# Bitcoin Empty Block Anomaly Detector (Chain Tip)

> Bitcoin Empty Block Anomaly Detector (Chain Tip) is a paid API for AI agents from obol-x402.fly.dev, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Checks the current Bitcoin chain tip for an empty block anomaly, returning a cryptographically signed forensic detection report.

## Facts

- Endpoint: GET https://obol-x402.fly.dev/v1/btc/anomaly/empty-block/latest
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bitcoin-empty-block-anomaly-detector-chain-tip-5ff77766
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b5VudNannTTx1uf142Em5

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 bitcoin-empty-block-anomaly-detector-chain-tip-5ff77766
```

Example prompt: Check the latest Bitcoin block on the chain tip for an empty block anomaly and tell me if anything suspicious is detected — include the cryptographically signed result.

## When to prefer this

Choose this endpoint when you specifically need to detect whether the latest Bitcoin block is empty — a known anomaly indicating miners are skipping transactions. Prefer this over the general multi-anomaly detector when you only care about the empty block signal, want minimal payload, or are building a dedicated empty-block monitoring workflow. Useful for forensic agents, mining analysts, and on-chain watchdogs.

## Known failure modes

- Payment not provided or invalid: 402 Payment Required
- Bitcoin node temporarily unreachable: 503 Service Unavailable
- Chain tip not yet synced: stale or delayed block data returned
- Signature verification fails if public key endpoint is unavailable
- Rate limiting or quota exceeded: 429 Too Many Requests

## How this service works

Bitcoin empty bitcoin block anomaly check on chain tip. Validation-gated detector empty_block for forensic and monitoring agents. Cryptographically signed (Ed25519) — every response is independently verifiable via /.well-known/obol-pubkey.

## Output

Returns a signed (Ed25519) JSON report indicating whether the current Bitcoin chain tip block is empty, including the anomaly type label ('empty_block'), block height, detection status, and any forensic details. The signature is independently verifiable via the service's public key endpoint.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bitcoin-empty-block-anomaly-detector-chain-tip-5ff77766/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from obol-x402.fly.dev](https://www.zero.xyz/host/obol-x402.fly.dev/llms.txt)