# OceanEye Sentinel 2.0 — Polymarket Basket Arbitrage Verifier

> OceanEye Sentinel 2.0 — Polymarket Basket Arbitrage Verifier is a paid API for AI agents from sentinel.oceaneye-ai.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-04).

Verifies pricing integrity of a Polymarket prediction market basket, detecting Dutch book arbitrage edges and computing atomic cost/payout figures

## Facts

- Endpoint: POST https://sentinel.oceaneye-ai.com/x402/verify-polymarket-basket?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/oceaneye-sentinel-2-0-polymarket-basket-arbitrage-verifier-dace9a1a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-4uy0BxwV-1b7J2x40wzo

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 oceaneye-sentinel-2-0-polymarket-basket-arbitrage-verifier-dace9a1a -d '<json body>'
```

Example prompt: Check whether these Polymarket basket ask prices [0.52, 0.31, 0.19] leave any Dutch book arbitrage edge, using a 10 bps fee and $10,000 payout per share — tell me the total basket cost in atomic units and whether the prices are verified.

## When to prefer this

Use this endpoint when you need a fast, paid, cryptographically-auditable check of Polymarket basket pricing for Dutch book or arbitrage conditions, particularly when you need atomic-unit cost/payout figures and a boolean verified signal in a single call. Prefer it over manual price-summing when you need reliable computation with fee adjustments and optional custom conversion formulas.

## Known failure modes

- Invalid or missing outcome_ask_prices array returns a validation error
- Prices that do not sum to a valid probability distribution may cause unexpected edge values
- Malformed custom_conversion_formula string may result in a computation error
- Network or payment failure (x402 protocol) prevents the call from completing
- Extreme price values (negative or above 1.0) may cause out-of-range results

## How this service works

OceanEye Sentinel 2.0 — Plataforma de Inteligencia Marítima Satelital con Radar SAR Sentinel-1, Segmentación SAM 3.1 (Puerta A + Control Negativo), Arena Multimodal Muse Wonder 1.0 vs Muse Spark 1.3 (n=30) y Cadena de Custodia Ed25519.

## Output

Returns a JSON object with: a boolean indicating whether the basket pricing is verified (no-arbitrage), the computed arbitrage edge in atomic units, the payout per share in atomic units, a boolean flag for whether a Dutch book edge was detected, and the total basket cost in atomic units.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "fee_bps": {
   "type": "integer",
   "default": 0
  },
  "payout_per_share": {
   "type": "number",
   "default": 10000
  },
  "outcome_ask_prices": {
   "type": "array",
   "items": {
    "type": "number"
   },
   "description": "List of best ask prices across all basket outcomes"
  },
  "custom_conversion_formula": {
   "type": [
    "string",
    "null"
   ]
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "verified": {
   "type": "boolean"
  },
  "arbitrage_edge_atomic": {
   "type": "integer"
  },
  "payout_per_share_atomic": {
   "type": "integer"
  },
  "dutch_book_edge_detected": {
   "type": "boolean"
  },
  "total_basket_cost_atomic": {
   "type": "integer"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/oceaneye-sentinel-2-0-polymarket-basket-arbitrage-verifier-dace9a1a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sentinel.oceaneye-ai.com](https://www.zero.xyz/host/sentinel.oceaneye-ai.com/llms.txt)