Feature toggles beat hard-coded agent IDs
Multi-agent shells rot when every new assistant becomes an if-else on agent ids. Microcopy forks. Export prefixes fork. Access checks fork. Soon the SPA is a customer-specific catalog pretending to be a product.
Default-open with overlays. Product feature flags gate shared UX. Per-agent overlay rows carry scope, starters, export prefixes, and access arrays. The SPA never parses JWTs to invent policy. White-label cores stay clean because domain agents are data, not code forks. Test matrices expand by flag, not by customer branch.
Figure 1. Shared shell UX is a product feature. Agent differences belong in overlay flags the API already authorizes. Source: Microsoft Learn: manage feature flags.
Figure 2. Feature flags gate surfaces. App roles still decide what the catalog may show. The SPA should not invent policy from JWTs. Source: Microsoft Learn: manage feature flags.