# Nomos Service Health Check

> Nomos Service Health Check is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Checks the health and operational status of a target Nomos Agent Intelligence service endpoint, returning network, product, and risk assessment metadata.

## Facts

- Endpoint: POST https://base-agent-preflight.bytoken2023.workers.dev/x402/v1/service/health
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/nomos-service-health-check-f2d8a9f5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nx21u1utO1NTWE_PMOjO6

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 nomos-service-health-check-f2d8a9f5 -d '<json body>'
```

Example prompt: Can you run a health check on the Nomos agent preflight service at https://base-agent-preflight.bytoken2023.workers.dev/x402/v1/service/health and tell me its current risk level and whether it's operational?

## When to prefer this

Use this endpoint when you need to verify the operational health and risk posture of a Nomos agent service URL before committing resources or executing a paid agent workflow. It is specifically suited for pre-flight validation in autonomous agent pipelines that use x402 pay-per-request patterns on Base/EVM networks, and is preferable to generic HTTP ping checks because it returns structured risk assessments, network context, and product metadata.

## Known failure modes

- Invalid or unreachable target_url returns an error or non-healthy status
- Malformed request schema (missing required 'type' or 'method' fields) results in a 4xx error
- Payment not provided or insufficient USDC triggers a 402 Payment Required response
- target_url exceeding 500 characters or below 8 characters fails schema validation
- Network mismatch between expected_network and actual service network may return elevated risk flags

## 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

Returns a JSON object containing the network identifier (e.g. eip155:8453), the product name (e.g. nomos-service-health), and an assessment object with risk_level (e.g. 'low'), risk_score (numeric), and a flags array indicating any issues detected.

## 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": [
      "POST"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "target_url"
     ],
     "properties": {
      "target_url": {
       "type": "string",
       "maxLength": 500,
       "minLength": 8
      },
      "expected_asset": {
       "type": "string",
       "maxLength": 20,
       "minLength": 2
      },
      "idempotency_key": {
       "type": "string",
       "maxLength": 128
      },
      "expected_network": {
       "type": "string",
       "maxLength": 80,
       "minLength": 2
      }
     }
    }
   },
   "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": "nomos-service-health",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nomos-service-health-check-f2d8a9f5/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)