# X402-BROKER DEX Endpoint — MCP/x402/A2A Gateway

> X402-BROKER DEX Endpoint — MCP/x402/A2A Gateway is a paid API for AI agents from mcp-gateway.agentdiet.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).

Returns DEX (decentralized exchange or service directory) data from the X402-BROKER gateway, which routes across 31,390+ MCP servers, x402 APIs, and A2A agents, settling in USDC on Base.

## Facts

- Endpoint: GET https://mcp-gateway.agentdiet.dev/v1/dex?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-broker-dex-endpoint-mcp-x402-a2a-gateway-263d2e69
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_n-RHCuKa1AJrukKLADhAf

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 x402-broker-dex-endpoint-mcp-x402-a2a-gateway-263d2e69
```

Example prompt: Query the X402-BROKER DEX endpoint to get the current directory of available MCP servers and x402 APIs using a GET request, then show me what services are listed and the ROI compression stats.

## When to prefer this

Choose this endpoint when you need to discover or route across MCP servers, x402-compatible APIs, or A2A agents through a unified broker gateway that settles micropayments in USDC on Base. It is best suited for agents that need directory-style lookups of available tools and services in the x402/MCP ecosystem, especially when cost-per-call efficiency matters (ROI compression). Prefer this over direct MCP server calls when you want centralized routing intelligence.

## Known failure modes

- Missing or malformed `input.type` or `input.method` fields return validation errors
- Invalid token query parameter may return empty or unauthorized data
- Payment failure in x402 flow (0.01 USDC not settled) blocks access
- Service unavailability on the Base network may cause gateway errors
- Empty `data` object returned if no DEX entries match the query

## 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 `data` field containing DEX listing information, a `status` field (e.g. 'ok'), and an `roi_proof` object including a `compression_ratio_pct` value (e.g. 91.4%), indicating the efficiency of the broker's intelligence compression.

## 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": {
      "token": {
       "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/x402-broker-dex-endpoint-mcp-x402-a2a-gateway-263d2e69/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)