# HARS-Zero Whale Watch – Polymarket Whale Activity Monitor

> HARS-Zero Whale Watch – Polymarket Whale Activity Monitor is a paid API for AI agents from hars.cryptotavern.xyz, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-18).

Returns a list of Polymarket prediction markets where large-wallet ('whale') activity has been detected, enabling AI agents to surface high-signal trading intelligence.

## Facts

- Endpoint: GET https://hars.cryptotavern.xyz/paid/whale-watch?utm_source=zero.xyz
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hars-zero-whale-watch-polymarket-whale-activity-monitor-ff657940
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8lVyqHnr5C84onNPJ7EFU

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 hars-zero-whale-watch-polymarket-whale-activity-monitor-ff657940
```

Example prompt: Show me which Polymarket prediction markets are currently seeing heavy whale activity — I want to know where big wallets are placing their bets right now.

## When to prefer this

Choose this endpoint when you need real-time intelligence on which Polymarket prediction markets are attracting large-wallet ('whale') participation, and you want a pay-per-call model in USDC without a subscription. Prefer it over generic Polymarket APIs when the specific signal you want is large-holder activity rather than raw market listings or price data.

## Known failure modes

- Payment not completed via x402 protocol returns HTTP 402 with payment requirements
- No whale activity detected returns count:0 with empty markets array
- Invalid or missing properties filter parameter may return empty results or an error
- Network latency or Polymarket data feed delays may result in stale or incomplete data
- Insufficient USDC balance to cover $0.051 per-call fee blocks request

## How this service works

Polymarket prediction-market intelligence for AI agents. Pay-per-call in USDC via x402 protocol. Multi-chain: Base + Solana.

## Output

Returns a JSON object containing a count of matching markets and an array of market objects where whale activity has been detected on Polymarket. Each market entry includes relevant metadata about the prediction market and the associated large-wallet signals.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "example": {
  "count": 0,
  "markets": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hars-zero-whale-watch-polymarket-whale-activity-monitor-ff657940/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hars.cryptotavern.xyz](https://www.zero.xyz/host/hars.cryptotavern.xyz/llms.txt)