Modality Complexity
Why it's a first-class dimension. "The more modalities being supported in parallel, the more the complexity increases. Inter-dependence across modalities may introduce further complexity." (source.cdp-recommendation-agent-md)
The dimensions of modality cost.
- Latency budget per modality. Web and mobile expect Inter-page; email tolerates Intra-day; POS often sits at Inter-session.
- Identity context. Browser cookies, mobile device IDs, email addresses, phone numbers — each modality has its own native identifier; reconciliation is non-trivial.
- Governance regime. Email and SMS are tightly regulated (CAN-SPAM, TCPA, GDPR Art. 7); web and mobile are looser; POS has its own PCI considerations.
- Cross-modality consistency. When the same activation must surface across modalities (see use-case.coupon-mobile-pos-sync), the architecture must reconcile their latency budgets — a design-time cost, not a runtime patch.
The agent's job. Elicit the modality count and inter-dependencies before recommending architecture. Single-modality (web-only, email-only) recommendations are vastly simpler than 3+ modality recommendations with required cross-modality consistency.
Frame for the customer. "Each additional modality you require with consistent activation roughly doubles the integration complexity of the platform you'll need to operate."