# aiskills402 x402 Buyer Payment Decision Skill

> aiskills402 x402 Buyer Payment Decision Skill is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-01).

Downloads a SKILL.md decision-rule file that tells an AI agent holding a wallet when to SIGN, REFUSE, or escalate to a human before making an x402 HTTP payment, and how to verify delivery and avoid double-paying.

## Facts

- Endpoint: GET https://api.aiskills402.com/v1/skills/x402-buyer/file?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aiskills402-x402-buyer-payment-decision-skill-4be510c6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mvYsE9IeQKKy4b-EHJDu4

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability aiskills402-x402-buyer-payment-decision-skill-4be510c6
```

Example prompt: Before I let you pay for that x402 resource, download the x402 buyer decision rules so you can check whether you should sign, refuse, or ask me first — and how to confirm delivery without paying twice.

## When to prefer this

Use this endpoint specifically when an AI agent operates with an x402-compatible wallet and needs structured, actionable decision rules for handling HTTP 402 payment challenges. Prefer this over ad-hoc prompting or general payment guides when you need agent-ready SKILL.md format rules that cover the full SIGN/REFUSE/ASK decision tree and retry safety logic. Especially valuable for agents that may encounter unfamiliar sellers or failed paid requests.

## Known failure modes

- Payment of $0.03 USDC not completed — returns 402 with payment details rather than the skill file
- Network timeout — agent should retry with HEAD first to check idempotency
- Malformed input schema (missing required 'type' or 'method' fields) — returns 400 validation error
- x402 facilitator unavailable — payment cannot be processed, request fails
- Duplicate payment risk if agent retries without checking delivery — covered by the skill file itself once downloaded

## How this service works

Pay Safely over x402: Decision rules for an AI agent that holds a wallet and receives an HTTP 402 payment request (x402 v2). Decides SIGN, REFUSE or ASK the human before any money moves, and says how to verify the delivery and retry without paying twice. Use when an agent is about to pay over x402, gets a 402 response, must check a seller's payment terms, or a paid request failed and it is unsure whether to pay again. One-time purchase of the SKILL.md file (Agent Skills format), $0.03 USDC, you…

## Output

A SKILL.md file (Agent Skills format) containing structured decision rules for x402 payment scenarios: conditions under which the agent should SIGN (proceed with payment), REFUSE (reject the payment request), or ASK the human for authorization; instructions for verifying that paid content was actually delivered; and guidance on safe retry logic to avoid duplicate payments.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aiskills402-x402-buyer-payment-decision-skill-4be510c6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.aiskills402.com](https://www.zero.xyz/host/api.aiskills402.com/llms.txt)