Stoop

Sell anything without meeting anyone. Money moves only when your porch camera sees it go.

Try it: https://d29kyjvj1jibpu.cloudfront.net Open a shop, photograph something you'd sell, send the link to a friend, and use an old phone or a laptop as the porch camera. No sign-up; test payments only, nothing is ever charged.

Judges: the same app plus the Alexa+ device demo (seller and buyer side by side) at https://d2h8mmod981k0j.cloudfront.net/demo

Watch a whole sale in under 100 seconds: the walkthrough video plays on the home page (apps/web/public/demo.mp4, recorded by services/stack/e2e/record-walkthrough.ts).

Stoop is an Alexa+ add-on (MCP server + MCP Apps cards) and a Ring Appstore app.

• You tell your assistant "Sell the stroller and the bike. Don't go below $90 on the stroller."

• Stoop prices and lists them, then negotiates with buyers, including buyers' own AI assistants. It never knows or reveals your minimum.

• The buyer pays through an Alexa+-style checkout. The money is held, not charged.

• The buyer picks the item up off your porch. Your porch camera provides the proof of handoff: check-in, someone at the door, item there before and gone after. In the live app the camera is any old phone or laptop; the Ring integration (Partner API client, signed webhooks, simulator) does the same with a Ring doorbell. Only then is the money released, with a signed receipt anyone can verify.

The AI never holds the keys. Money, your address and receipts are controlled by a separate Settlement service under deterministic rules. In a 300-attack red team on Amazon Bedrock (Nova 2 Lite), a naive agent with the address in its prompt leaked it 57 times (19%); Stoop's agent leaked it 0 times, because it never had it (evals/REPORT.md).

Run it (Windows, macOS or Linux; Node 22)

git clone https://github.com/hash066/stoop.git
cd stoop
corepack enable     # provides the pinned pnpm (11.0.8)
pnpm install
pnpm demo

The submission video's shot list is docs/DEMO_SCRIPT.md. Everything runs offline by default. LLM_MODE=bedrock switches agents and vision to Amazon Bedrock (see .env.example).

Hosted mode: what testers and judges get

The Stoop web app (apps/web) is the product with no simulation in the flow:

• Seller: opens a shop with their real pickup address (encrypted; buyers see it only on their pass, during their window) and uploads photos. Bedrock names and prices each one; an AI estimate is labelled as one. They list with a private lowest price and share the link.

• Buyer: on another device, asks and haggles with the seller's assistant (typed or spoken, through the same MCP tools and planner an Alexa+ device uses). They pay (held, not charged) and open the pickup pass on their phone.

• Porch camera: any phone or laptop running the camera page. It takes the before and after photos, and during a pickup its motion detector asks Bedrock vision whether a person is at the door (counted, never identified).

• Handoff: the buyer taps I'm Here, the camera sees someone and then the item gone, and the money moves with a signed receipt. If the camera can't tell, both people confirm.

Each shop is its own private world. The Alexa+ device tour (seeded demo household, labelled simulator) lives at /demo.

pnpm build:web
PORT=8080 ADMIN_KEY=local pnpm serve       # http://localhost:8080 (web app), /demo (device tour)
pnpm --filter @stoop/stack e2e             # seller, buyer phone and camera phone in three Chrome profiles, end to end
pnpm tour http://localhost:8080 local      # drives the device tour in Chrome

Docker image: Dockerfile. AWS deployment (CloudFront + one instance running both sites on Amazon Bedrock, plus the negotiator on AgentCore Runtime): docs/DEPLOY.md.

Related MCP server: genpark-agentic-delegated-escrow-settlement-ledger-skill

Amazon SDKs and protocols, and where they are used

Connect your own MCP client

The live servers speak MCP 2025-11-25 over Streamable HTTP, so any client can use them. With the official MCP Inspector:

# open a shop (no sign-up); the reply has the shop id and the seller's token
curl -s -X POST https://d29kyjvj1jibpu.cloudfront.net/api/shops -H 'Content-Type: application/json' -H 'Origin: https://d29kyjvj1jibpu.cloudfront.net' \
  -d '{"displayName":"Judge","address":"1 Test Way, Springfield, IL","zip":"62704","porchInstructions":"On the bench"}'

npx @modelcontextprotocol/inspector --cli https://d29kyjvj1jibpu.cloudfront.net/s/<id>/mcp/seller --transport http \
  --header 'Authorization: Bearer <sellerToken>' --method tools/list

The buyer server is /s/<id>/mcp/buyer, with the buyerToken from POST /s/<id>/web/buyer (body {"displayName":"Ben","purchaseCode":"2580"}, same headers). Approvals arrive as elicitation requests (form, or URL mode for the pickup pass); clients without elicitation get approval_required and answer with confirm_action.

