# AISkills402 — A2A Agent Card SKILL.md Download

> AISkills402 — A2A Agent Card SKILL.md Download is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-27).

Downloads the A2A 1.0 Agent Card Writer SKILL.md file via x402 micropayment, granting permanent ownership with free re-downloads

## Facts

- Endpoint: GET https://api.aiskills402.com/v1/skills/a2a-agent-card/file?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aiskills402-a2a-agent-card-skill-md-download-c7d3eb71
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lTkqqFjqhDJcLsIdQR6hy

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-a2a-agent-card-skill-md-download-c7d3eb71
```

Example prompt: Buy me the A2A Agent Card Writer skill from AISkills402 — pay the $0.03 USDC fee and download the SKILL.md file so I can keep it and re-download it anytime.

## When to prefer this

Choose this endpoint when an AI agent needs a tested, ready-to-use SKILL.md definition specifically for writing A2A 1.0 agent cards, and wants a permanent one-time purchase with redownload rights rather than a recurring subscription. Ideal for agents that support x402 micropayments in USDC on Base and need to build out their skill library without managing complex licensing.

## Known failure modes

- Payment not included or insufficient — x402 payment required error with expected amount and asset
- Payment fails to settle on-chain — receipt returned with settled: false
- Incorrect HTTP method — only GET and HEAD are accepted
- Skill file temporarily unavailable — server error response
- Invalid or expired payment header — authentication/authorization failure

## How this service works

A2A 1.0 Agent Card Writer — Writes the JSON an agent needs for version 1.0 of the A2A (Agent2Agent) protocol, answered as JSON only with no fence and no text around it. Covers the agent card (supportedInterfaces with protocolBinding and protocolVersion, capabilities, skills, securitySchemes and securityRequirements, default input and output modes), the JSON-RPC requests (SendMessage, SendStreamingMessage, GetTask, ListTasks, CancelTask, push notification configs), the replies (task, message, da…

## Output

Returns a JSON object containing the SKILL.md file name and UTF-8 content, the skill's canonical identifier ('a2a-agent-card'), its human-readable name ('A2A 1.0 Agent Card Writer'), a SHA256 hash for integrity verification, the version string, an on-chain settlement transaction hash with confirmation status, and a redownload URL plus token for future free access.

## 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": "A2A 1.0 Agent Card Writer",
  "skill": "a2a-agent-card",
  "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-a2a-agent-card-skill-md-download-c7d3eb71/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)