# VexQuill Contract Audit API

> VexQuill Contract Audit API is a paid API for AI agents from x402-audit-api.vexquill.deno.net, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-23).

Performs automated static security analysis of a Solidity smart contract on Base by contract address, returning findings and a risk score.

## Facts

- Endpoint: GET https://x402-audit-api.vexquill.deno.net/scan?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vexquill-contract-audit-api-e294b479
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Qic_UriQ71ccgyFM4NK4Q

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 vexquill-contract-audit-api-e294b479
```

Example prompt: Can you run a security audit on the Base smart contract at 0x1234567890abcdef1234567890abcdef12345678 and tell me if there are any vulnerabilities or what its risk score is?

## When to prefer this

Choose this endpoint when you need a quick, no-signup, pay-per-use static security audit of a Solidity contract deployed on Base with verified source on Sourcify. Ideal for agents that need on-demand contract risk scoring without managing API keys or subscriptions. Best for single-contract lookups rather than bulk audits.

## Known failure modes

- Contract address not found or not verified on Sourcify — audit cannot proceed without verified source code
- Invalid or malformed address format — must be a valid 0x-prefixed Ethereum/Base address
- Payment failure via x402 — audit not performed if USDC payment on Base does not go through
- Contract on a network other than Base — only Base-deployed contracts with Sourcify verification are supported
- Service downtime or Deno hosting errors — may return 5xx errors

## How this service works

Automated static security analysis of Solidity smart contracts. Pay $0.005 USDC on Base per audit via x402. No signup, no API key.

## Output

Returns a JSON object containing the target contract address, an array of security findings (each describing a potential vulnerability), a risk score (numeric), and the timestamp of the audit. The findings array details any detected issues such as reentrancy, integer overflows, or access control problems.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "address"
 ],
 "properties": {
  "address": {
   "type": "string",
   "description": "Base contract address (0x...) with verified source on Sourcify."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "target": {
   "type": "string"
  },
  "findings": {
   "type": "array",
   "items": {
    "type": "object"
   }
  },
  "auditedAt": {
   "type": "string"
  },
  "riskScore": {
   "type": "number"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vexquill-contract-audit-api-e294b479/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-audit-api.vexquill.deno.net](https://www.zero.xyz/host/x402-audit-api.vexquill.deno.net/llms.txt)