# ZayGuard Transaction Assessment

> ZayGuard Transaction Assessment is a paid API for AI agents from zayguard.onrender.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Simulates and assesses a proposed Base blockchain transaction read-only, returning a risk/safety evaluation before execution.

## Facts

- Endpoint: POST https://zayguard.onrender.com/v1/assessments
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/zayguard-transaction-assessment-aab53d3d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FdXwnbQ74bENZ-Rv9OYuS

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 zayguard-transaction-assessment-aab53d3d -d '<json body>'
```

Example prompt: Before I sign this transaction, can you run it through ZayGuard to assess whether it's safe? The sender is 0xAbCd1234567890abcdef1234567890abcdef1234, recipient contract is 0xDeadBeef00000000000000000000000000000001, with calldata 0xa9059cbb000000000000000000000000 and 0 ETH value on Base.

## When to prefer this

Choose ZayGuard when you need a lightweight, pay-per-call transaction pre-flight check on Base before committing a signature. It is ideal for AI agents that autonomously execute on-chain actions and need a safety gate, or for wallets wanting a second opinion on suspicious contract calls. Prefer it over general blockchain explorers when you need a structured machine-readable risk assessment rather than raw transaction data.

## Known failure modes

- Invalid Ethereum address format for from_address or to_address returns a 400 validation error
- Malformed calldata not matching hex pattern returns a 400 schema error
- Non-Base chain specified returns a 400 error since only 'base' is supported
- Unpayable or missing x402 payment header results in a 402 Payment Required response
- Service unavailability on Render hosting may return 503 errors
- Calldata referencing contracts not deployed on Base may return inconclusive or error results

## How this service works

Agent-facing assessment intelligence: pay $0.05 USDC through x402 for a read-only Base transaction result.

## Output

Returns a read-only assessment of the proposed Base transaction, including risk signals, simulation outcome, and safety verdict — without executing or modifying any on-chain state.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "string",
   "pattern": "^0x(?:[0-9a-fA-F]{2})*$",
   "description": "Optional calldata."
  },
  "chain": {
   "enum": [
    "base",
    "arbitrum"
   ],
   "type": "string",
   "description": "Network being assessed. Base or Arbitrum One."
  },
  "value_wei": {
   "type": "integer",
   "default": 0,
   "minimum": 0,
   "description": "Optional proposed native-value amount in wei."
  },
  "to_address": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Proposed recipient or contract: canonical lowercase or valid EIP-55 checksummed EVM address."
  },
  "from_address": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Proposed transaction sender: canonical lowercase or valid EIP-55 checksummed EVM address."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zayguard-transaction-assessment-aab53d3d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from zayguard.onrender.com](https://www.zero.xyz/host/zayguard.onrender.com/llms.txt)