REHASH
Built at The Persistent Context Sprint Hackathon | Live at MongoDB .Local Build Fest · Aug 13, 2026 · San Francisco, CA

Rehash remembers why past project ideas were rejected, not just that they were. When someone pitches a new idea, it pulls out the idea's core mechanic and likely flaw, turns that into an embedding, and checks it against every past rejection stored in MongoDB Atlas Vector Search. It matches on why something failed, not on how it's worded, so two ideas that look nothing alike can still get flagged for sharing the same underlying flaw. When it finds a match, it speaks the result back using two different ElevenLabs voices: one reacts live, the other reads the original rejection reason word for word, so the system's own memory is talking back to you. A human always makes the final call. Built for teams and hackathon judges who keep re-debating ideas that already failed for reasons nobody remembered.