mcp_approval_pack

What is mcp_approval_pack?

mcp_approval_pack is a paid work product in the MCP Trust category on agenttoll.dev. It costs $0.05 per call, settled in USDC on Base via the x402 payment protocol. No API keys or accounts: your agent inspects the metadata, explains the expected result, caps the spend, calls the tool, and receives structured JSON with a receipt envelope.

Input parameters

Only send these request-body fields. If this block is empty, send {}.

{
  "tool_name": "optional tool name",
  "route_url": "optional route URL",
  "price_usd": "optional number or string",
  "task_intent": "optional user task",
  "max_payment_usd": "optional number or string",
  "tool_schema": "optional tool schema object or JSON string",
  "method": "optional HTTP method",
  "seller_address": "optional 0x seller wallet"
}

Request body

{
  "tool_name": "x402_market_radar",
  "route_url": "https://agenttoll.dev/paid/x402/market-radar",
  "price_usd": "0.05",
  "task_intent": "check x402 market demand",
  "max_payment_usd": "0.05",
  "tool_schema": {
    "name": "x402_market_radar",
    "description": "Return an x402 catalog and ranking brief for agent buyers.",
    "properties": {
      "query_limit": {
        "type": "integer"
      }
    }
  },
  "seller_address": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1"
}

HTTP endpoint

POST JSON to this URL. The first unpaid call returns HTTP 402 with x402 payment requirements; an x402-capable client signs and retries.

https://agenttoll.dev/paid/mcp/approval-pack

MCP call

Connect an MCP client to the endpoint, call tool mcp_approval_pack, and pass the request body as arguments.

https://agenttoll.dev/mcp

MCP paid-tool calls may surface the payment challenge inside the JSON-RPC result instead of as a raw HTTP 402.

What the agent needs to transact

{
  "mcp": {
    "endpoint": "https://agenttoll.dev/mcp",
    "tool": "mcp_approval_pack",
    "arguments": {
      "tool_name": "x402_market_radar",
      "route_url": "https://agenttoll.dev/paid/x402/market-radar",
      "price_usd": "0.05",
      "task_intent": "check x402 market demand",
      "max_payment_usd": "0.05",
      "tool_schema": {
        "name": "x402_market_radar",
        "description": "Return an x402 catalog and ranking brief for agent buyers.",
        "properties": {
          "query_limit": {
            "type": "integer"
          }
        }
      },
      "seller_address": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1"
    }
  },
  "http": {
    "method": "POST",
    "url": "https://agenttoll.dev/paid/mcp/approval-pack",
    "headers": {
      "content-type": "application/json"
    },
    "body": {
      "tool_name": "x402_market_radar",
      "route_url": "https://agenttoll.dev/paid/x402/market-radar",
      "price_usd": "0.05",
      "task_intent": "check x402 market demand",
      "max_payment_usd": "0.05",
      "tool_schema": {
        "name": "x402_market_radar",
        "description": "Return an x402 catalog and ranking brief for agent buyers.",
        "properties": {
          "query_limit": {
            "type": "integer"
          }
        }
      },
      "seller_address": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1"
    },
    "unpaid_response": "HTTP 402 with x402 payment requirements",
    "paid_response": "HTTP 200 JSON with payment-response receipt header"
  },
  "payment": {
    "protocol": "x402",
    "scheme": "exact",
    "price_usd": "0.05",
    "max_payment_usd": "0.05",
    "network": "eip155:8453",
    "network_name": "Base mainnet",
    "asset": "USDC",
    "asset_address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "pay_to": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1"
  },
  "expected_result": "JSON approval pack with maxPayment, seller checks, approval prompt, risk reasons, allowed fields, blocked fields, and receipt envelope.",
  "approval_prompt": "This AgentToll call costs $0.05 on Base mainnet. Verify payTo 0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1, asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, and maxPayment $0.05 before approving. It returns JSON approval pack with maxPayment, seller checks, approval prompt, risk reasons, allowed fields, blocked fields, and receipt envelope.",
  "receipt": "https://agenttoll.dev/receipt/:tx",
  "receipt_schema": "https://agenttoll.dev/agenttoll-receipt-v1.md"
}

Agent approval metadata

Use this before asking a user to approve payment. It states the cap, seller wallet, asset, route, and expected result in one buyer contract.

Suggested approval line: This AgentToll call costs $0.05 on Base mainnet. Verify payTo 0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1, asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, and maxPayment $0.05 before approving. It returns JSON approval pack with maxPayment, seller checks, approval prompt, risk reasons, allowed fields, blocked fields, and receipt envelope.

{
  "schemaVersion": "agenttoll.buyer_contract.v1",
  "service": "agenttoll.dev",
  "tool": "mcp_approval_pack",
  "category": "MCP Trust",
  "method": "POST",
  "endpoint": "https://agenttoll.dev/paid/mcp/approval-pack",
  "priceUsd": "0.05",
  "maxPaymentUsd": "0.05",
  "protocol": "x402",
  "scheme": "exact",
  "network": "eip155:8453",
  "networkName": "Base mainnet",
  "asset": "USDC",
  "assetContract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "payTo": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1",
  "facilitator": "https://api.cdp.coinbase.com/platform/v2/x402",
  "requestBody": {
    "tool_name": "x402_market_radar",
    "route_url": "https://agenttoll.dev/paid/x402/market-radar",
    "price_usd": "0.05",
    "task_intent": "check x402 market demand",
    "max_payment_usd": "0.05",
    "tool_schema": {
      "name": "x402_market_radar",
      "description": "Return an x402 catalog and ranking brief for agent buyers.",
      "properties": {
        "query_limit": {
          "type": "integer"
        }
      }
    },
    "seller_address": "0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1"
  },
  "input": {
    "tool_name": "optional tool name",
    "route_url": "optional route URL",
    "price_usd": "optional number or string",
    "task_intent": "optional user task",
    "max_payment_usd": "optional number or string",
    "tool_schema": "optional tool schema object or JSON string",
    "method": "optional HTTP method",
    "seller_address": "optional 0x seller wallet"
  },
  "expectedResult": "JSON approval pack with maxPayment, seller checks, approval prompt, risk reasons, allowed fields, blocked fields, and receipt envelope.",
  "verifyBeforePaying": [
    "network must equal eip155:8453",
    "asset contract must equal 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "payTo must equal 0x62a0D3d9DF0dE8804983009949c714EaeAFd87F1",
    "maxPayment must be no more than $0.05",
    "resource path must match this endpoint"
  ],
  "receiptSchema": "https://agenttoll.dev/agenttoll-receipt-v1.md"
}

Pricing & payment

Paid JSON responses include agenttoll_receipt with request, result, and payment-term hashes. The receipt lets a user audit what the agent bought after the call. If your buyer runtime exposes a settlement transaction hash, verify it at /receipt/<tx>.

FAQ