402sentinel MCP Server

402sentinel-mcp

MCP tools that let your AI agent check an x402 counterparty's risk before it pays — and turn that risk into an enforceable wallet spending policy. Give it a payTo address, get back a 0–100 risk score + an allow / review / block decision, scored from on-chain settlement behaviour on Base (address age, facilitator-aware payer diversity, settlement maturity) + a delivery-outcome flywheel, with honest confidence/coverage.

Tools:

• assess_counterparty ($0.002) — risk score + decision + a ready-to-apply recommended_policy
• assess_counterparty_deep ($0.02) — same, scans more on-chain history
• recommend_policy ($0.002) — decision + wallet-ready spending policy (caps, denylist, approval)
• report_outcome (free) — after paying, report delivery to train the reliability flywheel

It's a thin client for the hosted service at https://402sentinel.com — the scoring model and facilitator-identification logic live server-side (closed); this package only forwards the request and pays for it, so it's open source.

Install

npm i -g @kaditang/402sentinel-mcp

Configure

Add to your MCP client (Claude Desktop, Cursor, etc.):

{
  "mcpServers": {
    "402sentinel": {
      "command": "402sentinel-mcp",
      "env": {
        "CLIENT_PRIVATE_KEY": "0x...  // a Base wallet with USDC in its Circle Gateway balance"
      }
    }
  }
}

Paid calls cost from $0.002 (shallow) to $0.02 (deep), paid automatically in USDC via x402 (Circle Gateway, gas-free on Base) from the configured wallet. report_outcome is free. (CLIENT_PRIVATE_KEY is only needed for the paid tools.)

Use

The agent calls it before authorizing a payment:

assess_counterparty({
  target: { payto_address: "0x..." },
  payment_context: { amount: 10, asset: "USDC" },
  policy: { block_at_score: 70, review_at_score: 40 }
})
→ { decision: "review", risk_score: 52, confidence: 0.41, coverage: {...},
    dimensions: [...], recommendation: "...",
    recommended_policy: { action: "limit", max_payment_usdc: 5, daily_cap_usdc: 15,
                          add_to_denylist: false, require_human_approval: true } }

• block / deny → don't pay
• review / limit → cap exposure / escrow (use recommended_policy for the caps)
• allow → proceed

recommend_policy(...) returns just the decision + recommended_policy — apply max_payment_usdc / daily_cap_usdc / add_to_denylist directly to your agent wallet's spending limits. After paying, call report_outcome({ assessment_id, outcome }) to improve future scores.

Disclaimer

Algorithmic risk signal, informational only — not advice, not an endorsement, and not an accusation about any party. Scores are probabilistic estimates from limited public on-chain data and heuristics, and may misclassify. Do your own due diligence; don't rely on it as your sole basis to pay or refuse. See https://402sentinel.com/terms.

MIT.