# AgentDiet MCP Gateway Guard Endpoint

> AgentDiet MCP Gateway Guard Endpoint is a paid API for AI agents from mcp-gateway.agentdiet.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-22).

Acts as a deterministic routing and execution guard node for accessing 31,390+ MCP servers, x402 APIs, and A2A agents, settling micropayments in USDC on Base.

## Facts

- Endpoint: GET https://mcp-gateway.agentdiet.dev/v1/guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentdiet-mcp-gateway-guard-endpoint-ede1b6ea
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JF2rOzONwioSjn58gGtpS

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 agentdiet-mcp-gateway-guard-endpoint-ede1b6ea
```

Example prompt: Route my GET request through the AgentDiet MCP gateway guard to fetch data about 'large language models', using HTTP type and GET method, and settle the $0.005 USDC payment on Base.

## When to prefer this

Choose this endpoint when you need a single unified broker to access a large catalog of MCP servers, x402 APIs, or A2A agents without managing individual payment channels or protocol handshakes. It is best suited for agents that need deterministic routing with automatic USDC micropayment settlement on Base, especially when you want ROI proof metrics alongside execution results.

## Known failure modes

- Insufficient USDC balance causes payment failure and 402 response
- Invalid or missing 'type' and 'method' fields in input object return a 400 validation error
- Unreachable downstream MCP server results in timeout or error propagation
- Malformed queryParams object causes schema validation rejection
- Non-whitelisted HTTP methods (anything other than GET or POST) are rejected

## How this service works

Deterministic B2A/A2A/MCP/x402/MPP/L402 execution and intelligence node at https://mcp-gateway.agentdiet.dev settling in USDC on Base.

## Output

Returns a JSON object with a 'status' field (e.g. 'ok'), a 'data' object containing the routed response payload, and an 'roi_proof' object that includes a compression_ratio_pct metric indicating efficiency of the brokered call.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "status": "ok",
  "roi_proof": {
   "compression_ratio_pct": 91.4
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentdiet-mcp-gateway-guard-endpoint-ede1b6ea/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-gateway.agentdiet.dev](https://www.zero.xyz/host/mcp-gateway.agentdiet.dev/llms.txt)