MCP Tool · x402 · early usage

Query real-time stablecoin supply yield pools from Barker's index of 500+ DeFi protocols

Query real-time stablecoin supply yield pools from Barker's index of 500+ DeFi protocols. Returns ranked rows with protocol_name, chain_name, asset_symbol, supply_apy_total (decimal — multiply by 100 for %), and supply_tvl (USD). Use for questions like 'best…

by mcp.barker.money · discovered, not yet claimed by its owner · updated 2026-10-13

30d calls69

30d payers6

MethodGET

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Tags: bazaar

Call contract

Method: GET
Input: query parameters
Output: json
Last paid call: 2026-10-13

Input example from Bazaar metadata

{
  "asset": "usdc",
  "chain": "base",
  "limit": 10,
  "sort": "apy"
}

Output example

{
  "data": [
    {
      "asset_symbol": "USDC",
      "chain_name": "ethereum",
      "pool_uid": "aave-v3_ethereum_usdc_supply",
      "protocol_name": "Aave V3",
      "supply_apy_total": 0.0523,
      "supply_tvl": 1234567890
    }
  ],
  "success": true
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/28918.json for the price and payment options.
Pay. Call GET https://mcp.barker.money/barker_defi_vaults. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on eip155:196, Base, Ethereum, Polygon, Arbitrum One, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.001 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: eip155:196, Base, Ethereum, Polygon, Arbitrum One
Demand: 69 calls · 6 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	eip155:196 eip155:196	0x779ded0c9e1022225f8e0630b35a9b54be713736	1000	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	300s
aggr_deferred	eip155:196 eip155:196	0x779ded0c9e1022225f8e0630b35a9b54be713736	1000	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	300s
exact	Base eip155:8453	USDC	$0.001	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	300s
exact	Ethereum eip155:1	0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48	1000	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	600s
exact	Polygon eip155:137	USDC	$0.001	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	600s
exact	Arbitrum One eip155:42161	USDC	$0.001	0x83f15f5bea445109e255ab82622fbdfecd1e4c9f	600s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:196",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0x779ded0c9e1022225f8e0630b35a9b54be713736",
    "amount": "1000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "aggr_deferred",
    "network": "eip155:196",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0x779ded0c9e1022225f8e0630b35a9b54be713736",
    "amount": "1000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "1000",
    "amountUsd": 0.001,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:1",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    "amount": "1000",
    "maxTimeoutSeconds": 600
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "1000",
    "amountUsd": 0.001,
    "maxTimeoutSeconds": 600
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0x83f15f5bea445109e255ab82622fbdfecd1e4c9f",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "1000",
    "amountUsd": 0.001,
    "maxTimeoutSeconds": 600
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://mcp.barker.money/barker_defi_vaults"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://mcp.barker.money/barker_defi_vaults");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://mcp.barker.money/barker_defi_vaults")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: mcp.barker.money
Endpoint: https://mcp.barker.money/barker_defi_vaults
Machine-readable: /resources/28918.json