# Base Proxy Detection (agentshelf.syntexa.ch)

> Base Proxy Detection (agentshelf.syntexa.ch) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-18).

Detects whether a Base mainnet address is an upgradeable proxy and returns its implementation, admin, and proxy kind (EIP-1967, UUPS, Transparent, or legacy OpenZeppelin).

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/base-proxy?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-proxy-detection-agentshelf-syntexa-ch-90d41e9e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__Y-6M4MglMd8xC2CT45pR

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 base-proxy-detection-agentshelf-syntexa-ch-90d41e9e -d '<json body>'
```

Example prompt: Can you check if the contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base is an upgradeable proxy, and if so, what kind and what's the implementation address?

## When to prefer this

Use this endpoint when you need to determine proxy status and implementation details for a contract specifically on Base mainnet, and need support for legacy OpenZeppelin slots (including USDC-style proxies) in addition to modern EIP-1967, UUPS, and Transparent patterns. Prefer this over generic Ethereum proxy checkers when Base mainnet is the target chain.

## Known failure modes

- Invalid or malformed address returns a validation error
- Non-existent or EOA address returns upgradeable_proxy: false with null fields
- RPC connectivity issues with Base mainnet may cause timeouts
- Exotic or custom proxy patterns not matching known slots may not be detected
- Payment not included or insufficient USDC causes 402 Payment Required

## How this service works

Call when an agent needs whether a Base address is an upgradeable proxy, plus implementation and admin. Detects EIP-1967, UUPS, Transparent, and legacy OpenZeppelin slots, including USDC. Read-only. No spend. Send JSON {"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}. Exact $0.004 USDC on Base. Try unpaid POST /v1/sandbox/base-proxy first.

## Output

Returns a JSON object indicating whether the address is an upgradeable proxy (true/false), the detected proxy kind (e.g. EIP-1967, UUPS, Transparent, legacy OpenZeppelin, or null), the implementation contract address, the admin address, and the beacon address where applicable. For EOAs or non-proxy contracts, upgradeable_proxy is false and other fields are null.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address": {
   "type": "string",
   "examples": [
    "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
   ],
   "description": "Account on Base mainnet. Example: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (Circle USDC, a legacy OpenZeppelin proxy). Returns implementation, admin, beacon, and proxy_kind. An EOA is upgradeable_proxy false."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-proxy-detection-agentshelf-syntexa-ch-90d41e9e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)