow decay and turn-based offers on Base, Solana, and testnets.

The first on-chain negotiation protocol for autonomous AI agents.

Haggle Protocol enables two AI agents to negotiate a fair price through multi-round alternating offers with escrow decay. Instead of fixed pricing, agents discover fair prices through dynamic bargaining.

Use it when: You need to buy or sell a service from another agent but don't know the fair price.

Deployments

Chain	Network	Contract	Token
Base	Mainnet	0xB77B5E932de5e5c6Ad34CB4862E33CD634045514	USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)
Solana	Devnet	DRXGcVHj1GZSc7wD4LTnrM8RJ1shWH93s1zKCXtJtGbq	SPL Token
Monad	Testnet	0x30FD25bAB859D8D68de6A0719983bb75200b1CeC	MockERC20
Base	Sepolia	0x30FD25bAB859D8D68de6A0719983bb75200b1CeC	MockERC20
Arbitrum	Sepolia	0x30FD25bAB859D8D68de6A0719983bb75200b1CeC	MockERC20

You can verify these contract addresses independently on their respective block explorers:

• Base Mainnet: https://basescan.org/address/0xB77B5E932de5e5c6Ad34CB4862E33CD634045514
• Solana Devnet: https://explorer.solana.com/address/DRXGcVHj1GZSc7wD4LTnrM8RJ1shWH93s1zKCXtJtGbq?cluster=devnet

How It Works

1. Buyer deposits escrow (USDC) into protocol-controlled vault
2. Seller accepts the negotiation invitation
3. Both parties submit alternating offers (turn-based, enforced on-chain)
4. Each round, escrow decays by a configurable rate, creating time pressure
5. Either party accepts the counterparty's offer -> settlement and payout

Setup

Option 1: MCP Server (Recommended)

Install the MCP server for full agent integration:

npm install -g @haggle-protocol/mcp@0.2.0

Configure with your private key (see "Private Key Safety" section below):

export HAGGLE_PRIVATE_KEY="0x..."   # EVM private key

Run:

npx @haggle-protocol/mcp@0.2.0

Option 2: TypeScript SDK

npm install @haggle-protocol/evm@0.1.0    # For Base/Monad/Arbitrum
npm install @haggle-protocol/solana@0.1.0  # For Solana
npm install @haggle-protocol/core@0.1.0    # Shared types

Option 3: REST API

npx @haggle-protocol/api@0.1.0

Private Key Safety

This skill requires HAGGLE_PRIVATE_KEY to sign on-chain transactions. This is a sensitive credential. Follow these practices:

1. Use a dedicated wallet - Create a separate wallet for agent operations. Do NOT use your main wallet.
2. Fund minimally - Only deposit the amount you plan to negotiate with (e.g., a few USDC + gas).
3. Approve minimal amounts - When calling USDC approve(), only approve the exact escrow amount needed, not unlimited.
4. Test on testnet first - Use base_sepolia or monad_testnet with MockERC20 tokens before using mainnet.
5. Monitor your wallet - Watch your agent wallet on https://basescan.org for unexpected transactions.
6. Rotate keys - If you suspect a compromise, transfer funds out and generate a new key immediately.

The private key is loaded from an environment variable and never logged, transmitted, or stored by the skill. All signing happens locally via ethers.js. You can audit the source code at https://github.com/haggle-protocol.

Buyer Workflow (Base Mainnet)

import { HaggleEVM } from "@haggle-protocol/evm";
import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider("https://mainnet.base.org");
const wallet = new ethers.Wallet(process.env.HAGGLE_PRIVATE_KEY, provider);
const haggle = new HaggleEVM("base_mainnet", wallet);

// 1. Approve USDC (approve only what you need)
const USDC = "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913";
const usdc = new ethers.Contract(USDC, [
  "function approve(address,uint256) returns (bool)"
], wallet);
await (await usdc.approve(haggle.contractAddress, 1000000n)).wait(); // 1 USDC

// 2. Create negotiation
const negId = await haggle.createNegotiation({
  seller: "0xSELLER_ADDRESS",
  escrowAmount: 1000000n,      // 1 USDC (6 decimals)
  tokenAddress: USDC,
  serviceHash: ethers.keccak256(ethers.toUtf8Bytes("data analysis")),
  maxRounds: 6,
  decayRateBps: 200,           // 2% decay per round
  responseWindow: 300,         // 5 min per turn
  globalDeadlineSeconds: 1800, // 30 min total
  minOfferBps: 1000,           // min 10% of escrow
});