What's real and what's simulated

Tests and evals

pnpm test           # 236 tests: policy (property-based), receipts, settlement, UCP, Ring, ring-sim, verifier, agents, MCP end-to-end (incl. Tasks + my_items), the Alexa skill, hosted shops, Stoop Street, AgentCore
pnpm eval:redteam   # 300 adversarial conversations + 200 benign buyers -> evals/REPORT.md
pnpm eval:poh       # proof-of-handoff confusion matrix -> evals/POH_REPORT.md

End-to-end:

• The golden path runs through two real MCP clients: sweep → appraise → list → mandate → haggle → approve → UCP checkout → pass → doorbell → VERIFIED → paid.

• The scrutiny path covers:

  • 401/403/404 protocol hardening

  • an Alexa-style session-less client

  • the > $100 voice code

  • scam blocking and the two-buyer race

  • piracy, no-show, item still there, camera offline, and webhook replay

  • offer flooding (rate limited before any model call)

  • MCP Tasks: watch_handoff follows a sale to CLOSED, stays private to its owner, and can be cancelled

• Alexa+ design rules as a test (services/stack/test/design-rules.test.ts): every spoken line and approval prompt in a full sale (33 lines) is under 30 seconds (longest: 56 words), offers at most 5 options, and never speaks an id, JSON or a URL.

Browser QA and demo recording (needs pnpm demo running and Google Chrome; uses playwright-core, which never downloads a browser):

pnpm qa       # every judged surface at 1280x800 and 390 px: console/HTTP errors + screenshots
pnpm record   # the golden path as one .webm clip per surface, for the video

Simulated Ring events from the command line (local or deployed; always labelled simulator-signed):

pnpm ring-sim event button
pnpm ring-sim replay
pnpm ring-sim scenario golden

Fire TV (Garage Mode)

apps/firetv is Garage Mode: the household's sellable things on the big screen. Pick items with the remote's D-pad, press List selected, approve on screen, and Stoop lists them — the footer shows the live sale line through to "Sold". It's built on Amazon's react-native-multi-tv-app-sample (MIT-0) and is a real stateless MCP client to the same stack (it holds no money or address keys; it only proposes). It is a separate Yarn 4 workspace, so use corepack yarn:

pnpm --filter @stoop/stack start      # the stack on :8787
cd apps/firetv && corepack yarn install && corepack yarn dev:web   # open http://localhost:8082

See apps/firetv/README.md for details and the Android TV build.

Docs

• docs/ARCHITECTURE.md: components, protocols, truth table, local-vs-AWS mapping

• docs/AGENTS.md: agents, rules R1–R13, guidance for coding agents

• skills/stoop/SKILL.md: the Agent Skill for assistants using Stoop

• docs/AWS_BUILDER.md: AWS services, honest status per row

• docs/PRODUCT_FEEDBACK.md · docs/FRICTION_LOG.md

• docs/RING_CERT_NOTES.md · docs/AI_DISCLOSURE.md · docs/PLAN.md

• Open source:

  • packages/proof-of-handoff, published on npm as proof-of-handoff: verify any receipt with npx proof-of-handoff verify receipt.jws --jwks jwks.json

  • oss/ring-api-helloworld: a media-helpers contribution to Amazon's Ring starter, open upstream as AmazonAppDev/ring-api-helloworld#36 (issue #35)

Repo layout

packages/  shared · policy · proof-of-handoff · ui-cards
services/  settlement · ring-bridge · verifier · agents · mcp-server · stack
tools/     ring-sim (simulator-signed Ring webhooks)
apps/      alexa-sim · pass · ops · firetv (Garage Mode, Yarn 4)
evals/     red team + proof-of-handoff
oss/       ring-api-helloworld contribution
skills/    stoop/SKILL.md

License

MIT