Paid Agent Studio

Inspiration

Small content jobs combine creative work with quoting, invoicing, payment checks and delivery follow-up. We wanted the agent to carry the payment state through the whole job, with a defined outcome when its draft fails the content checks.

What it does

• Turns seller-supplied product facts into a fixed-price quote for a product page, ads and a short-video script.
• Uses a real PayPal Sandbox guest checkout, verifies the capture and signed webhook, then generates customer copy with live Nebius Nemotron.
• Checks specified unsupported claims, repairs rejected fields once, and offers Markdown/JSON delivery or a full Sandbox refund after two failed checks.

How we built it

Next.js and React provide the Studio and order ledger. A server-side PayPal REST client creates and captures orders, verifies webhook signatures and refunds the original capture. The immutable brief is stored for webhook recovery. Existing AWS DynamoDB storage provides atomic, one-time job claims bound to the brief, order and capture. Signed browser receipts recover saved results. The content client uses OpenAI-compatible structured generation and records model usage. No-key operation is explicitly labeled demo mode.

Tools used

PayPal APIs: Orders v2 creates, retrieves and captures Sandbox orders; Payments v2 checks captures and refunds the original capture. Notifications APIs verify signed webhook deliveries. Stable PayPal idempotency keys and durable job claims guard retries. All PayPal financial traffic is restricted to api-m.sandbox.paypal.com. The integration uses our server-side REST tools, not a claimed PayPal MCP integration.

Nebius Token Factory + Nemotron: nvidia/Nemotron-3_5-Lightning generates live quotes and structured English/Korean copy through the OpenAI-compatible chat completions API. It also corrects rejected text while preserving unflagged fields. If a completed correction still fails, recognized source-fact rules can repair that field; receipts and Markdown disclose these rule repairs, and the whole bundle is checked again. Deterministic checks compare specified claims with supplied product facts; they do not certify all factual accuracy.

Other tools: Next.js, React, Node.js tests, GitHub Actions, Vercel, Playwright, and our existing AWS Lambda/DynamoDB CAS service. Our own Remotion kit renders app captures with English captions and original procedural music on pilot. Codex supported implementation and verification; Claude is the reviewing conductor.

Challenges we ran into

Serverless restarts make process-memory payment state unreliable. Old signed receipts also must not authorize another model run or a refund of delivered work. We bound the job nonce to the order, capture and brief, kept durable completion records, and added webhook cold-start and concurrent-claim tests. Copy checks were refined against observed unsupported English benefits and incomplete Korean sentences.

Accomplishments that we are proud of

Three consecutive production Sandbox deliveries with distinct orders/captures (two English and one Korean), plus a completed USD 39.00 Sandbox refund after two forced content-check failures. Every final customer-copy field was read against its input facts. The 83-test suite and production build pass. Raw downloads, signed webhook logs and direct PayPal API responses are preserved outside the repository.

What we learned

A paid agent needs durable payment and delivery rules as well as a useful model response. Passing a pattern-based content check still requires careful reading of the complete customer copy.

What's next

Improve recovery of interrupted work, expand source-grounding checks, and obtain seller review before any real-money launch. This entry stays Sandbox-only.

What was built during the hackathon

The Studio UI, fixed-price quotes, PayPal Sandbox checkout/capture/webhook/refund tools, durable fulfillment rules, structured bilingual generation, content checks and focused corrections, order ledger, downloads, tests, CI and deployment. The prompt/parser base reuses our own MIT commerce-content-engine code; the motion kit and private CAS storage are existing infrastructure.

License

MIT. Copyright (c) 2026 Kyoungsoo Kim.

Try it out

https://paid-agent-studio.vercel.app

Use fictional product facts. Get a quote, select Continue to PayPal Sandbox, then Sandbox guest card checkout. Generate a US Visa test card with https://developer.paypal.com/sandbox-testing/card-testing/ and choose guest checkout without creating an account. No real money moves. Wait for the Studio to display the delivery, then download Markdown or JSON. The labeled refund scenario deliberately fails both checks. Complete instructions are in the repository README.

Built With

• amazon-dynamodb
• aws-lambda
• nebius-token-factory
• nemotron
• nextjs
• node.js
• paypal
• playwright
• react
• remotion
• vercel