Wendy Device Interop

wendy-agent's prime directive against the SaaS stack: apply a change only when it carries a valid operator signature the device can verify itself. Cloud is a queue, never an authority — it can accept, append, relay, and enforce, but it holds no key that lets it originate an authoritative change (§5.3, D3). Everything below flows from that one rule.

Hard Rules

• Poll-only. The device polls cloud's postbox for changes; it never accepts a pushed change. There is no code path where cloud calls the device to mutate its state (§5.3).
• Device presents its own mTLS cert. To cloud (postbox poll) and to wendy-proxy (image pull) alike, the device authenticates with its own hardware-backed certificate. Cloud never holds a certificate of its own to act as a principal (§5.3, §5.7).
• No registry credential or token ever on-device. Images come only through wendy-proxy; the device never talks to a registry directly and never stores a pull credential (§5.7).
• Independent verifiability. Nothing is applied on the strength of "cloud said so." Every change must be independently checkable by the device: valid operator signature, current freshness, and binding to this device — see references/postbox-verification.md for the full checklist.

Fail-Safe Catalogue