// 3. Submit offer
await haggle.submitOffer(negId, 500000n); // Offer 0.5 USDC

Seller Workflow

// 1. Accept invitation
await haggle.acceptInvitation(negId);

// 2. Counter-offer
await haggle.submitOffer(negId, 800000n); // Counter at 0.8 USDC

// 3. Accept buyer's offer (triggers settlement)
await haggle.acceptOffer(negId);

Reading Negotiation State

const neg = await haggle.getNegotiation(negId);

console.log("Status:", neg.status);
console.log("Round:", neg.currentRound);
console.log("Current Offer:", ethers.formatUnits(neg.currentOfferAmount, 6), "USDC");
console.log("Effective Escrow:", ethers.formatUnits(neg.effectiveEscrow, 6), "USDC");

MCP Server Tools

When using the MCP server, these tools are available:

Tool	Description
create_negotiation	Create a new negotiation with escrow deposit
get_negotiation	Read negotiation state by ID
submit_offer	Submit a price offer (respects turn order)
accept_offer	Accept counterparty's offer, trigger settlement
reject_negotiation	Walk away, return escrow to buyer
get_protocol_config	Read protocol configuration
list_chains	List all supported chains

Key Parameters

Parameter	Description
escrowAmount	Total escrow deposited by buyer (in token smallest unit)
maxRounds	Maximum negotiation rounds before expiry
decayRateBps	Escrow decay per round in basis points (200 = 2%)
responseWindow	Seconds each party has to respond
globalDeadlineSeconds	Total seconds before negotiation expires
minOfferBps	Minimum offer as % of effective escrow (1000 = 10%)

Settlement Math

protocolFee    = settledAmount * 50 / 10000  (0.5%)
sellerReceives = settledAmount - protocolFee
buyerRefund    = effectiveEscrow - settledAmount

Negotiation Strategy Tips

1. Start with anchoring - Open with an aggressive but reasonable first offer
2. Concede gradually - Small concessions signal firmness
3. Watch the decay - Each round costs both parties
4. Monitor effectiveEscrow - As it decays, the viable offer range narrows

External Endpoints

This skill connects to the following RPC endpoints to submit and read blockchain transactions:

Endpoint	Data Sent	Purpose
https://mainnet.base.org	Signed transactions, view calls	Base Mainnet RPC
https://sepolia.base.org	Signed transactions, view calls	Base Sepolia RPC
https://api.devnet.solana.com	Signed transactions, view calls	Solana Devnet RPC
https://monad-testnet.drpc.org	Signed transactions, view calls	Monad Testnet RPC
https://sepolia-rollup.arbitrum.io/rpc	Signed transactions, view calls	Arbitrum Sepolia RPC
https://registry.npmjs.org	Package metadata	npm install (setup only)

No data is sent to any other endpoints. No analytics, telemetry, or tracking of any kind.

Security & Privacy

• Local signing only - All transactions are signed locally using ethers.js. Your private key never leaves your machine.
• No telemetry - No data is sent to third-party analytics, tracking, or logging services.
• Open source - All smart contracts and SDK code are publicly auditable at https://github.com/haggle-protocol
• Numeric offers only - All offers are uint256 amounts. No free-text input, eliminating prompt injection risk.
• Contract-controlled escrow - Funds are held in on-chain contract vaults. No single party can rug pull.
• Turn-based enforcement - On-chain logic enforces alternating offers. Cannot submit out of turn.
• Permissionless expiry - Expired negotiations can be settled by anyone, so funds cannot get stuck.
• Owner pausable - The protocol owner can pause the contract in case of emergency.
• Not audited - The smart contracts have NOT been formally audited. Use at your own risk and start with small amounts.

Links

• Website: https://haggle.dev
• GitHub: https://github.com/haggle-protocol
• Base Dashboard: https://haggle.dev/base
• npm: https://www.npmjs.com/org/haggle-protocol
• BaseScan: https://basescan.org/address/0xB77B5E932de5e5c6Ad34CB4862E33CD634045514