presign-guard wallet

presign-guard-wallet-mcp

A wallet with spending limits for AI agents, as an MCP server. Add it to Claude Desktop, Claude Code, Cursor or any other MCP client, and your agent can:

• pay for x402 APIs;
• send USDC.

It can only do that within the budget you set:

• You set the limits. For example: up to 5 USDC per payment and 20 USDC a day, and the agent is free to spend within them.
• Above a limit, you decide. You get a Telegram message with Approve / Deny, or the request shows up on your wallet server dashboard. No answer means no payment.
• Every signature is checked first by presign-guard. It checks for known drainers, sanctioned addresses and look-alike tokens. A red verdict is never signed.
• When in doubt, nothing is signed. If the check, Telegram or the server can't be reached, the wallet stops.

The key stays on your machine; the server only decides whether a signature is allowed. Each check costs $0.01, paid in USDC on Base from the same wallet, or from prepaid credits.

See the dashboard (demo data): https://wallet.fizzl.eu/demo

Tools

Set up

1. Make a separate wallet for the agent. Put only what it may spend in it: a few dollars of USDC on Base, plus a little ETH for gas if it will send transfers. Never use your main wallet.
2. Optional: phone approvals.
   • Create a bot with @BotFather, send it /start.
   • Get your chat id from @userinfobot.
3. Add it to your MCP client. For Claude Desktop, put this in claude_desktop_config.json:

{  "mcpServers": {    "wallet": {      "command": "npx",      "args": ["-y", "presign-guard-wallet-mcp"],      "env": {        "AGENT_KEY": "0x…the agent wallet's private key…",        "LIMIT_USDC_PER_TX": "5",        "LIMIT_USDC_PER_DAY": "20",        "TELEGRAM_BOT_TOKEN": "123456:ABC…",        "TELEGRAM_CHAT_ID": "123456789"      }    }  }}

For Claude Code:

claude mcp add wallet -e AGENT_KEY=0x… -e LIMIT_USDC_PER_TX=5 -e LIMIT_USDC_PER_DAY=20 -- npx -y presign-guard-wallet-mcp

Then ask your agent, for example: "Check my wallet, then get the BTC signal from https://ichimoku-signal.fizzl.eu/signal/BTC-USDT".

One budget for all your agents

Run the wallet server and make an agent key on its dashboard. It gives you:

• one price rule and one daily budget for all your agents;
• approvals on the dashboard and on Telegram;
• an activity log.

Then use these variables instead of LIMIT_* and TELEGRAM_*:

"env": {  "AGENT_KEY": "0x…",  "WALLET_SERVER_URL": "https://your-wallet-server.example",  "WALLET_SERVER_KEY": "awk_…"}

Configuration

One Telegram bot serves one running server at a time, and the bot must not have a webhook. To run several agents on one bot, use the wallet server.

Receipts

Every payment carries what it was for: the URL for pay_x402, and the agent's reason if it gives one. With a wallet server, that shows on the receipt for each payment, together with:

• the amount and recipient;
• presign-guard's signed verdict;
• the approval;
• the x402 settlement;
• what the agent got back: the API's answer (up to 16,000 characters), shown in plain form on the receipt.

Telegram approval requests say what the payment is for too. See a receipt in the demo: click a purchase under "Purchases".

When something is refused

The tool returns an error the agent can read and pass on to you. Examples:

• Not done (over_limit): 8 USDC is over the limit of 5 per transaction (denied by the owner);
• Not done (red): not signed: red (known_drainer).

Also available

• presign-guard-wallet: the same guard for your own viem code.
• presign-guard-agentkit: for Coinbase AgentKit agents.

License

MIT