# AISkills402 x402 Discovery Listing Review Skill File

> AISkills402 x402 Discovery Listing Review Skill File is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-23).

Delivers a paid SKILL.md file teaching AI agents how to work with x402 discovery catalogs, scanners, and buyers — purchased once via x402 micropayment in USDC on Base.

## Facts

- Endpoint: GET https://api.aiskills402.com/v1/skills/x402-discovery-listing-review/file?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aiskills402-x402-discovery-listing-review-skill-file-8788bae7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XI6NL_NvzQewutZcozbJZ

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-discovery-listing-review-skill-file-8788bae7
```

Example prompt: Buy me the x402 discovery listing review SKILL.md from AISkills402 — pay the $0.05 USDC fee over x402 and give me the file content and my redownload token so I can grab it again later.

## When to prefer this

Choose this endpoint when an AI agent needs a tested, versioned SKILL.md document specifically covering x402 discovery, listing review, catalogs, scanners, and buyer workflows — and you want a one-time purchase with permanent redownload rights. Prefer this over scraping documentation or prompting generically when you need a structured, curated skill file that has been validated for agent consumption and is deliverable via x402 micropayment.

## Known failure modes

- Payment not included or insufficient — 402 response with payment requirements returned
- Payment settled but not yet confirmed on-chain — receipt shows settled:false
- Invalid HTTP method used (non-GET/HEAD) — request rejected
- Network or API downtime — 5xx error with no file returned
- Redownload token expired or invalid when re-fetching — 401 or 404 response

## How this service works

x402 Listing Review: Catalogs, Scanners, Buyers — Reviews how a paid HTTP resource sold over x402 is advertised to catalogs, scanners and buyer agents, and how the seller's own scripts read those catalogs back, from pasted 402 bodies, OpenAPI documents, discovery files, liveness guard code, catalog presence check scripts and buyer alerts. Flags a tiered tariff advertised as one row (a comparison bot reads the structured amount, not the description), one liveness clock for several catalog rows t…

## Output

Returns a JSON object containing the full UTF-8 content of the SKILL.md file, the skill name and identifier, a SHA256 hash of the file for integrity verification, a version string, a settled on-chain receipt with the Base transaction hash, and a redownload URL and token for future free re-fetches without additional payment.

## 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"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "file": {
   "name": "SKILL.md",
   "content": "<the SKILL.md file>",
   "encoding": "utf-8"
  },
  "name": "x402 Listing Review: Catalogs, Scanners, Buyers",
  "skill": "x402-discovery-listing-review",
  "sha256": "<sha256 of SKILL.md>",
  "receipt": {
   "tx": "0x<settlement transaction>",
   "settled": true
  },
  "version": "1.0.0",
  "redownload": {
   "url": "<api>/v1/purchases/<token>",
   "token": "<64 hex chars>"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aiskills402-x402-discovery-listing-review-skill-file-8788bae7/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)