Memory items 4 and 5: two workspaces per agent and one fleet workspace for untrusted notes; the private ceiling, secret sessions never synced; trusted memory writes mirrored as conclusions; the agent's peer not observed; no rebuild, corrections by contra-fact or deleting our own conclusion; the fleet workspace always untrusted. Recorded in docs/decisions.md. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>