# Assay A2A & MCP Security Observatory

> Assay A2A & MCP Security Observatory is a paid API for AI agents from assay.agentdiet.dev, paid per call via x402 or MPP, $0.005/call, status unknown (last checked 2026-10-21).

Runs a cryptographic pre-flight security audit, schema conformance check, and TDQS reputation scoring on A2A, MCP, or x402 endpoints, returning a grade, score, and allow/deny verdict.

## Facts

- Endpoint: GET https://assay.agentdiet.dev/v1/certify?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402, MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/assay-a2a-mcp-security-observatory-cc932127
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Oiw3lsHYrU_LAkX6Z7T80

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 assay-a2a-mcp-security-observatory-cc932127
```

Example prompt: Run a security audit on https://payments.example.com using a GET request and tell me if it passes — I need the trust grade and verdict before I connect my agent to it.

## When to prefer this

Choose this endpoint when you need a structured, scored security verdict on an agentic endpoint (A2A, MCP, or x402) before connecting or integrating it — especially when you require a letter grade, TDQS reputation score, schema conformance check, and a formal allow/deny verdict in a single call. Prefer it over generic port scanners or HTTP linters when the target is specifically an AI agent protocol endpoint and you need audit receipts for compliance or logging.

## Known failure modes

- Target URL is unreachable or returns non-standard responses — audit may fail or return incomplete dossier
- Invalid or missing 'target' query parameter — request rejected with schema validation error
- Endpoint does not conform to A2A/MCP/x402 protocols — may return low score or deny verdict
- Payment not attached or insufficient USDC — x402 payment required error
- Target URL times out during cryptographic probe — partial or failed audit result

## How this service works

Live A2A & MCP endpoint security auditor, Tool Definition Quality Score (TDQS) certifier, prompt-injection scanner, and cryptographic trust oracle.

## Output

Returns a JSON object containing a 'dossier' with a letter grade (e.g. 'A'), a numeric score (0-100), and the audited target URL; a 'verdict' of 'allow' or 'deny'; and a 'receipt' token string for record-keeping.

## 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",
      "POST"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "target": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "dossier": {
   "grade": "A",
   "score": 95,
   "target": "https://example.com"
  },
  "receipt": "asr_rcpt_sample",
  "verdict": "allow"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/assay-a2a-mcp-security-observatory-cc932127/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from assay.agentdiet.dev](https://www.zero.xyz/host/assay.agentdiet.dev/llms.txt)