SARA - Stellar Autonomous Research Agent

An AI-powered research agent that autonomously discovers, evaluates, and pays for data services on the Stellar blockchain using x402 micropayments — all within a user-specified USDC budget.

What It Does

1. You ask a research question (e.g., "What's happening in crypto markets today and how might global news affect Bitcoin?")
2. You set a USDC budget (e.g., $0.10)
3. An AI agent autonomously:
   • Decomposes your query into data-gathering sub-tasks
   • Discovers available paid data services via the xlm402.com catalog
   • Calls each service by paying USDC via x402 on Stellar testnet
   • Tracks spending against your budget in real-time
   • Synthesizes all findings into a comprehensive research report
4. You see everything live: each API call, its cost, the Stellar transaction hash, and the final report

Why This Matters

Agents can reason and plan — but they still can't pay. x402 on Stellar changes that. SARA demonstrates what happens when AI agents get their own wallet and can make economic decisions: choosing which data to buy, how much to spend, and when to stop — using real stablecoin micropayments on a real blockchain.

Architecture

User (Browser)
  └─> Next.js Frontend
        └─> POST /api/research (SSE stream)
              └─> Orchestrator Agent (OpenAI GPT-5.1, function calling)
                    ├─> Fetches service catalog from xlm402.com
                    ├─> Plans sub-tasks based on query
                    ├─> For each task:
                    │     ├─> Calls x402 endpoint (pays USDC on Stellar)
                    │     └─> Collects results
                    └─> Synthesizes report with cost breakdown

Available Data Services (via xlm402.com testnet)

Service	Endpoints	Cost/call
Weather	Current, forecast, archive, history summary	$0.01
News	13 categories (tech, AI, crypto, business, etc.)	$0.01
Crypto	Quote, candles (OHLCV)	$0.01
Web Scrape	Extract content from any public URL	$0.03
Data Collect	Bounded same-origin crawl	$0.08

Tech Stack

• Frontend: Next.js 16, React 19, Tailwind CSS 4
• AI Orchestration: OpenAI GPT-5.1 with function calling
• Payments: x402 protocol on Stellar testnet (USDC)
• Blockchain: Stellar testnet via @stellar/stellar-sdk
• x402 SDK: @x402/fetch, @x402/stellar, @x402/core
• Data Services: xlm402.com (44 paid endpoints)

Setup

Prerequisites

• Node.js 18+
• OpenAI API key
• Testnet USDC (free from Circle faucet)

1. Install Dependencies

cd stellar-sara
npm install

2. Create a Stellar Testnet Wallet

npx tsx scripts/setup-wallet.ts

This generates a new keypair, funds it with testnet XLM via Friendbot, and creates a USDC trustline.

3. Fund with Testnet USDC

1. Go to https://faucet.circle.com/
2. Select Stellar Testnet
3. Paste your public key from step 2
4. Request testnet USDC

4. Configure Environment

Edit .env.local and add your OpenAI API key:

OPENAI_API_KEY=sk-...
STELLAR_PRIVATE_KEY=S...  # Already set by setup script
STELLAR_PUBLIC_KEY=G...   # Already set by setup script

5. Run

npm run dev

Open http://localhost:3000

How x402 Payments Work

1. The agent makes a standard HTTP request to a paid endpoint on xlm402.com
2. The server responds with 402 Payment Required + payment details
3. The x402 SDK automatically signs a USDC payment on Stellar
4. The request is retried with the signed payment header
5. The facilitator verifies and settles the payment on-chain
6. The agent receives the data

All of this happens in a single fetch() call thanks to wrapFetchWithPayment().

Example Research Queries

• "What's happening in the crypto market today and how might global economic news affect Bitcoin?"
  • Chains: crypto quote + candles + news/blockchain + news/economics
• "What's the weather like in major tech hubs and what's the latest in AI?"
  • Chains: weather/current (multiple cities) + news/tech + news/ai
• "Research the latest cybersecurity threats and their potential impact on blockchain"
  • Chains: news/security + news/blockchain + scrape (relevant URLs)

Key Features

• Budget-constrained autonomy: The agent decides what to pay for within your budget
• Real Stellar transactions: Every API call is a real USDC payment on Stellar testnet
• Live cost tracking: Watch your budget deplete in real-time with transaction links
• Service discovery: Agent programmatically discovers available services from the xlm402.com catalog
• Streaming UI: Server-Sent Events stream every step of the agent's decision process

Limitations & Future Work

• Currently uses xlm402.com testnet endpoints only (no mainnet spending)
• AI chat/image services are mainnet-only on xlm402.com, so they're not included
• Could be extended with MPP session mode for high-frequency streaming data
• Budget optimization could be improved with cost/value scoring