Agentbot Goes Onchain
Builder Codes, NFTs & Swaps

Last night we shipped three major Base ecosystem integrations in a single session: Builder Codes for onchain attribution, NFT wristbands for community access, and token swaps via the CDP Trade API. Here's what we built and how it works.

How It Works

A Builder Code is a unique string (e.g. bc_4k0319ta) that gets encoded into the last bytes of your transaction data. Smart contracts ignore the suffix — it's extracted by offchain indexers after the fact. Gas overhead is minimal (16 gas per non-zero byte).

Our Implementation

We integrated Builder Codes at the wagmi config level, meaning every transaction from Agentbot automatically includes the attribution. Here's the setup:

import { Attribution } from "ox/erc8021";

const BUILDER_CODE = 'bc_4k0319ta';

const DATA_SUFFIX = Attribution.toDataSuffix({
  codes: [BUILDER_CODE],
});

export const wagmiConfig = createConfig({
  chains: [base, baseSepolia],
  connectors: [coinbaseWallet({ appName: 'Agentbot' })],
  transports: {
    [base.id]: http(),
    [baseSepolia.id]: http(),
  },
  dataSuffix: DATA_SUFFIX,  // Every tx includes this
});

The critical fix was ensuring WalletProvider imports this config instead of creating its own. Without this, the dataSuffix was dead code — transactions went out unattributed.

What You See on Base

Once users start sending onchain transactions (minting NFTs, swapping tokens), your activity appears on the Base App Leaderboard. You'll see:

• Total transacting users
• Number of transactions
• Gas spent
• Paymaster subsidies

The Flow

Users visit agentbot.sh/wristband and see one of three states:

Smart Wallet Detection

The component detects wallet connections through multiple layers:

• wagmi hooks — useAccount() for managed connections
• window.ethereum — fallback detection for any EVM wallet
• useCustomSession — email auth state from NextAuth

CDP Paymaster (Gasless)

We integrated the CDP Paymaster for gasless minting. The user pays nothing — CDP sponsors the gas from your $500 monthly allowance. Setup requires:

1. CDP account with payment method in Billing
2. Paymaster endpoint URL from Onchain Tools
3. NFT contract allowlisted in Paymaster config

Supported Tokens

How to Swap

1. Navigate to agentbot.sh/dashboard/swap
2. Connect your Base wallet
3. Select tokens and enter amount
4. Review the quote (rate, price impact, slippage)
5. Confirm the swap in your wallet

API Architecture

The swap flow uses a two-step process:

// 1. Get price estimate (debounced, fast)
POST /api/swap
{ action: "quote", fromToken, toToken, fromAmount, walletAddress }

// 2. Execute swap (requires wallet signature)
POST /api/swap
{ action: "swap", fromToken, toToken, fromAmount, walletAddress }

The backend uses the @coinbase/cdp-sdk for quote generation and execution. Slippage protection is built in (1% default). Every swap includes Builder Code attribution automatically.

Setup

BRIDGE_SECRET=your_secret bash <(curl -sSL https://agentbot.sh/bridge/install.sh)

The bridge client polls the server every 3 seconds, receives requests, runs them through your local OpenClaw, and sends responses back. Your data stays on your machine.

• →

  Deploy Real NFT Contract

  The CDP example contract doesn't exist on mainnet. Deploy via Remix IDE or thirdweb.

• →

  Add CDP Billing

  Enable gasless mints by adding a payment method in CDP Portal → Billing.

• →

  Base Notifications

  Push updates to users who pinned Agentbot in the Base App.

• →

  Base MCP Integration

  Give agents a wallet. Check balances, send funds, pay x402 APIs.