When designing client-facing interfaces (request payloads, component props, or render-slot “host action” APIs), treat optional features and host-provided children as contracts—not assumptions. Apply these rules: 1) Capability-gate request fields: Only send optional parameters when the server/daemon advertises support. Keep gating consistent across all call sites. 2) Don’t rely on opaque host forwarding: If your component needs to identify/trigger host actions after re-parenting (e.g., overflow menu), don’t depend on injected props/selectors being forwarded by arbitrary ReactNodes. Use wrappers, structured action descriptors (id/label/callback), or require/tightly type a forwarding contract (documented + enforced). 3) Keep shared state props consistent: If sibling controls are disabled/enabled based on the same state (e.g., approval pending), pass the computed value through—avoid hardcoded props. 4) Make UX fallbacks explicit: Avoid hardcoded non-localized labels and ensure accessible naming is produced from contract inputs (e.g., prefer `aria-label`/`title`, and don’t create unlabeled menu items from icon-only children). Example (capability-gated request param): ```ts const params: any = { pageSize: SESSION_LIST_PAGE_SIZE, archiveState: 'active', }; if (capabilities.session_source_metadata) { params.sourceType = WEB_SHELL_SESSION_SOURCE_TYPE; } await listWorkspaceSessions(params); ``` Example (avoid opaque render-slot assumptions—use descriptors instead of ReactNode host actions): ```ts type PaneAction = { id: string; label: string; onSelect: () => void }; function PaneHeaderActions({ actions }: { actions: PaneAction[] }) { return ( {actions.map(a => ( {a.label} ))} ); } ```