# Foundry: x402 Preflight and Base Contract Facts

> Foundry: x402 Preflight and Base Contract Facts is a paid API for AI agents from minty-sprout.onrender.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-11-01).

Checks x402 payment endpoints for trustworthiness before paying them, and reads proxy, owner, and privileged role data from Base smart contracts on-chain.

## Facts

- Endpoint: POST https://minty-sprout.onrender.com/v1/injection-screen?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/foundry-x402-preflight-and-base-contract-facts-41ce5d11
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1VCazgYNlaLdI3G9QDjsm

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 foundry-x402-preflight-and-base-contract-facts-41ce5d11 -d '<json body>'
```

Example prompt: Before I pay this x402 endpoint at https://some-seller.example.com/data, screen it for me — check if it's trustworthy and also tell me who owns the Base contract at 0xAbCd1234... including its proxy and any privileged roles.

## When to prefer this

Use this endpoint when an AI agent needs to vet an x402 payment seller before committing funds, or when it needs to quickly audit a Base smart contract's control structure (proxy, owner, privileged roles) without writing custom RPC calls. Prefer this over raw RPC lookups when you want a single, pre-parsed response covering both x402 trust signals and on-chain contract facts in one call.

## Known failure modes

- Invalid or unreachable x402 URL returns an error or empty trust signals
- Non-existent or non-contract Base address returns no contract data
- Malformed input string causes a 400-level error
- Rate limiting or server unavailability on the Render-hosted service returns 5xx
- Contract with no proxy or ownership pattern returns null for those fields

## How this service works

Pay-per-call data for agents: check x402 sellers before paying them, and read Base contracts' proxy, owner and privileged powers straight from the chain.

## Output

Returns trust signals and metadata about an x402 payment endpoint (such as domain age, suspicious patterns, and payment history signals) and/or on-chain facts about a Base contract including its proxy implementation address, owner address, and any privileged or admin roles assigned to specific addresses.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "string",
   "maxLength": 8000
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/foundry-x402-preflight-and-base-contract-facts-41ce5d11/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from minty-sprout.onrender.com](https://www.zero.xyz/host/minty-sprout.onrender.com/llms.txt)