# x402 Trust Semantic Search

> x402 Trust Semantic Search is a paid API for AI agents from x402-trust.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Searches the x402 Trust index for x402 payment endpoints matching a natural-language query, returning ranked results with trust grades and scores

## Facts

- Endpoint: POST https://x402-trust.com/v1/semantic-search
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-trust-semantic-search-3b364249
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_df0HLbOsyfihLztsL-UHf

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 x402-trust-semantic-search-3b364249 -d '<json body>'
```

Example prompt: Search x402 Trust for the top 5 x402 endpoints related to real-time stock prices, and show me their trust grades and per-call costs.

## When to prefer this

Use this endpoint when an AI agent needs to discover x402-compatible payment endpoints by semantic description rather than exact URL — especially when comparing options by trust grade, uptime reliability, or price before committing to a paid API call. Prefer over manual browsing or raw x402scan listings when trust ranking and semantic similarity are needed together.

## Known failure modes

- Query too vague returns low-similarity, unrelated endpoints
- Endpoints in index may not yet have trust scores (grade and score return null)
- Limit parameter ignored or capped at server maximum
- Price data absent for newly listed or unmonitored endpoints
- Service returns empty matches array if no endpoints match the query
- Malformed request body returns 4xx error

## How this service works

Trust, reputation & reliability scores for x402 endpoints. We monitor every listed x402 service 24/7: uptime probes, 402-envelope compliance, price history, and real on-chain USDC settlement volume. Free grade & recommendation for any endpoint, $0.005 for a full data breakdown.

## Output

Returns a ranked list of up to `limit` x402 endpoint matches, each containing: a numeric endpoint ID, letter-grade trust rating (A–F or null if unscored), numeric trust score (0–100 or null), the resource URL, price in USD (or null), cosine similarity to the query, a short description, a link to the full endpoint page on x402-trust.com, and a priceCeiling flag. Also includes total match count, the original query, and a generation timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "integer"
  },
  "query": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "note": "Ranked by cosine similarity, with trust score as a tiebreaker. score/grade are null when the endpoint is not yet scored. No verdict or flag detail here: POST /v1/x402-trust carries those.",
  "count": 2,
  "query": "weather forecast",
  "matches": [
   {
    "id": 12345,
    "grade": "A",
    "score": 88.1,
    "resource": "https://api.weather.example/v1/forecast",
    "amountUsd": 0.002,
    "similarity": 0.912,
    "description": "Hyperlocal weather forecasts, priced per call.",
    "endpointPage": "https://x402-trust.com/endpoint/12345",
    "priceCeiling": false
   },
   {
    "id": 12399,
    "grade": null,
    "score": null,
    "resource": "https://wx.example.net/api/now",
    "amountUsd": null,
    "similarity": 0.874,
    "description": null,
    "endpointPage": "https://x402-trust.com/endpoint/12399",
    "priceCeiling": false
   }
  ],
  "generatedAt": 1782826208450
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-trust-semantic-search-3b364249/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-trust.com](https://www.zero.xyz/host/x402-trust.com/llms.txt)