# 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, $0.03/call, status unknown (last checked 2026-11-01).

Checks x402 payment endpoints before you pay them and reads Base smart contract metadata (proxy, owner, privileged roles) directly from the chain.

## Facts

- Endpoint: POST https://minty-sprout.onrender.com/v1/extract?utm_source=zero.xyz
- Price: $0.03/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-61bbd961
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GuGOnDWgBZcKNXNFBbQ5B

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-61bbd961 -d '<json body>'
```

Example prompt: Before I pay that x402 endpoint at https://api.example.com/v1/data, can you run a preflight check on it and also pull the proxy and owner info for the Base contract at 0xAbC123...?

## When to prefer this

Use this endpoint when an AI agent needs to safely vet an x402 payment endpoint before sending funds, or when you need quick on-chain facts about a Base smart contract (owner, proxy, privileged roles) without setting up your own RPC connection. Prefer this over generic blockchain explorers when you want a single pay-per-call, agent-friendly API that combines x402 seller checks and Base contract introspection in one call.

## Known failure modes

- Invalid or unreachable x402 URL returns an error or empty seller info
- Contract address not found on Base returns no results
- Malformed input string causes a parsing error
- Rate limiting or server errors from the underlying render.com deployment
- Contract is not a proxy so proxy fields are null or absent

## 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 x402 seller metadata (whether the endpoint is a valid x402 seller, pricing, payment details) and/or Base contract facts (proxy implementation address, contract owner, privileged role addresses) read directly from the chain.

## 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-61bbd961/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)