Your AI tells a store what you need, without telling it who you are. The store answers with an offer priced inside rules a human locked, and every promotional claim is checked before it can exist. Neither side accumulates a profile of the other.
Live:hemloop.app · Built for the OpenAI WebMCP Challenge.
| Route | What it is |
|---|---|
Hemloop/ | Both sides of one request in one shared space. Registers all 21 WebMCP tools (9 closet + 12 studio). Three human gates: Approve next request, Approve offer, Bought. |
Closet/closet | Full shopper surface (Wardrobe · Requests and offers). Nine tools. Wardrobe rows never leave the page. |
Studio/studio | Full merchant surface (Demand · Offer and rules · Composition). Twelve tools. Lock facts and approve proposals are human-only. |
Docs/docs/ | Product docs: the loop, the problem, WebMCP, quick start, use cases. |
/merchant redirects to /studio?tab=demand.
Host:hemloop.app. The app deploys to Cloudflare Workers (wrangler) or Vercel and runs the same way on either.
Supported browsers:
- ChatGPT’s desktop-app built-in browser — open one of the hosts above inside ChatGPT; WebMCP tools register automatically.
- Chrome with
chrome://flags/#enable-webmcp-testingenabled — flip the flag, press Relaunch, then reopen the host. (Chrome 149+ may already carry the origin-trial token for these hosts.)
The header should show tools live. Amber preview means the runtime is not exposed in that browser. The iOS in-app browser shows the page with tools in preview.
No account. State lives in your browser (localStorage); an incognito window is a clean install.
- Open a supported host in a supported browser (above).
- Upload a sample receipt image from
public/receipts/(northlight-till-receipt.pngorharborview-order-email.png) in the chat with the prompt Use Hemloop's import_receipt site tool now. I approve importing this exact receipt into my private Hemloop closet. Do not only summarize it or claim success; call the tool with the receipt. - Ask: Use Hemloop's find_gaps site tool now, then tell me: What should I buy next? (
find_gaps). - Ask: Use Hemloop's report_demand_gap site tool now. Tell the store I need hoodie, size M It is refused (
human-approval-required). Press Approve next request, then reply Yes, send it now with Hemloop's report_demand_gap site tool. Tell the store I need hoodie, size M One press releases one event; a third send is refused again. - Ask: Use Hemloop's get_demand and propose_offer site tools now. Which store can fill this, and what can it offer inside its rules? Press Approve offer.
- Ask: Use Hemloop's get_offers site tool now. Are there any offers for me? Press Bought.
Every station card carries its exact prompt under Say this with a Copy button; the prompts name the tool so the agent calls it instead of answering from memory.
Full walkthrough: docs/USER-GUIDE.md · docs/05-quick-start.md.
| Surface | Tool | Kind | What it does | Structural guarantee |
|---|---|---|---|---|
| Closet | get_wardrobe | read | Compact wardrobe rows on this page | readOnlyHint, untrustedContentHint; no shopper id |
| Closet | get_my_sizes | read | Sizes owned, optional brand filter | readOnlyHint |
| Closet | find_gaps | read | Missing / thin categories; worn-out by purchase date | readOnlyHint; due rows carry date, months, size only |
| Closet | check_fit | read | Size advice from owned garments vs catalog | readOnlyHint |
| Closet | get_preferences | read | Fit, colour, materials, ceiling, brands | readOnlyHint; fields only if sharing level allows |
| Closet | add_garment | write | Add one local wardrobe row | Enum + bounds; never leaves the page |
| Closet | report_demand_gap | write | Only outbound path to a merchant | Needs human approval; one press → one event; no shopper id |
| Closet | import_receipt | write | Parse receipt / order email into local purchases | Parsed locally; nothing leaves the page |
| Closet | get_offers | read | Approved offers for this closet’s own requests | readOnlyHint; Bought / Passed is human-only |
| Studio | get_campaign_state | read | Facts, lock state, brief, scenes, format | readOnlyHint |
| Studio | set_brief | write | Creative brief (not rendered copy) | Brief cannot become a claim |
| Studio | add_scene / update_scene | write | Scene copy | Claim-validated before apply; reject atomically |
| Studio | reorder_scenes | write | Timeline order | Permutation-checked |
| Studio | seek_preview | write | Preview playhead | Clamped; deterministic |
| Studio | validate_claims | read | Dry-run claim validator | Never mutates |
| Studio | export_composition | read | Deliver HTML to the page | Refuses while any violation stands |
| Studio | get_offer | read | Locked offer (or one approved personal offer) | readOnlyHint; human-locked facts only |
| Studio | import_product | write | Pull a catalog product into unlocked facts | Refuses while facts are locked |
| Studio | get_demand | read | Incoming requests grouped and scored vs stock | readOnlyHint, untrustedContentHint |
| Studio | propose_offer | write | Stage a personal offer inside locked rules | Staged only; Approve is human-only |
Absent by design (no tool exists): approve_next_request, approve_offer, mark_bought, lock_facts, set_sharing_level.
git clone https://github.com/marconvm/hemloop
cd hemloop
npm install
npm run devNode 22+. App routes: /, /closet, /studio, /docs/. Tests: npm test. Lint: npm run lint.
Deploy (Cloudflare Workers): npm run build then npm run prepare:worker and npm run deploy:worker (see project scripts).
MIT · Copyright © 2026 Marco Cheung.
Wardrobe product photos are real retail catalog images, used with permission; the sources are listed in docs/PHOTO-CREDITS.md. The five merchants and their campaigns are fictional.