Onchain SQL schema

The table + column schema for the onchain-sql tool - every queryable table (base.events, base.transactions, base.blocks, base.decoded_user_operations, base.transaction_attributions, solana.instructions, …) with its columns and types. Send GET /api/onchain-sql-schema with no input and pay $0.002 per call over x402 or MPP (there is no free tier). It returns a JSON object with schema.

Fetch once, then write SQL with confidence.

Category: Wallet operations · Tags: cdp coinbase wallet onboarding x402 agent-wallet sql schema

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Parameters

Onchain SQL schema takes no parameters.

Example request

curl -i "https://agent402.tools/api/onchain-sql-schema"

Without payment this returns HTTP 402 Payment Required with the exact price for onchain-sql-schema; any x402 v2 or MPP client pays it and retries.

Example response

{
  "schema": {
    "base.events": [
      {
        "name": "block_number",
        "type": "UInt64"
      }
    ]
  }
}

From an MCP client

catalog.call {
  "slug": "onchain-sql-schema",
  "params": {}
}

The hosted connector at https://agent402.tools/mcp needs a payment for onchain-sql-schema; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• There is no input to get wrong: any request to /api/onchain-sql-schema runs the tool.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key (Authorization: Bearer a402_...) also pays it.
• A POST with a JSON body to /api/onchain-sql-schema is served as this GET, with the body as the input.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/onchain-sql-schema");

Part of these workflows

Onchain SQL schema is one step in this skill pack, each sold as a single call:

• Onchain analyst (SQL over Base) - Ask Base anything in one paid call: your SQL runs against Coinbase's indexed, DECODED chain data (events with parsed parameters, transactions, blocks, user-ops) with the live schema alongside - no indexer, no RPC archaeology.

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