# Felipe M Affonso

- **Event:** [Built with Opus 4.7: a Claude Code hackathon](https://cerebralvalley.ai/e/built-with-4-7-hackathon)
- **When:** Apr 21 at 12:00 PM – Apr 27 at 2:00 AM (EDT)
- **Where:** Online
- **Team:** [Felipe Affonso](https://cerebralvalley.ai/u/felipemaffonso)
- **GitHub:** https://github.com/FelipeMAffonso/lens
- **Demo video:** https://www.youtube.com/watch?v=Rh4eufbcD3I
- **Gallery:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery/245

Lens is an open-source consumer welfare agent for the AI shopping era. Paste any AI shopping answer (from ChatGPT, Claude, Gemini, Perplexity, or Rufus), drop in a retailer URL, or shop with the Chrome extension running, and Lens audits the recommendation in real time. It flags every confabulated spec the AI cited (the "stainless-steel housing" that's actually plastic, the "15-bar pressure" that's a marketing number), surfaces the spec-optimal product the AI skipped, names dark patterns at checkout (preselected fees, drip pricing, fake scarcity, forced continuity) with the FTC junk-fee rule cited inline, and drafts the refund or complaint letter for your one-click approval.

After you buy, the watchers keep working. CPSC and NHTSA recalls, retailer price-drop windows, subscription pre-charges, and firmware CVEs cross-match against your purchases, and Lens drafts the intervention before you ask.

One Cloudflare Worker powers a web app, a Chrome MV3 extension, a mobile PWA, an MCP server with 16 tools callable from Claude Desktop, and a public OpenAPI surface. The deterministic ranker stays language-model-free once your utility function is formed, so the top pick is reproducible from the utility function. MIT licensed, no affiliate links, $0 affiliate revenue. Built with Opus 4.7. Live at https://lens-b1h.pages.dev.

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Markdown version of https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery/245. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt