# Plainchain Fortune — Verifiable On-Chain Random Fortune

> Plainchain Fortune — Verifiable On-Chain Random Fortune is a paid API for AI agents from plainchain.appin60.com, paid per call via x402, $0.001042/call, status unknown (last checked 2026-10-14).

Returns a verifiably random fortune string selected by hashing the latest block on Base, providing tamper-resistant randomness anchored to blockchain state.

## Facts

- Endpoint: GET https://plainchain.appin60.com/v1/fortune?utm_source=zero.xyz
- Price: $0.001042/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/plainchain-fortune-verifiable-on-chain-random-fortune-b4049075
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iN8f8OI8bKVGREyvlck3D

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 plainchain-fortune-verifiable-on-chain-random-fortune-b4049075
```

Example prompt: Give me a random fortune that's verifiably picked from the latest Base block — I want the fortune text plus the block number and index so I can confirm how it was chosen.

## When to prefer this

Choose this endpoint when you need verifiable, tamper-resistant randomness anchored to a real blockchain block hash — not pseudo-random numbers from a software PRNG. It is ideal for agents that need an auditable random result (e.g. games, lotteries, or fair selection) on Base with a sub-cent pay-per-call cost and no API key required.

## Known failure modes

- Payment failure if USDC balance on Base is insufficient (x402 payment required)
- Network or RPC error retrieving the latest block from Base
- Stale or unavailable block data causing a timeout
- Invalid or malformed response if the upstream chain node is unreachable

## How this service works

Gas, balances, token data, address type, approvals, transaction decoding, x402 receipt verification and verifiable randomness on Base, Arbitrum, Ethereum and Optimism. No API key: pay $0.001-$0.01 per call in USDC on Base via x402.

## Output

Returns a JSON object containing: the fortune string, the total count of available fortunes, the Base block number used, the chain name, the index selected (blockHash mod count), and a plain-English description of how the index was picked (e.g. 'index = blockHash mod count').

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "required": {
   "type": "string"
  },
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "of": 32,
  "block": 36581662,
  "chain": "Base",
  "index": 19,
  "fortune": "Simulate first. Sign second.",
  "howPicked": "index = blockHash mod count"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/plainchain-fortune-verifiable-on-chain-random-fortune-b4049075/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from plainchain.appin60.com](https://www.zero.xyz/host/plainchain.appin60.com/llms.txt)