# Nomos MCP Server Risk Check

> Nomos MCP Server Risk 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 2026-09-15).

Performs a risk assessment on a given MCP server URL, returning a risk score, risk level, and any flags indicating suspicious or dangerous behavior.

## Facts

- Endpoint: GET https://base-agent-preflight.bytoken2023.workers.dev/v1/x402/agent/mcp-server-risk-check
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/nomos-mcp-server-risk-check-129cc1a6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_v8IqgDnannFt2NmFrcQIs

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-mcp-server-risk-check-129cc1a6
```

Example prompt: Before connecting to that MCP server at https://myserver.example.com, run a risk check on it — it uses HTTP transport and no authentication — and tell me if it's safe to use.

## When to prefer this

Use this endpoint when an AI agent needs to perform a security preflight check on an MCP server before connecting to or executing tools from it. Prefer this over generic URL scanners when you need MCP-specific risk signals (transport mode, auth mode, exposed tools) returned in a structured agent-readable format with a numeric risk score and actionable flags.

## Known failure modes

- Invalid or unreachable server_url returns an error or degraded assessment
- Missing required 'server_url' query parameter results in a validation error
- Unknown or unsupported transport/auth enum values may yield incomplete scoring
- Payment not received (x402 flow incomplete) results in 402 Payment Required response
- Rate limiting or worker timeout for slow-responding MCP servers

## 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 ('mcp-server-risk-check'), and an assessment object with a numeric risk_score (0–100), a risk_level string (e.g. 'low', 'medium', 'high'), and a flags array listing any specific risk signals detected. May also include identity, activity, and provenance objects with additional context.

## 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": [],
     "properties": {
      "auth": {
       "enum": [
        "none",
        "api_key",
        "bearer",
        "oauth",
        "mTLS",
        "unknown"
       ],
       "type": "string",
       "description": "Authentication mode exposed by the MCP server."
      },
      "tools": {
       "type": "string",
       "maxLength": 2000,
       "description": "Comma-separated MCP tool names when a manifest URL is unavailable."
      },
      "transport": {
       "enum": [
        "stdio",
        "http",
        "sse",
        "websocket",
        "unknown"
       ],
       "type": "string",
       "description": "MCP transport mode."
      },
      "server_url": {
       "type": "string",
       "pattern": "^https?://",
       "maxLength": 2048,
       "description": "Public MCP server, manifest, or connector URL."
      }
     }
    }
   },
   "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": "mcp-server-risk-check",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nomos-mcp-server-risk-check-129cc1a6/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)