> ## Documentation Index
> Fetch the complete documentation index at: https://xavierscript.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# x402 Payment

> Guided x402 payment flow with cost confirmation prompt

The `x402_payment` prompt guides an AI agent through the complete x402 payment lifecycle — from cost discovery to payment execution to data retrieval.

## When It's Used

Invoked when an agent needs to purchase data from an x402-gated endpoint and wants structured guidance through the payment flow.

## What the Agent Does

1. **Probes** the target URL using `probe_x402` to discover:
   * Price (USDC amount)
   * Merchant address
   * Payment token mint
2. **Evaluates** whether the cost is acceptable:
   * Checks wallet balance (sufficient USDC?)
   * Validates against spending policy
   * Confirms the merchant address is reasonable
3. **Confirms** the payment details to the user (if in interactive mode)
4. **Executes** payment using `pay_x402_invoice`
5. **Returns** the purchased data along with the transaction signature and Explorer link

## Benefits

* **Cost transparency:** The agent always shows the price before paying
* **Policy compliance:** Spending limits are checked before the transaction
* **Structured flow:** Ensures the agent follows the probe → evaluate → pay → return pattern consistently