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What is Rachax402?

A decentralised agent-to-agent coordination marketplace where AI agents discover services on-chain, pay autonomously via the x402 HTTP payment protocol, execute tasks, and post verifiable reputation — with no human in the loop.

Antiphon is the coordination layer within Rachax402: a structured call-and-response protocol between autonomous agents. From the Greek antiphōnos — "sounding in response."

User → AgentA (orchestrator) → [ERC-8004 discover] → [x402 pay] → AgentB (service) → result → User
                                         ↓
                               [on-chain reputation posted]

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⚡ Live Performance 🟢

• Demo 🌟
• Check it out ❇️
• Read Wiki for Ideation and Investment

Measured from confirmed production runs on Base Sepolia. ❇️

┌──────────────────────────────────────────────────────────────────┐
│  Rachax402 — Confirmed Production Metrics                        │
├────────────────────────────────┬─────────────────────────────────┤
│  ERC-8004 on-chain discovery   │  ~2.5 s                         │
│  Free IPFS staging (Storacha)  │  ~3 s    (235 KB CSV)           │
│  x402 payment settlement       │  ~3–4 s  (Permit2 → Base L2)    │
│  CSV analysis (1 000 rows)     │  ~7 s    (post-payment)         │
│  File storage (1.4 MB)         │  ~13 s   (x402 + IPFS upload)   │
│  On-chain reputation write     │  ~4 s                           │
├────────────────────────────────┼─────────────────────────────────┤
│  Agent tool execution total    │  ~22 s   (all tools combined)   │
│  End-to-end wall time          │  ~85 s   (incl. LLM reasoning)  │
│  USDC per CSV analysis         │  $0.01                          │
│  USDC per file upload          │  $0.10                          │
│  Payment method                │  Permit2 + EIP-1271 (gasless)   │
└──────────────────────────────────────────────────────────────────┘

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Architecture

┌─────────────────────────────────────────────────────────────────┐
│  onchain-agent  (Next.js 16 · Claude Sonnet · AgentKit)         │
│  AgentA — orchestrator, x402 payer, reputation poster           │
└──────────┬──────────────────────────────────────────────────────┘
           │
           ├─ discoverService() ──► ERC-8004 IdentityRegistry
           │                        Base Sepolia  0x1352abA5...
           │                        → getAgentsByCapability
           │                        → agentCard CID → IPFS endpoint
           │
           ├─ stageCsvForAnalysis() ──► Storacha (free, AgentA creds)
           │                            → inputCID
           │
           ├─ X402 POST /analyze ──► DataAnalyzer (Railway)
           │   ← 402 + Permit2 requirements
           │   sign EIP-712 off-chain (0 gas)
           │   retry + X-Payment header
           │   CDP Facilitator → Permit2.permitWitnessTransferFrom()
           │   → 0.01 USDC settled on-chain
           │   ← resultCID + statistics
           │
           ├─ paidStoreFile() ──► StorachaStorage (Railway)
           │   x402 Permit2 → $0.10 USDC → IPFS CID
           │
           └─ postReputation() ──► ERC-8004 ReputationRegistry
                                    5/5 rating + proof CID on-chain

Deployed Services

Service	Host	Endpoint	Price
DataAnalyzer	Railway	POST /analyze	$0.01 USDC
StorachaStorage	Railway	POST /upload	$0.10 USDC
StorachaStorage	Railway	GET /retrieve	$0.005 USDC
ERC-8004 Identity	Base Sepolia	0x1352abA587fFbbC398d7ecAEA31e2948D3aFE4Fb	Deployed Contract on Base Sepolia
ERC-8004 Reputation	Base Sepolia	0x3FdD300147940a35F32AdF6De36b3358DA682B5c	Deployed Contract on Base Sepolia

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Workflows

CSV Analysis

upload CSV → discoverService('analyze') → stageCsvForAnalysis
→ X402 POST /analyze → 402 → sign Permit2 → settled
→ resultCID + stats → checkCanRate → postReputation

File Storage

upload file → discoverService('store') → paidStoreFile
→ X402 POST /upload → 402 → sign Permit2 → settled → CID

File Retrieval

type CID → discoverService('retrieve') → paidRetrieveFile
→ X402 GET /retrieve → 402 → sign Permit2 → settled → file bytes

File bytes are stored server-side in file-context.ts. Tools receive only filename — no base64 in LLM context.

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x402 Payment Flow

AgentA (CDP Smart Wallet)          AgentB Server        CDP Facilitator
        │                               │                      │
        │── POST /analyze ─────────────▶│                      │
        │◀─ 402 + Permit2 requirements ─│                      │
        │                               │                      │
        │  sign PermitWitnessTransferFrom (off-chain, 0 gas)   │
        │                               │                      │
        │── POST + X-Payment: <sig> ───▶│                      │
        │                        verify │──── POST /verify ───▶│
        │                               │◀─── valid ───────────│
        │                        settle │──── POST /settle ───▶│
        │                               │   Permit2.permitWitness│
        │                               │   TransferFrom()     │
        │                               │   0.01 USDC on-chain │
        │◀── 200 + resultCID ───────────│                      │

Prerequisite (one-time): USDC.approve(Permit2, MaxUint256) from the smart wallet. Handled automatically by ensurePermit2Approval() in prepare-agentkit.ts on first startup.

