Harakiri | Onchain Gossip
Ask what anyone is doing on-chain. The agent pays for the answer with its own wallet.
Live app: https://harakiri-one.vercel.app
The problem
Wallet activity is public, but reading it is not. Block explorers show raw hex, hundreds of spam airdrops and decoded events nobody understands. Good transaction data sits behind API keys and subscriptions. Harakiri turns "what is this wallet up to?" into a plain-English answer: the agent pays for the data itself (per request, over x402, no API key or account) and reports the newest, biggest and weirdest moves, with a link for every claim.
Key features
- An agent with its own wallet. It signs x402 payments (EIP-3009 USDC on Base Sepolia) to buy data from GoldRush, 0.02 USDC per lookup.
- Real mainnet data. Ethereum, Base, Arbitrum, Optimism and Polygon transactions, not mocks.
- ENS resolution. Ask about
vitalik or nick.eth; it finds the address.
- Dossier card. Each lookup shows in/out counts, tokens, and IN / OUT / TAGGED pills that link to the explorer.
- Sus-o-meter. Every answer ends with a 0-10 rating and a one-line reason.
- Spend guardrails in code. At most $0.05 per payment and 2 paid lookups per question; testnet only.
- Prompt-injection defenses. Token names are treated as untrusted data, and only explorer links are clickable (allowlist).
- Multi-wallet questions. Covers 2 wallets per question and names the ones it skipped.
Supported AI models
| Provider | Model | Notes |
|---|
Groq (OpenAI-compatible API, openai SDK 7.25.0) | openai/gpt-oss-120b | Default. Tool calling. |
You can swap in any Groq model that supports tool use with GROQ_MODEL in .env. There is no in-app model switcher.
Tools
| Tool | Cost | What it does |
|---|
resolve_name | Free | ENS name to address. |
get_wallet_activity | 0.02 test USDC (x402) | Newest 40 transactions for an address on a chosen chain, via GoldRush. |
get_my_wallet | Free | The agent's own address and ETH/USDC balance. |
The details are in The tools.
Tech stack
| Layer | What | Version |
|---|
| Runtime | Node.js | 20+ (built on 24.19.0) |
| Framework | Next.js (App Router, API routes) | 16.4.0 |
| UI | React / React DOM | 19.3.0 |
| Styling | Tailwind CSS, shadcn/ui, Base UI | 4.3.3 / 4.21.5 / 1.9.0 |
| Markdown replies | react-markdown, remark-gfm | 10.1.0 / 4.0.1 |
| Icons | lucide-react | 1.57.0 |
| LLM client | openai (pointed at Groq) | 7.25.0 |
| Wallet / chain | viem | 2.57.6 |
| Payments | @x402/core, @x402/fetch, @x402/evm | 2.28.0 |
| Data | GoldRush transactions_v3 over x402 | - |
| Language | TypeScript | 5.9.3 |
Future scope
- Week 3: watchlists with alerts when a followed wallet makes a big move; gossip about NFT and DeFi positions, not just transfers.
- Rate limiting and a per-day spend budget for the public endpoint.
- ZK proof that the agent's data really came from the paid API (verifiable gossip).
- Agent-to-agent: let other agents pay this one over x402 for a gossip report.
Social
How it answers
"What's vitalik doing on-chain?"
- The agent resolves
vitalik to vitalik.eth and then to 0xd8dA…6045 (free ENS lookup).
- It pays GoldRush 0.02 test USDC over x402 for that address's real recent transactions.
- It picks out the newest move, the biggest move, and anything weird, then rates it on a sus-o-meter.
You pay with test USDC on Base Sepolia, but the data is real mainnet activity (Ethereum, Base, Arbitrum, Optimism, Polygon).
Built on the agentmaxxin template (Next.js + a viem wallet), running on Groq through its OpenAI-compatible API.
Prerequisites
- Node.js 20 or newer.
- A free Groq API key from console.groq.com/keys.
- Test USDC on Base Sepolia from Circle's faucet. Each lookup costs 0.02 USDC. You don't need ETH, because x402 payments are gasless signatures and GoldRush's facilitator pays the gas.
Setup
Step 1. Install
npm install
Step 2. Add your Groq key
Create .env in the project root:
GROQ_API_KEY=your_key_here
Step 3. Start the app
npm run dev
Open http://localhost:3000.
Step 4. Create and fund the wallet
- In the Setup panel, click Create wallet. The key is saved to
.agent-wallet.json.
- Copy the address. On faucet.circle.com, pick Base Sepolia and send USDC to it.
- Click refresh next to Balance. It shows ETH and USDC, for example
0 ETH · 10 USDC.
Don't use a well-known test key (such as Hardhat/Anvil's 0xac0974… / 0xf39F…6266) in WALLET_PRIVATE_KEY. Those accounts are EIP-7702-delegated to sweeper contracts on public testnets, and GoldRush rejects their payments with invalid_exact_evm_signature. Use a fresh wallet.
Using it
| Prompt | What happens |
|---|
What's vitalik doing on-chain? | resolve_name → get_wallet_activity on eth-mainnet → gossip and a sus-o-meter. |
Anything sus in jessepollak.eth's Base activity? | Same flow, but on base-mainnet. |
What's in your wallet? | Shows the agent's address and its ETH and USDC balance. |
Each answer comes with a dossier card showing the fetched transactions: in/out counts, tokens, and colored IN / OUT / TAGGED pills (TAGGED means someone else's tx that only airdropped to the address). Each row links to the explorer. The reply ends with a 10-segment sus-o-meter.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
