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Fund your AI agent

Verified September 19, 2026 against the live Zambo Day Pass challenge and the linked provider documentation.

Your agent needs a wallet that can hold and sign transactions with USDC on Base. The wallet address that receives the stipend is the address that should be able to sign the x402 EIP-3009 authorization.

1. Get USDC on Base

Exchange withdrawal

If your exchange supports native USDC withdrawals on Base, follow that exchange’s current withdrawal instructions and select Base as the network. Confirm the destination network and asset on the withdrawal screen before sending; exchange support pages and network availability can change.

Bridge from another network

If the USDC is already on another network, use the current routes listed in Base’s ecosystem bridge guide. The guide distinguishes direct Coinbase withdrawals from bridge routes. Follow the selected bridge’s live confirmation, fee, and destination-network screens rather than relying on a fixed timing or fee estimate.

Before sending: verify that the destination is the agent wallet address and that the received asset is native USDC on Base. A balance on another chain is not the same as Base USDC.

2. Choose a wallet setup

Ampersend

Ampersend’s current setup is documented in its Create an Agent guide: choose Add an Agent, enter the agent name, optionally enable spending configuration, and create it. The documented result is a smart-account wallet with a unique agent address. Use the linked agent configuration guide for the current spending controls; do not assume a limit or permission default.

Arc Portal

Arc currently documents a Portal model that supports creating or connecting a wallet, funding it through the available onramp, and enabling agents with limits and permissions. The Portal product flow includes monitoring balances and activity and managing agent wallets. Configure the wallet permissions deliberately: the agent may transact within the limits you set, and you remain responsible for monitoring activity.

3. Use a stipend, not an open-ended wallet

The practical model is simple: a human funds the agent wallet once with a defined USDC budget, then configures the agent’s spending limits and permissions. The agent spends only within that approved budget. Start with the amount needed for the task, review activity, and add more only when the next task requires it.

4. Buy the Zambo Day Pass from the agent

The agent-native flow is a live challenge followed by a signed payment retry:

  1. GET https://zambo.dev/api/x402/day-pass returns the current x402 v2 requirements.
  2. Sign the returned EIP-3009 TransferWithAuthorization payload with the funded Base wallet.
  3. Retry with the base64 JSON payment envelope in the X-Payment header.
  4. A successful response includes the settlement transaction and verifiable receipt data. Use the returned access key on subsequent MCP requests until its expiry.
{
  "x402Version": 2,
  "network": "eip155:8453",
  "asset": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
  "amount": "1490000",
  "payTo": "0xb753be5Eac5B29c711051DfF91279834e9C9b9AC"
}

This is one payment for 24-hour listed access, not a per-call charge. The human checkout is available at zambo.dev/day-pass.

Payment details are always taken from the live 402 response. If the amount, asset, network, or recipient changes, stop and request a fresh challenge instead of reusing this example.