Ekx Coinbase Cdp

Coinbase CDP + OnchainKit

Two distinct things from the same vendor:

• CDP Server Wallets — keys held by our backend, so an agent can transact.
• OnchainKit — React components for Base dApps.

Portal: https://portal.cdp.coinbase.com · Docs: https://docs.cdp.coinbase.com

When CDP instead of Privy

An agent app needs CDP when its LangGraph agent books and moves USDC without a human clicking. That is the only justification for a server-held key — if a human is in the loop, use Privy.

Environment

CDP_API_KEY_ID=                 # SECRET
CDP_API_KEY_SECRET=             # SECRET
NEXT_PUBLIC_CDP_PROJECT_ID=     # public
AGENT_WALLET_ID=                # SECRET — the persisted wallet id

Server wallets

import { CdpClient } from "@coinbase/cdp-sdk";

const cdp = new CdpClient({
  apiKeyId: process.env.CDP_API_KEY_ID!,
  apiKeySecret: process.env.CDP_API_KEY_SECRET!,
});

const account = await cdp.evm.getOrCreateAccount({ name: "rental-agent" });

const { transactionHash } = await cdp.evm.sendTransaction({
  address: account.address,
  network: "base-sepolia",
  transaction: { to: USDC, data: encodedTransfer, value: 0n },
});

Persist the wallet id. A server wallet that is re-created on each deploy is a new address with no funds and no history — and the old one's balance is stranded. Store AGENT_WALLET_ID in the environment and look it up, never create blindly.

Fund the agent wallet with a float, not a treasury. It signs without human approval by definition; cap the blast radius.

AgentKit

@coinbase/agentkit + @coinbase/agentkit-langchain expose onchain actions as LLM tools, driven by @langchain/langgraph.

const agentkit = await AgentKit.from({ walletProvider });
const tools = await getLangChainTools(agentkit);
const agent = createReactAgent({ llm, tools, checkpointSaver: memory });

Note this is the one place in the portfolio using LangChain and OpenAI — inherited from the AgentKit starter. Everything else is the Anthropic SDK directly (skill). On a rebuild, prefer Claude with native tool use over the LangChain layer; the abstraction earns little here.

Constrain the tool set. AgentKit ships transfer and trade actions by default. An agent with an unbounded transfer tool and a funded wallet is one prompt-injection away from being drained. Register only the actions the product needs.

OnchainKit

import { OnchainKitProvider } from "@coinbase/onchainkit";
import { base } from "viem/chains";

<OnchainKitProvider apiKey={process.env.NEXT_PUBLIC_CDP_PROJECT_ID} chain={base}>
  {children}
</OnchainKitProvider>

Components worth using rather than rebuilding: <Wallet /> (connect + dropdown), <Identity /> / <Name /> / <Avatar /> (ENS + Basename resolution), <Swap />, <Checkout />, <Transaction /> (handles the receipt-waiting and status UI we otherwise hand-roll).

Add @farcaster/miniapp-wagmi-connector to run as a Base App / Farcaster miniapp — the connector replaces the normal wallet connection when the app is embedded in a Farcaster client.

OnchainKit needs its own stylesheet: import "@coinbase/onchainkit/styles.css". Missing it renders unstyled components, which reads as broken rather than unstyled.

Gotchas

1. Re-created server wallets strand funds. Persist the id.
2. Unbounded agent tools + funded wallet = drainable. Constrain.
3. styles.css import for OnchainKit.
4. Identity components need an L1 RPC for ENS. Basenames resolve on Base; .eth does not.
5. CDP network names are strings ("base-sepolia"), not chain ids.