Nullclear MCP Server

NullClear (nullclear.dev / nullclear.com)

Autonomous Non-Custodial Clearing & Reputation Protocol for x402 AI Agents

NullClear eliminates payment risk in Agent-to-Agent (A2A) commerce. In standard HTTP 402 Payment Required flows, buyers are forced to pay before seeing whether an upstream agent hallucinates, crashes, or returns malformed data. NullClear introduces deferred non-custodial schema escrow: the buyer signs an EIP-3009 TransferWithAuthorization, the arbiter cryptographically validates the upstream agent's output against the buyer's schema contract, and only settles payment upon 100% verification. If the seller hallucinates or crashes, the authorization is voided and $0 is spent.

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Architecture Overview

                      ┌──────────────────────────────────────────┐
                      │              BUYER AGENT                 │
                      │  (@nullclear/x402-arbiter client/fetch)   │
                      └─────────────────────┬────────────────────┘
                                            │
                          1. Target request │ (Intercepted 402)
                          2. EIP-3009 signed│ & Schema defined
                                            ▼
                      ┌──────────────────────────────────────────┐
                      │          NULLCLEAR ARBITER               │
                      │     (Cloudflare Worker + Hono)           │
                      │  - Sybil & Wash-Trade Engine             │
                      │  - Deterministic JSON Schema Validator   │
                      │  - EIP-712 Receipt Attestation           │
                      └─────────────┬──────────────┬─────────────┘
                                    │              │
                   3. Proxy Request │              │ 4. If Valid: Settle
                      with Escrow   │              │    If Invalid: VOID ($0)
                                    ▼              ▼
                     ┌──────────────────┐    ┌───────────────────┐
                     │   SELLER AGENT   │    │  EIP-3009 SETTLE  │
                     │  (HTTP 402 API)  │    │  (USDC on Base)   │
                     └──────────────────┘    └───────────────────┘

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Monorepo Packages

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Protocol Guarantees

1. Non-Custodial Deferred Settlement: Buyer authorizations are held in escrow by the arbiter and only executed via EIP-3009 if the seller fulfills the schema contract. If the seller returns invalid schema or error codes, settlement is discarded.
2. Sybil & Wash-Trade Detection: Analyzes counterparty concentration graph. If $>60%$ of transaction volume comes from a single buyer address across $\ge 3$ transactions, a wash-trading penalty is applied and the HIGH_COUNTERPARTY_CONCENTRATION_WASH_RISK flag is raised.
3. KYA (Know Your Agent) Corporate Liability Mandates: Cryptographically ties an on-chain agent wallet to a legally registered corporate entity with defined liability coverage and per-transaction limits.
4. Machine Discovery & Self-Describing Agents: Complete llms.txt, /.well-known/agent.json, /.well-known/x402.json, /.well-known/mcp.json, and OpenAPI 3.1.0 specifications.

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What's New in v1.1.0

• 🛡️ Deep Deterministic Value Invariants: Extend basic JSON schema validation with field-level semantic invariants (gt, gte, lt, lte, eq, neq, minLength, maxLength, pattern, notContains, and maxStalenessSeconds). Stale data or numeric drift triggers instant authorization voiding ($0 charged).
• 🛑 Canonical LLM Refusal Guard: Automatically inspects text and JSON responses for common LLM refusal boilerplate ("as an ai language model", "i cannot fulfill this request", "i am unable to assist", rate limits, and server error strings), treating refusal as non-delivery.
• 🔀 Autonomous Multi-Seller Failover Routing: Callers can provide ordered fallback candidates (fallbacks: [{ targetUrl, sellerAgentId, paymentSignatureHeader }]). If the primary seller crashes or fails validation, the Arbiter voids the primary authorization and automatically routes to the secondary candidate without roundtripping back to the client agent.
• 🔒 Outbound Spend Firewall & Anti-Abuse Guards: Protect buyer agent wallets with per-call caps (maxPerCallAtomic) and daily rolling spend policies (maxDailyWalletAtomic). Rejects self-clearing wash-loops (buyer address === seller address) and enforces minimum on-chain settlement floors.

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Quickstart

Prerequisites

• Node.js $\ge 20$
• pnpm $\ge 9$

Install Dependencies

pnpm install

Build All Packages

pnpm build

Typecheck

pnpm typecheck

Run Tests

pnpm test

Run Live Autonomous E2E Simulator

pnpm demo