# Bill Spike Finder

> Bill Spike Finder is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-11).

Analyzes web app code and config to identify loops, retries, and patterns that cause unexpected billing spikes on Vercel, Turso, Cloudflare Workers/D1, and paid AI APIs

## Facts

- Endpoint: GET https://api.aiskills402.com/v1/skills/bill-spike-finder/file?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bill-spike-finder-7715a449
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wW_9C187ffwSAj4sfp8sF

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 bill-spike-finder-7715a449
```

Example prompt: My Vercel and Cloudflare Workers bills spiked out of nowhere this month — can you analyze my app's code and config to find any loops, duplicate schedulers, uncapped retries, or self-triggering jobs that might be running up the bill?

## When to prefer this

Choose this endpoint when you need structured, expert-curated guidance on diagnosing unexpected bill spikes on modern serverless and edge infrastructure (Vercel, Cloudflare Workers/D1, Turso) or paid AI APIs, and you want a reusable skill document (SKILL.md) that an AI agent can apply repeatedly. Prefer this over generic code review tools when the specific concern is cost runaway due to loops, retries, polling, or self-triggering patterns rather than correctness or security bugs.

## Known failure modes

- Payment not settled — x402 payment must complete before skill file is returned
- Invalid or missing input headers — request may be rejected with 4xx
- Network timeout if the skill delivery service is temporarily unavailable
- SHA256 mismatch if file integrity cannot be verified on the client side
- Redownload token expiry if the token is used after its validity window

## How this service works

Bill Spike Finder: Finds the loops behind a bill spike or an unexpected bill. Reviews a web app's code and config for loops and repeats that run up the bill on their own on Vercel, Turso, Cloudflare Workers and D1 and paid AI APIs. Finds two schedulers on one job, retries without a cap, work that triggers itself, client polling and React render loops, caches cleared on every write, middleware running on every static file, queues that resend failures forever, image settings that multiply transfo…

## Output

Returns a SKILL.md file containing a detailed skill document describing how to identify bill-spike-causing patterns, along with metadata including the skill name, version, SHA256 hash for integrity verification, a payment receipt with settlement transaction hash, and a redownload URL and token for retrieving the file again without paying again.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "file": {
   "name": "SKILL.md",
   "content": "<the SKILL.md file>",
   "encoding": "utf-8"
  },
  "name": "Bill Spike Finder",
  "skill": "bill-spike-finder",
  "sha256": "<sha256 of SKILL.md>",
  "receipt": {
   "tx": "0x<settlement transaction>",
   "settled": true
  },
  "version": "1.0.0",
  "redownload": {
   "url": "<api>/v1/purchases/<token>",
   "token": "<64 hex chars>"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bill-spike-finder-7715a449/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.aiskills402.com](https://www.zero.xyz/host/api.aiskills402.com/llms.txt)