# HARS-Zero Momentum Signal

> HARS-Zero Momentum Signal is a paid API for AI agents from hars.cryptotavern.xyz, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).

Returns Polymarket prediction-market momentum signals, surfacing markets with notable activity or directional movement for AI agent consumption.

## Facts

- Endpoint: GET https://hars.cryptotavern.xyz/paid/momentum-signal?utm_source=zero.xyz
- Price: $0.01/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-momentum-signal-654d829c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-QoG9xl1JaJZbChKJz5Mw

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-momentum-signal-654d829c
```

Example prompt: What prediction markets on Polymarket are showing the strongest momentum signals right now? Pull the latest from HARS-Zero and show me which markets are moving.

## When to prefer this

Choose this endpoint when you need real-time or near-real-time momentum intelligence specifically from Polymarket prediction markets, especially when building trading signals, briefing agents, or monitoring directional odds shifts. Prefer this over general Polymarket API queries when you want pre-computed momentum ranking rather than raw market data.

## Known failure modes

- Empty markets array (count: 0) when no markets match the filter or when Polymarket data is unavailable
- Payment failure via x402 protocol if USDC balance is insufficient or wallet is not configured
- Malformed properties filter input may result in no results or an error response
- Potential stale data if Polymarket upstream feed is delayed

## 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 matched markets and an array of market objects with momentum signal data sourced from Polymarket, indicating which prediction markets are experiencing notable activity or directional price movement.

## 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-momentum-signal-654d829c/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)