Initial approach. The BRD's atomic unit was a "call." Every dashboard, list, and report was built around it.
Where it broke. During stakeholder clarification the scope expanded: Claralens has to grade SMS, WhatsApp, and email too — not just voice. "Call" quietly excludes three of the four channels, and any IA built on it would need re-architecting the moment text channels arrived.
Resolution. Renamed the atomic unit to Interaction (channel: voice | sms | whatsapp | email; actor: human | bot). Every surface became a lens over one interaction corpus. Evidence anchoring got two renderers behind one contract — timestamp for voice, message ID for text — so adding a channel never means adding an app.
