PayPal, guarded

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@0.20.0
• 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.

See the dashboard live (demo, example data) →

Agent skills that teach Claude Code, Codex, Cursor and other agents to use the wallet and the Fizzl checks: Fizzl13/fizzl-skills.

import { guardWallet } from "presign-guard-wallet";

const wallet = guardWallet(walletClient, {
  pay, // a fetch that pays x402, or creditKey for prepaid presign-guard checks
  server: { url: process.env.WALLET_SERVER_URL, key: process.env.WALLET_SERVER_KEY },
});
// Under your price: signs. Above it: you get a request on the dashboard and on Telegram.
// Red verdict: never signed. Server unreachable: stops instead of signing.

Try it from your phone: Actions → telegram-demo → Run workflow (a pretend agent, a stub wallet, no money moves).

Research: do AI agents pay safely?

• agent-safety-bench: an open benchmark of how an AI agent with a wallet handles x402 payments. It checks whether the agent pays honest sellers and refuses the traps: an overcharge, a sanctioned payee, a price over budget, the expensive one of two options, an instruction injected into an API's answer, and a seller that takes the money and asks again. Everything runs offline against simulated sellers with the official x402 client, and nothing is ever paid. It compares agents with and without x402 Doctor's preflight skill.

Paid-API examples

Small, open examples of AI agents combining paid APIs with x402: each call is paid per request in USDC, with no accounts or API keys.

Example	What it does	Services	Cost per run
wallet-mcp	MCP server presign-guard-wallet-mcp: wallet tools for any MCP client (pay x402 APIs, send USDC), every signature checked by presign-guard and kept to spending limits, Telegram or wallet-server approval above them	presign-guard	$0.01 per checked signature (or prepaid credits)
fizzl-py	PyPI package fizzl: the four checks for Python agents (requests + x402), plus LangChain tools	presign-guard, x402 Doctor	$0.001 to $0.02 per check (or prepaid credits)
fizzl-langchain	npm package fizzl-langchain: the five checks as LangChain.js tools, for LangChain and LangGraph agents	presign-guard, x402 Doctor	$0.001 to $0.02 per check (or prepaid credits)
ai-sdk-guard	npm package presign-guard-ai-sdk: four Vercel AI SDK tools (check before signing, token check, wallet approvals, endpoint preflight)	presign-guard, x402 Doctor	$0.001 to $0.02 per check (or prepaid credits)
agentkit-guard	npm package presign-guard-agentkit: wraps a Coinbase AgentKit wallet provider so every spending action is checked by presign-guard and kept to spending limits, with Telegram or wallet-server approval above them	presign-guard	$0.01 per checked signature (or prepaid credits)
solana-agent-kit-guard	npm package presign-guard-solana-agent-kit: wraps a Solana Agent Kit wallet so every transaction is checked by presign-guard (decoded and simulated) and kept to SOL and USDC limits, with Telegram or wallet-server approval above them	presign-guard	$0.01 per checked transaction (or prepaid credits)
paypal-guard	npm package fizzl-paypal-guard: limits, checks and Telegram approval between an AI agent and PayPal's Agent Toolkit (refunds, disputes, cancellations, invoices)	PayPal (read-only lookups), TypeSafe Jev (optional)	free
paypal-guard-mcp	MCP server fizzl-paypal-guard-mcp: PayPal's Agent Toolkit for any MCP client, every call that moves money checked by fizzl-paypal-guard, approval on Telegram, the Fizzl wallet or in the chat app above the limits	PayPal (your own REST app)	free
guard-wallet	npm package presign-guard-wallet: a viem wallet that asks presign-guard before every signature, keeps to spending limits and asks you on Telegram above them	presign-guard	$0.01 per checked signature (or prepaid credits)
crowding-check	Perp funding + CFTC leveraged-fund positioning + the Ichimoku cloud on 4h and 1d, combined into a short read ("crowded long + below the cloud = caution")	Edge Agents, Ichimoku Signal	$0.32
p0-guard	Project 0 builds an unsigned Solana transaction (deposit, borrow, loop and more), presign-guard checks every step (decoded, simulated, accounts screened), and the agent's wallet signs and sends only on green (--send)	Project 0, presign-guard	$0.01 per checked step
token-check	Before buying, holding or accepting a token: a verdict (go / ask / stop) with reasons and market data, Solana and EVM tokens; pays on Solana or Base	presign-guard	$0.01
payer-screen	npm package presign-guard-payer-screen: for sellers. Express middleware that screens who pays your x402 API against the OFAC SDN list before the payment settles (EVM, Solana, Algorand, XRP Ledger); a listed payer gets 451 and is never charged	presign-guard open list (free)	free
safe-fetch	npm package x402-safe-fetch: the safe-pay logic as a drop-in fetch for your own agent (preflight, go / caution / no_go, budget cap, trusted hosts, 10-minute verdict cache)	x402 Doctor + the endpoint	$0.001 + the endpoint
safe-pay	Before paying an x402 endpoint it has never used, the agent pays $0.001 for a preflight and pays only on go, within a budget	x402 Doctor + the endpoint	$0.001 + the endpoint

Each example has a --dry-run that shows the prices without paying. Use a dedicated wallet with a little USDC, keep its key in your environment, and never commit it.

Check your own x402 endpoint for free with x402 Doctor.

These are examples of combining services, not trade advice.

License

MIT (see LICENSE), except wallet-server/, which is AGPL-3.0-only (see wallet-server/LICENSE). The packages you install in your own agent (guard-wallet, wallet-mcp, safe-fetch, the framework guards and the rest) are MIT.