Stigmetry Agent Payments

AI Agentic Commerce & Payments on Arc — built with Circle's App Kits and MCP.

Arc is Circle's Layer-1 blockchain where USDC is the native gas token. This repo implements the full agentic economy stack:

• ERC-8004 — On-chain AI agent identity & reputation registry
• ERC-8183 — Programmable job lifecycle with USDC escrow
• Circle App Kits — Send, Bridge, Swap, Unified Balance
• Circle Wallets API — Developer-controlled, gas-sponsored SCA wallets
• MCP Server — Expose Arc agent tools to Claude and any MCP client

---

Architecture

┌─────────────────────────────────────────────────────┐
│                  MCP Client (Claude)                 │
│              arc_create_job / arc_accept_job...      │
└────────────────────┬────────────────────────────────┘
                     │ MCP (stdio / HTTP)
┌────────────────────▼────────────────────────────────┐
│              Arc Agent MCP Server                    │
│         src/mcp/server.ts — 12 tools                 │
└──────┬─────────────────────────────┬────────────────┘
       │                             │
┌──────▼──────┐             ┌────────▼──────────┐
│  Agent      │             │  Payments         │
│  Identity   │             │  App Kit          │
│  (ERC-8004) │             │  Wallets API      │
└──────┬──────┘             └────────┬──────────┘
       │                             │
┌──────▼─────────────────────────────▼──────────┐
│              Arc Testnet                       │
│    Chain ID 5042002 · USDC native gas          │
│    RPC: https://rpc.testnet.arc.network        │
└───────────────────────────────────────────────┘
       │
┌──────▼──────────────────────────────────────┐
│  Contracts (Solidity 0.8.24)                 │
│  AgentIdentity.sol — ERC-8004               │
│  AgentJob.sol      — ERC-8183               │
└─────────────────────────────────────────────┘

---

Live Deployments

Arc Testnet (Chain ID 5042002)

Contract	Address	Standard
AgentIdentity	0x5Bef356f...3b8233	ERC-8004
AgentJob	0xD698d15F...5094	ERC-8183
USDC (native ERC-20)	0x3600...0000	ERC-20

Full deployment details: deployments/arc-testnet.json

---

Quick Start

1. Install dependencies

npm install

2. Configure environment

cp .env.example .env

Fill in .env:

Variable	Where to get it
CIRCLE_API_KEY	console.circle.com → API Keys
CIRCLE_ENTITY_SECRET	Generated once via Circle SDK setup
AGENT_PRIVATE_KEY	cast wallet new (Foundry) or Circle Wallets
ARC_RPC_URL	https://rpc.testnet.arc.network (default)

3. Get testnet USDC

Visit https://faucet.circle.com, select Arc Testnet, paste your wallet address.

4. Deploy contracts

# Install Foundry: curl -L https://foundry.paradigm.xyz | bash && foundryup
chmod +x scripts/deploy.sh
./scripts/deploy.sh

This deploys AgentIdentity and AgentJob, then writes the addresses to your .env.

5. Run the demo

npm run dev
# or
npx tsx src/agent/index.ts

The demo:

1. Checks your USDC balance
2. Registers an AI agent identity on-chain (ERC-8004)
3. Posts a job with 1 USDC in escrow (ERC-8183)
4. Has the agent accept and submit a deliverable
5. Releases the USDC payment

---

MCP Server

Run the MCP server to expose Arc tools to Claude:

npm run mcp

Add to Claude Desktop

{
  "mcpServers": {
    "arc-agent": {
      "command": "npx",
      "args": ["tsx", "/path/to/arc-agent-payments/src/mcp/server.ts"],
      "env": {
        "AGENT_PRIVATE_KEY": "0x...",
        "CIRCLE_API_KEY": "...",
        "AGENT_IDENTITY_REGISTRY_ADDRESS": "0x...",
        "AGENT_JOB_CONTRACT_ADDRESS": "0x..."
      }
    }
  }
}

Add to Claude Code

claude mcp add --transport stdio arc-agent npx tsx src/mcp/server.ts

Available MCP Tools

Tool	Description
arc_register_agent	Register AI agent identity (ERC-8004)
arc_get_agent	Get agent details and reputation
arc_my_agents	List your agent token IDs
arc_create_job	Post a job with USDC escrow (ERC-8183)
arc_accept_job	Agent accepts a job
arc_submit_deliverable	Submit work with on-chain hash
arc_complete_job	Client accepts + releases USDC
arc_get_job	Get job status and details
arc_balance	Check USDC balance
arc_send_usdc	Send USDC on Arc
arc_create_wallet	Create Circle developer wallet
arc_request_faucet	Request testnet USDC

---

Testnet Resources

Resource	URL
RPC	https://rpc.testnet.arc.network
Explorer	https://testnet.arcscan.app
Faucet	https://faucet.circle.com
Chain ID	5042002
Native currency	USDC (6 decimals)

---

Project Structure

agent-payments/
├── contracts/
│   ├── interfaces/
│   │   ├── IERC8004.sol        # Agent identity interface
│   │   └── IERC8183.sol        # Job lifecycle interface
│   ├── AgentIdentity.sol       # ERC-8004 implementation
│   └── AgentJob.sol            # ERC-8183 implementation
├── src/
│   ├── agent/
│   │   ├── index.ts            # Demo entry point
│   │   ├── identity.ts         # ERC-8004 TypeScript client
│   │   └── commerce.ts         # ERC-8183 TypeScript client
│   ├── payments/
│   │   ├── appkit.ts           # Circle App Kit (Send/Bridge/Swap)
│   │   └── wallets.ts          # Circle Wallets API
│   ├── mcp/
│   │   └── server.ts           # MCP server (12 tools)
│   └── config.ts               # Environment + chain config
├── scripts/
│   └── deploy.sh               # Contract deployment script
├── foundry.toml
├── package.json
├── tsconfig.json
└── .env.example

---

Stack

• Chain: Arc Testnet (Circle, Chain ID 5042002)
• Contracts: Solidity 0.8.24, Foundry
• SDK: Viem v2, Circle App Kit, Circle Wallets API
• MCP: @modelcontextprotocol/sdk
• Runtime: Node.js 20+, TypeScript 5.4

References

• Arc Docs
• Arc Testnet Explorer
• Circle Developer Console
• Circle App Kit Docs
• ERC-8004 Spec
• ERC-8183 Spec