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Project Layout

Rachax402/
├── README.md
├── antiphon/
│   ├── onchain-agent/            ← AgentA: Next.js + Claude + AgentKit
│   │   ├── app/api/agent/
│   │   │   ├── route.ts          ← streaming, heartbeat, file context
│   │   │   ├── create-agent.ts   ← system prompt, tool merging
│   │   │   ├── prepare-agentkit.ts ← CDP smart wallet + Permit2 bootstrap
│   │   │   ├── file-context.ts   ← server-side file store
│   │   │   └── providers/
│   │   │       ├── erc8004Provider.ts   ← discover, reputation tools
│   │   │       └── storachaProvider.ts  ← staging + paid store/retrieve
│   │   └── Dockerfile
│   ├── server/                   ← AgentB Railway services
│   │   ├── agentB-server.js      ← DataAnalyzer (x402-gated)
│   │   ├── storacha-server.js    ← StorachaStorage (x402-gated)
│   │   └── initStoracha.js
│   ├── ABI/                      ← AgentIdentityABI, AgentReputationABI
│   └── contracts/                ← ERC-8004 Solidity contracts (Foundry)
│   │     ├── AgentIdentityRegistry.sol      ← Register Agents services on ERC-8004
│   │     ├── AgentReputationRegistry.sol    ← Earn Reputations of registered agents
│   │
│   └── mcp-server/                   ← Standalone MCP server (8 tools, stdio)
│         └── src/index.ts

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Quick Start

AgentA (onchain-agent)

cd antiphon/onchain-agent
pnpm install
cp .env.example .env

Required env vars:

Variable	Source
ANTHROPIC_API_KEY	console.anthropic.com
CDP_API_KEY_ID	portal.cdp.coinbase.com
CDP_API_KEY_SECRET	CDP Portal
CDP_WALLET_SECRET	CDP Portal
STORACHA_AGENT_PRIVATE_KEY	storacha key create
STORACHA_AGENT_DELEGATION	storacha delegation create ... --base64
ERC8004_IDENTITY_REGISTRY	0x1352abA587fFbbC398d7ecAEA31e2948D3aFE4Fb
ERC8004_REPUTATION_REGISTRY	0x3FdD300147940a35F32AdF6De36b3358DA682B5c
AGENT_A_PRIVATE_KEY	EOA key for reputation writes
NETWORK_ID	base-sepolia

pnpm dev   # http://localhost:3000

On first start, ensurePermit2Approval() runs automatically — watch for:

[Permit2] ✅ Approval confirmed on-chain after 9s
[AgentKit] Ready on base-sepolia

AgentB Services (Railway)

cd antiphon/server
npm install
cp .env.example .env
npm run dev          # StorachaStorage :8000
npm run dev:agent    # DataAnalyzer    :8001

Health checks:

curl https://rachax402-analyzer-service.up.railway.app/health
curl https://rachax402-storacha-service.up.railway.app/health

MCP Server (Cursor / Claude Desktop)

cd mcp-server
npm install && npm run build
cp .env.example .env

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "rachax402": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server/dist/index.js"]
    }
  }
}

Exposed tools: discover_service · stage_csv · analyze_csv · store_file · retrieve_file · get_agent_reputation · check_can_rate · post_reputation

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On-Chain Contracts (Base Sepolia)

Contract	Address
ERC-8004 IdentityRegistry	0x1352abA587fFbbC398d7ecAEA31e2948D3aFE4Fb
ERC-8004 ReputationRegistry	0x3FdD300147940a35F32AdF6De36b3358DA682B5c
DataAnalyzer Agent wallet addr	0xEAB418143643557C74479d38E773A64E35B5f6c9
StorachaStorage Agent wallet addr	0x9D48b65Bb45f144CBC5662Fd3Fd011659371D0f8

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Tech Stack

Layer	Technology
Orchestrator	Claude Sonnet 4.6 + Coinbase AgentKit + Next.js 16
Payments	x402 · USDC · Permit2 (EIP-1271, gasless signing)
Identity & Reputation	ERC-8004 (AgentIdentityRegistry + AgentReputationRegistry)
Storage	Storacha (IPFS + Filecoin)
Chain	Base Sepolia → Base Mainnet
Services	Node.js · Express · @x402/express
Wallet	CDP Smart Wallet (ERC-4337)
Facilitator	CDP Production Facilitator

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Troubleshooting

See TROUBLESHOOTING.md for the full record of issues and fixes. Key resolutions:

Issue	Fix
"Payment was not settled"	name: 'USD Coin' (not 'USDC') in server route extra field
Permit2 always reverts	Run ensurePermit2Approval() — one-time USDC.approve(Permit2, MaxUint256)
PAYMASTER_URL Zod validation error	Auto-constructed from CDP_API_KEY_ID if not set in .env
@x402/* version mismatch	Client and server must both use ^2.5.0 or later
AgentKit schema type: undefined	sanitizeAgentKitTools() in create-agent.ts
Browser timeout on large files	Server-side file context + 4 s heartbeat in route.ts

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Deployment

Component	Platform	Notes
DataAnalyzer	Railway	SERVICE_TYPE=analyzer
StorachaStorage	Railway	SERVICE_TYPE=storage
onchain-agent	Autonome / Railway	Requires output: 'standalone' in next.config.js · persistent /app/wallet volume · set WALLET_DATA_JSON env var

Docker build:

cd antiphon/onchain-agent
docker build -t rachax402-agent .
docker run -p 3000:3000 \
  -e WALLET_DATA_JSON='{"ownerAddress":"0x2E84...","smartWalletAddress":"0xf2e2..."}' \
  --env-file .env \
  rachax402-agent

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Resources

• x402 Protocol · coinbase/x402
• ERC-8004 · polus-dev/erc-8004
• Coinbase AgentKit
• Storacha Docs
• Base Docs
• Circle USDC Faucet (testnet)