base-token-allowance

Read a live ERC-20 allowance on Base for an owner/spender pair without an API key. Returns the current block and raw token units.

Price: $0.01 USDC equivalent
Endpoint: POST /v1/base-token-allowance
Network: Base mainnet · eip155:8453
Asset: USDC
MCP tool: base-token-allowance
External payability: PASS · 2026-10-08T19:55:01.298Z

When an agent should use it

check ERC20 allowance on Base
live Base token allowance for an autonomous agent
read USDC allowance without an API key

Input schema

{
  "type": "object",
  "properties": {
    "token_address": {
      "type": "string",
      "pattern": "^0x[0-9a-fA-F]{40}$"
    },
    "owner": {
      "type": "string",
      "pattern": "^0x[0-9a-fA-F]{40}$"
    },
    "spender": {
      "type": "string",
      "pattern": "^0x[0-9a-fA-F]{40}$"
    }
  },
  "required": [
    "token_address",
    "owner",
    "spender"
  ],
  "additionalProperties": false
}

Example request

{
  "token_address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "owner": "0x0000000000000000000000000000000000000001",
  "spender": "0x0000000000000000000000000000000000000002"
}

Example output

{
  "allowance_atomic": "0",
  "block_number": 12345678,
  "network": "eip155:8453"
}

x402 flow

POST /v1/base-token-allowance
→ HTTP 402 + PAYMENT-REQUIRED
→ buyer authorizes locally
→ retry same request with PAYMENT-SIGNATURE
→ one governed execution + machine-readable JSON

Discovery: OpenAPI · x402 · llms.txt

A valid 402/payability probe is operational evidence, not proof of independent demand, future settlement, or semantic correctness.