DeFi Trading Agent

A LangChain + LangGraph ReAct agent powered by GPT-4o that autonomously trades within policy guardrails.

What It Demonstrates

• LangChain + LangGraph ReAct agent with GPT-4o
• Policy-governed autonomous trading within spending limits
• Session keys for scoped agent access
• All 5 LangChain tools in action

Architecture

GPT-4o (LLM)
    |
LangGraph ReAct Agent
    |
SmartAgentKit LangChain Tools
    |
SmartAgentKit SDK --> Bundler --> On-Chain

The agent uses a reasoning loop: it checks balances, evaluates spending limits, decides on trades, and executes transactions -- all through the SmartAgentKit LangChain tools.

Quick Start

cd apps/examples/defi-trading-agent

# Mock mode (no API keys needed)
pnpm start:mock

# Testnet mode
cp .env.example .env
# Fill in the required variables (see below)
pnpm start

Configuration

Variable	Description	Required
OPENAI_API_KEY	OpenAI API key	Testnet only
RPC_URL	Base Sepolia RPC	Testnet only
BUNDLER_URL	Pimlico bundler URL	Testnet only
OWNER_PRIVATE_KEY	Wallet owner key	Testnet only

Preset: defi-trader

This example uses the defi-trader preset, which configures:

• Spending limit: 1 ETH per day (rolling window)
• Allowlist: Configured DEX contract addresses only
• Emergency pause: 24-hour auto-unpause, guardian = owner

Key Code Highlights

Tool Creation

The example uses createSmartAgentKitTools() to generate LangChain-compatible tools:

import { createSmartAgentKitTools } from "@smartagentkit/langchain";

const tools = createSmartAgentKitTools(client, walletAddress, sessionKey);

Agent Behavior

The ReAct agent reasons about:

1. Current wallet balance and spending limits
2. Whether a trade is within policy bounds
3. Transaction execution and result verification

Session Keys

Session keys provide time-limited access for the agent, scoped to specific contracts and function selectors. The owner creates a session, and the agent uses the session key for all operations.

Source Code

See apps/examples/defi-trading-agent/ in the repository.