Interlock: Aditi Kumari, Austin Zhao, Arnav Sacheti, Shun-Hsun Liang.

Two companies, two private playbooks, one signed joint procedure. Neither side reads the other's. Interlock merges them on MongoDB Atlas: Vector Search aligns the steps, deterministic code checks the join, people are asked only where a rule can't decide, and both sign a certificate. Each company gets back its own slice with the partner as one sealed box. A refused handoff triggers self-repair through a change stream. When a rule changes, $graphLookup over the derivation index rebuilds only what was built from it.