Security is architectural, not bolted on: hard tenant isolation, per-fact permissions, encrypted data in transit and at rest, scoped bearer tokens, agent limits with receipts and undo, and no training on your data.
The important properties are structural. Your company's brain is isolated per tenant, every fact carries the permissions of its source, and everything Heidi does is logged with evidence, so security failures cannot hide.
The deep dive on isolation is at falkster.ai/answers/tenant-isolation. For anything a security review needs beyond the site, ask through the waitlist form and you get the real documents, not marketing.