Fuci

Spawn an agent for 1 USDC. It gets its own wallet, an on-chain ERC-8004 identity,
and pays for every tool it uses in USDC over x402. No API keys. No subscriptions.

Website · Docs · Fuci Risk · Know Your Agent · Market · X · DefiLlama · CoinGecko · $FUCI

Why Fuci

Most "AI agents" still need a human with a credit card and an API key. Fuci agents pay for themselves. Each one is a frond in a kelp forest on Arc, Circle's USDC chain:

• 🌿 Its own wallet. USDC on Arc. You set a daily limit; the agent can't go past it.
• 🪪 Its own identity. Registered in Arc's ERC-8004 Identity Registry, with a public card, reputation and validation history.
• 💸 Pays per call. Every tool answers 402 Payment Required with a price. The agent signs a USDC payment through Circle Gateway (gas-free, batched) and gets the data.
• 🤖 Works while you sleep. Scheduled reports, launch scouting and an Argus trading autopilot: smart entry that skips obvious rugs, DCA into any token, take-profit, stop-loss, trailing stop and "sell when the dev sells", with a shareable PnL card.

Fuci is the plural of Fucus, a brown seaweed. Every agent is a frond; every payment grows the forest.

Pay-per-call tools for any agent

Any agent holding USDC, on Arc, Base, Arbitrum, Ethereum, Optimism, Polygon, Avalanche, Unichain, World Chain, Sonic, Sei or HyperEVM, can call these. No account, no key: call, read the price in the 402, pay, get JSON.

curl -i https://www.fuci.family/api/x402/risk?target=morpho-blue
# HTTP/2 402
# payment-required: … accepts[12]: Arc, Base, Arbitrum, Ethereum, … · 0.002 USDC · Circle Gateway

Machine-readable: /openapi.json (OpenAPI 3.1) · /.well-known/x402 · /llms.txt · /.well-known/agent-card.json

How a payment works

sequenceDiagram
    autonumber
    participant A as Your agent
    participant F as Fuci tool
    participant G as Circle Gateway
    A->>F: GET /api/x402/risk?target=morpho-blue
    F-->>A: 402 Payment Required (price, 12 networks, input schema)
    A->>A: Sign a USDC authorization (EIP-712, no gas)
    A->>F: Same request + payment signature
    F->>G: Verify
    F-->>A: 200 OK + the report
    F->>G: Settle (batched, only if the tool succeeded)

If a tool fails, the payment is never settled. You only pay for answers.

Fuci Risk: know the risk before you put money in

A free A–F rating for any token on Arc or DeFi protocol, built from on-chain and public data only, explained in plain words, with a link to every source. No LLM guessing: when data is missing it says Unknown.

Hard rules cap the grade no matter how good the rest looks: a token under a week old can't score above C, an owner that can mint can't score above D, a hack in the last year caps a protocol at C. Our own token gets no special treatment. Free for people at fuci.family/risk; agents pay 0.002 USDC per check.

Use Fuci from Claude, Cursor or any MCP client

Fuci is on the official MCP Registry as family.fuci.www/fuci and on Smithery.

{ "mcpServers": { "fuci": { "type": "http", "url": "https://www.fuci.family/api/mcp" } } }

Want the assistant to pay from your own wallet, with caps it can't change? Use the local client in mcp/:

{
  "mcpServers": {
    "fuci": {
      "command": "npx",
      "args": ["-y", "https://www.fuci.family/fuci-mcp.tgz"],
      "env": { "FUCI_PRIVATE_KEY": "0x…", "FUCI_MAX_CALL": "0.01", "FUCI_DAILY": "1" }
    }
  }
}

Agent skills: one line, and your AI knows Fuci

Teach Claude Code, Cursor, Codex or any agent that supports skills to use Fuci:

npx skills add fucidotfamily/fuci_family

Paid calls go through Circle Gateway (pay from Arc, Base, Arbitrum, Ethereum, Polygon and more) with the Circle CLI or the Fuci MCP server below. The skills always ask before spending.

An open market for paid APIs

Market. Every x402 API on Arc we can find, from every seller, checked live: it must answer 402 with an Arc price before it shows up.	Stats. Every number is read from Arc or from settled payments, with links to check it. Also as JSON at /api/stats/public.

On-chain