PayPal, guarded MCP server

x402 examples

Spending limits for AI agents, approved from your phone

Give your agents a wallet without giving them a blank cheque:

• presign-guard-wallet (npm): a viem wallet that checks every signature with presign-guard first (drainers, sanctions, unlimited approvals), keeps to your price per purchase and daily budget, and asks you on Telegram for anything above them. npm i presign-guard-wallet
• fizzl (PyPI): the same checks for Python agents, with ready-made LangChain tools. pip install fizzl
• fizzl-langchain (npm): the same checks as LangChain.js / LangGraph.js tools, with a free quick check to try them without a wallet. npm i fizzl-langchain
• presign-guard-ai-sdk (npm): safety checks as Vercel AI SDK tools. Before signing, before buying a token and before paying an x402 endpoint, the agent checks first. npm i presign-guard-ai-sdk
• presign-guard-agentkit (npm): the same for Coinbase AgentKit agents. Wrap the wallet provider in one line, and every transfer, swap, approval, permit and x402 payment is checked and kept to your limits. npm i presign-guard-agentkit
• presign-guard-solana-agent-kit (npm): the same for Solana Agent Kit agents (SendAI). Wrap the wallet in one line, and every transfer, swap and token action from every plugin is checked (instructions decoded and simulated) and kept to your SOL and USDC limits. npm i presign-guard-solana-agent-kit
• presign-guard-wallet-mcp (npm, MCP server): a wallet with spending limits for Claude, Cursor and any MCP client. The agent can pay x402 APIs and send USDC within your budget, and asks you on Telegram above it. npx -y presign-guard-wallet-mcp@0.27.1
• presign-guard-payer-screen (npm): for sellers. Screens who pays your x402 API against the OFAC SDN sanctions list before the payment settles; a listed payer gets 451 and is never charged. EVM, Solana, Algorand, XRP Ledger, no dependencies. npm i presign-guard-payer-screen
• privy-sanctions-sync: for Privy agent wallets. Keeps the condition sets behind Privy's x402 sanctions-screening policy in step with the OFAC SDN list: EVM addresses in both casings, Solana addresses plus their USDC and USDT token accounts, and XRP Ledger addresses, with a ready Privy XRPL policy for x402 payments in RLUSD. It adds before it removes and leaves a set alone when the list is stale.
• fizzl-paypal-guard (npm): for PayPal's Agent Toolkit. Refunds only for the customer in the conversation, never more than was paid, and never on a payment the customer's bank already charged back (PayPal itself lets that refund through). Daily limits on refunds, cancellations and invoices; the owner decides on refunds after the return period and on a customer who keeps asking; an AI check that the action fits what the customer asked; and Approve/Deny on Telegram above the limits. npm i fizzl-paypal-guard · live demo · video
• fizzl-paypal-guard-mcp (npm, MCP server): PayPal for Claude, Cursor and any MCP client, guarded. The same 47 tools as PayPal's own MCP server, but never more than is left of a payment, no refund while a chargeback is open, your limits on refunds, cancellations and invoices, and Approve/Deny on your phone or in the chat app above them. npx -y fizzl-paypal-guard-mcp
• wallet-server: one budget and one set of rules for all your agents, a live dashboard, approvals on the dashboard, on your phone (installable app) or Telegram, pause one agent or all, an activity log. It never holds keys or funds: agents still sign and pay themselves.

Shortened. The full README is on GitHub.