# Provably-Fair Random Winner Picker

> Provably-Fair Random Winner Picker is a paid API for AI agents from pyfile-agent.taile3ff35.ts.net, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Selects a verifiably fair random winner from a comma-separated list of candidates using a seeded, auditable algorithm

## Facts

- Endpoint: GET https://pyfile-agent.taile3ff35.ts.net/data/fair/pick
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/provably-fair-random-winner-picker-9d296aa5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RW9UCeSSG5TpGpfSuH-DT

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 provably-fair-random-winner-picker-9d296aa5
```

Example prompt: Pick a provably fair winner from these candidates: Alice, Bob, Carol, Dave — use round 1, client seed 'myseed42', and nonce 1, so I can verify the result wasn't tampered with.

## When to prefer this

Choose this endpoint when you need auditable, tamper-evident random selection — e.g. giveaways, raffles, lotteries, or any scenario where participants must be able to independently verify the winner was chosen fairly. The commit-reveal scheme and client seed distinguish it from simple random number generators that offer no verifiability.

## Known failure modes

- Missing candidates parameter returns an error
- Empty or malformed candidate list fails validation
- Missing required parameters (round, client_seed, nonce) may produce an error or default behavior
- Payment failure (402) if x402 payment is not provided
- Network timeout if the Tailscale node is unreachable

## How this service works

Provably-fair winner selection from a comma-separated list. ?candidates=a,b,c&round=1&client_seed=s&nonce=1

## Output

Returns a JSON object containing the selected winner's name, their zero-based index in the candidate list, the total number of candidates, a unique round ID, a cryptographic commit hash, and a verification string that allows independent parties to confirm the result was not manipulated.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "commit": {
     "type": "string"
    },
    "verify": {
     "type": "string"
    },
    "winner": {
     "type": "string"
    },
    "round_id": {
     "type": "string"
    },
    "winner_index": {
     "type": "integer"
    },
    "candidates_count": {
     "type": "integer"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/provably-fair-random-winner-picker-9d296aa5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pyfile-agent.taile3ff35.ts.net](https://www.zero.xyz/host/pyfile-agent.taile3ff35.ts.net/llms.txt)