NullClear Arbiter lets an assistant discover x402 APIs, audit Base tokens and wallets, and make escrowed HTTP 402 payments with receipts.
What you can do
Search a directory of audited x402 and ERC-8004 APIs by topic, category, uptime or latency, with protected proxy URLs
Audit Base ERC-20 tokens for honeypot risk, taxes, verified bytecode and x402 compatibility
Score wallets and agents for sanctions, Sybil wash-trading flags and counterparty reputation
Fetch spread-verified crypto spot prices with cryptographic invariant receipts
Fetch URLs through guards against refusals, 5xx errors and empty JSON, with execution receipts
Execute x402-gated API calls through deferred schema escrow, and verify agent KYA mandates and transaction limits
When to use it
Useful when an assistant needs to call paid x402 HTTP APIs and wants payment released only if the response matches a schema, or when it needs quick risk checks on Base tokens, wallets and agent reputation before transacting.
Requirements
Runs as a remote endpoint or as a local npm package over stdio. The README's config example sets ARBITER_URL and BUYER_PRIVATE_KEY; the manifest declares no authentication, environment variables or headers. Some tools are described as working with zero configuration and a limited number of free daily calls.
Before you install
The README config asks for BUYER_PRIVATE_KEY, a wallet private key that can move funds; prefer a dedicated low-balance key. Escrow calls and paid API usage can spend real crypto, and the server sends queries about tokens, wallets and URLs to NullClear's own services.
Enable the server for the chats that should use its tools.
Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.
Use with an agent
Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.
Read https://sourceweft.com/mcp/io.github.mithgalalfayez%2Fnullclear/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.
Model Context Protocol (MCP) server enabling autonomous AI agents (Claude Desktop, Cursor, Gemini, OpenAI Agents) to safely transact over HTTP 402 with NullClear deferred escrow and reputation scoring.
Exposed Tools
nullclear_check_reputation: Query an agent's on-chain trust score, clearing reliability, and Sybil wash-trade penalty flags.
nullclear_escrow_x402_call: Perform an HTTP 402 call with deferred non-custodial schema escrow, guaranteeing $0 spent if the counterparty agent fails or returns malformed data.
nullclear_verify_kya_mandate: Verify an agent's legal corporate liability backing and per-transaction limits.
Configuration
Add to your MCP client config (e.g., claude_desktop_config.json):
Search the live NullClear Ecosystem Directory for audited, high-uptime x402 & ERC-8004 APIs by topic/keyword, category, minimum uptime, or max latency. Automatically returns the NullClear-protected Zero-Loss Proxy URL ('https://api.nullclear.dev/https://...') for each endpoint.
Audit any Base ERC-20 token address for honeypot risk, buy/sell taxes, verified bytecode, and x402 compatibility via NullClear Bazaar. Works out-of-the-box with zero configuration (10 free daily calls included).
ParameterstokenAddressrequired
nullclear_wallet_risk_score
Wallet & Agent Sanctions / Sybil Risk Score
Check any wallet or agent address on Base for OFAC sanctions, Sybil wash-trading concentration flags, and ERC-8004 counterparty reputation. Works out-of-the-box with zero configuration (10 free daily calls included).
ParameterschainIdwalletAddressrequired
nullclear_crypto_market_oracle
Spread-Verified Crypto Market Price Oracle
Fetch multi-exchange spread-verified crypto spot prices (ETH/USDC, BTC/USDC, SOL/USDC, BASE/USDC) with cryptographic NullClear invariant receipts. Works out-of-the-box with zero configuration (10 free daily calls included).
Parameterspairrequired
nullclear_safe_fetch
Auto-Guarded URL Fetcher (Zero Schema Required)
Zero-config drop-in URL fetcher with automatic Canonical LLM Refusal Guard, HTTP 5xx crash guard, empty-JSON guard, and cryptographic execution receipt. Protects agents from hallucinated or broken API responses.
Parametersurlrequiredbodymethod
nullclear_escrow_x402_call
Execute Escrowed x402 Call with Invariants
Execute an x402-gated HTTP API call through NullClear deferred schema escrow. Guarantees payment is only settled if upstream returns valid data matching your schema contract. Supports 10 free daily trial calls with zero wallet setup.
Inspect an AI agent's trust score (0-100), clearing reliability, Sybil wash-trade penalty flags, and corporate KYA backing on Base
ParametersagentIdrequiredchainId
nullclear_verify_kya_mandate
Verify Corporate KYA Mandate & Limits
Verify an agent's Know Your Agent (KYA) corporate liability mandate, active validity, and whether a proposed transaction amount is within corporate limits
How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.