# Bonsai

- **Event:** [AI Engineer World's Fair Hackathon 2026](https://cerebralvalley.ai/e/aiewf-hackathon-2026)
- **When:** Jun 27 at 9:00 AM – Jun 28 at 5:00 PM (PDT)
- **Where:** San Francisco, CA
- **Team:** [Nicholas Allison](https://cerebralvalley.ai/u/knick)
- **GitHub:** https://github.com/enturesting/bonsai
- **Demo video:** https://youtu.be/AkhUHc4OgXo
- **Gallery:** https://cerebralvalley.ai/e/aiewf-hackathon-2026/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/aiewf-hackathon-2026/hackathon/gallery/11

Every domain expert who owns "what good looks like" — a compliance lead, a security reviewer — is drowning, hand-checking AI answers one at a time, and the ones that bite are the confident answers whose citation doesn't actually hold. Bonsai turns those experts into bonsai gardeners. They shape the ideal form once — a small, frozen standard — and the harness does the patient tending: it watches a cited-answer agent (Gemini 3.5 via Vertex AI), catches every claim whose citation doesn't trace to its source, clusters that failure by meaning (MongoDB Atlas $vectorSearch over Voyage embeddings), grows a new branch — one general check that catches that family of mistakes — and prunes the checks that overfit or go stale. Any real decision turns on dozens of factors; the rubric captures that accumulated judgment branch by branch, instead of one brittle hand-written test. And the growth stays honest: a build-time test fails CI if the loop ever reads the gardener's frozen standard (a guardrail, not an unbreakable wall). On that held-out set the loop can't read, agreement rose 9→14 of 15 (Wilson 95% CI [70.2%, 98.8%], sign-test p=0.031). The aim: one gardener, many trees.

---

Markdown version of https://cerebralvalley.ai/e/aiewf-hackathon-2026/hackathon/gallery/11. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt