# SignGate Stablecoin Health Preflight

> SignGate Stablecoin Health Preflight is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Assesses the risk and health of a stablecoin token on a given chain before an AI agent purchases an x402-gated API, dataset, or tool priced in that stablecoin.

## Facts

- Endpoint: GET https://base-agent-preflight.bytoken2023.workers.dev/v1/x402/agent-risk/stablecoin-health
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signgate-stablecoin-health-preflight-c51f2997
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QqDy9AeLd-T7nCbIajrZF

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 signgate-stablecoin-health-preflight-c51f2997
```

Example prompt: Before my agent pays for that x402 dataset using USDC on Base (token 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48), can you run a stablecoin health preflight on chain eip155:8453 to check the risk score and any flags?

## When to prefer this

Use this endpoint when an AI agent is about to autonomously spend stablecoin funds via x402 and needs a lightweight, fast risk signal on the payment token itself — specifically the stablecoin's health, not the target API's content. Prefer this over general token analytics when you need a pass/fail governance gate before a micropayment, especially on Base (eip155:8453).

## Known failure modes

- Invalid or malformed token address (must be 0x-prefixed 40-char hex) returns validation error
- Unsupported chain identifier returns error or empty assessment
- Token not found or not indexed on specified chain may return null or unknown risk
- Service unavailable on Cloudflare Workers edge returns 5xx
- Payment failure (x402) if USDC payment not processed returns 402

## How this service works

Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.

## Output

A JSON object containing the network identifier, product name ('stablecoin-health'), and an assessment block with risk_level (e.g. 'low'), a numeric risk_score, and an array of flags describing any detected issues with the token's health or safety on the specified chain.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "chain",
      "token"
     ],
     "properties": {
      "chain": {
       "type": "string",
       "pattern": "^[A-Za-z0-9:_ -]{2,80}$"
      },
      "token": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$"
      },
      "use_case": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_.:-]{2,80}$"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "network": {
       "type": "string"
      },
      "product": {
       "type": "string"
      },
      "activity": {
       "type": "object"
      },
      "identity": {
       "type": "object"
      },
      "assessment": {
       "type": "object"
      },
      "provenance": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "network": "eip155:8453",
  "product": "stablecoin-health",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signgate-stablecoin-health-preflight-c51f2997/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-agent-preflight.bytoken2023.workers.dev](https://www.zero.xyz/host/base-agent-preflight.bytoken2023.workers.dev/llms.txt)