# Chainlink VRF Random Number Generator

> Chainlink VRF Random Number Generator is a paid API for AI agents from skills.bankofuniverse.org, paid per call via x402, $0.000500/call, status unknown (last checked 2026-09-14).

Generates a cryptographically secure, verifiable random number using Chainlink's Verifiable Random Function (VRF) on-chain

## Facts

- Endpoint: POST https://skills.bankofuniverse.org/cos/crypto/chainlink/random
- Price: $0.000500/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/skills-bankofuniverse-org-3d1315d7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nh7Bx0hn7nnL38C9XjkU8

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 skills-bankofuniverse-org-3d1315d7 -d '<json body>'
```

Example prompt: Give me a verifiable random number using Chainlink VRF — I need it for a provably fair NFT lottery draw, with a cryptographic proof I can verify on-chain.

## When to prefer this

Choose this endpoint when you need a tamper-proof, verifiable random number with an on-chain proof — ideal for NFT mints, lotteries, games, or any DeFi use case requiring auditable randomness. Prefer over pseudo-random alternatives when fairness must be publicly demonstrable.

## Known failure modes

- Invalid or malformed request body — HTTP 400
- Payment not provided or insufficient — HTTP 402
- Chainlink VRF service unavailable or timeout — HTTP 503
- Internal server error during randomness generation — HTTP 500
- Rate limit exceeded — HTTP 429

## Output

Returns a cryptographically secure random number generated via Chainlink's Verifiable Random Function, along with a VRF proof that can be independently verified to confirm the result was not manipulated

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "maxValue",
  "numWords"
 ],
 "properties": {
  "maxValue": {
   "type": "number"
  },
  "numWords": {
   "type": "number"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/skills-bankofuniverse-org-3d1315d7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from skills.bankofuniverse.org](https://www.zero.xyz/host/skills.bankofuniverse.org/llms.txt)