diff --git a/src/components/admin/ai-quality-section.tsx b/src/components/admin/ai-quality-section.tsx
index 4a026e59f..ddcd6473f 100644
--- a/src/components/admin/ai-quality-section.tsx
+++ b/src/components/admin/ai-quality-section.tsx
@@ -65,64 +65,56 @@ export function AiQualitySection() {
     },
   });
 
-  if (query.isLoading) {
-    return (
-      <div className="bg-card border-border flex items-center gap-2 rounded-xl border p-4 sm:p-6">
-        <Loader2 className="h-4 w-4 animate-spin motion-reduce:animate-none" />
-        <span className="text-muted-foreground text-sm">
-          {t("admin.aiQuality.loading")}
-        </span>
-      </div>
-    );
-  }
-
-  if (query.isError) {
-    return (
-      <div
-        role="alert"
-        className="text-destructive bg-destructive/10 border-destructive/30 rounded-xl border p-4 text-sm"
-      >
-        {t("admin.aiQuality.loadError")}
-      </div>
-    );
-  }
-
-  const summary = query.data;
-
-  if (!summary || summary.buckets.length === 0) {
-    return (
-      <div className="bg-card border-border rounded-xl border p-4 sm:p-6">
-        <SettingsCardHeader
-          icon={Sparkles}
-          title={t("admin.aiQuality.title")}
-        />
-        <p className="text-muted-foreground mt-3 pl-7 text-sm">
-          {t("admin.aiQuality.empty")}
-        </p>
-      </div>
-    );
-  }
+  const summary = query.data ?? null;
+  const buckets = summary?.buckets ?? [];
+  const hasData = !!summary && buckets.length > 0;
 
+  // v1.18.1 — keep the outer card + header rendered across every query
+  // state (loading / error / empty / data) so the heading baseline stays at
+  // a constant Y-offset and the section never snaps downward when the data
+  // resolves. Mirrors <CoachFeedbackSection> (header outside the
+  // fetch-state branch).
   return (
     <div className="bg-card border-border space-y-4 rounded-xl border p-4 sm:p-6">
       <SettingsCardHeader
         icon={Sparkles}
         title={t("admin.aiQuality.title")}
         status={
-          <p className="text-muted-foreground text-xs">
-            {t("admin.aiQuality.windowLabel", {
-              days: String(summary.windowDays),
-            })}
-            {" · "}
-            {t("admin.aiQuality.generatedAtLabel")}{" "}
-            {fmt.dateTime(summary.generatedAt)}
-          </p>
+          hasData && summary ? (
+            <p className="text-muted-foreground text-xs">
+              {t("admin.aiQuality.windowLabel", {
+                days: String(summary.windowDays),
+              })}
+              {" · "}
+              {t("admin.aiQuality.generatedAtLabel")}{" "}
+              {fmt.dateTime(summary.generatedAt)}
+            </p>
+          ) : null
         }
       />
 
-      <div className="overflow-x-auto">
-        <table className="w-full text-sm" data-slot="ai-quality-table">
-          <thead>
+      {query.isLoading ? (
+        <div className="flex items-center gap-2">
+          <Loader2 className="h-4 w-4 animate-spin motion-reduce:animate-none" />
+          <span className="text-muted-foreground text-sm">
+            {t("admin.aiQuality.loading")}
+          </span>
+        </div>
+      ) : query.isError ? (
+        <div
+          role="alert"
+          className="text-destructive bg-destructive/10 border-destructive/30 rounded-md border p-3 text-sm"
+        >
+          {t("admin.aiQuality.loadError")}
+        </div>
+      ) : !hasData ? (
+        <p className="text-muted-foreground text-sm">
+          {t("admin.aiQuality.empty")}
+        </p>
+      ) : (
+        <div className="overflow-x-auto">
+          <table className="w-full text-sm" data-slot="ai-quality-table">
+            <thead>
             <tr className="text-muted-foreground border-border border-b text-left text-xs tracking-wider uppercase">
               <th className="py-2 pr-3 font-medium">
                 {t("admin.aiQuality.colSeverity")}
@@ -148,7 +140,7 @@ export function AiQualitySection() {
             </tr>
           </thead>
           <tbody>
-            {summary.buckets.map((bucket, idx) => {
+            {buckets.map((bucket, idx) => {
               const ratePct = Math.round(bucket.helpfulRate * 100);
               return (
                 <tr
@@ -184,7 +176,8 @@ export function AiQualitySection() {
             })}
           </tbody>
         </table>
-      </div>
+        </div>
+      )}
     </div>
   );
 }
diff --git a/src/components/settings/ai/disable-coach-card.tsx b/src/components/settings/ai/disable-coach-card.tsx
index 4a1f8687a..9e1339768 100644
--- a/src/components/settings/ai/disable-coach-card.tsx
+++ b/src/components/settings/ai/disable-coach-card.tsx
@@ -3,6 +3,10 @@
 /**
  * v1.4.47 W3 — Coach activation toggle card.
  *
+ * v1.18.0 (S5) — moved out of Settings → AI into the dedicated Coach
+ * section; its `<section>` id namespace is `settings-coach-activate-*`
+ * accordingly. (The file path stays under `ai/` as pre-existing drift.)
+ *
  * v1.18.1 (D7) — polarity flip. The card now reads "Activate Coach" with the
  * Switch ON by default (the Coach is on for everyone unless the user opts
  * out). The persisted state is still the single `User.disableCoach` field —
@@ -137,14 +141,14 @@ export function DisableCoachCard({
 
   return (
     <section
-      aria-labelledby="settings-ai-disable-coach-title"
+      aria-labelledby="settings-coach-activate-title"
       data-testid="settings-disable-coach-card"
       className="bg-card border-border rounded-xl border p-4 sm:p-6"
     >
       <SettingsCardHeader
         icon={MessageCircleHeart}
         title={t("settings.coach.activate.title")}
-        titleId="settings-ai-disable-coach-title"
+        titleId="settings-coach-activate-title"
         description={t("settings.coach.activate.description")}
         status={
           <Switch
diff --git a/src/components/settings/integrations/connections-panel.tsx b/src/components/settings/integrations/connections-panel.tsx
index d7ec368fc..48a45ce2e 100644
--- a/src/components/settings/integrations/connections-panel.tsx
+++ b/src/components/settings/integrations/connections-panel.tsx
@@ -242,10 +242,6 @@ export function ConnectionsPanel() {
 
   return (
     <div className="space-y-6" data-slot="connections-panel">
-      <p className="text-muted-foreground text-sm">
-        {t("settings.sections.integrations.connections.description")}
-      </p>
-
       <WithingsCard viewModel={withingsViewModel} />
       <WhoopCard viewModel={whoopViewModel} />
       <FitbitCard viewModel={fitbitViewModel} />
diff --git a/src/components/settings/integrations/notification-channels-panel.tsx b/src/components/settings/integrations/notification-channels-panel.tsx
index 0faf9a4a8..192b0442c 100644
--- a/src/components/settings/integrations/notification-channels-panel.tsx
+++ b/src/components/settings/integrations/notification-channels-panel.tsx
@@ -18,7 +18,6 @@
 import { useQuery } from "@tanstack/react-query";
 
 import { useAuth } from "@/hooks/use-auth";
-import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import { NotificationStatusCard } from "@/components/settings/notification-status-card";
 import { NtfyCard } from "@/components/settings/ntfy-card";
@@ -37,7 +36,6 @@ interface GlobalServiceAvailability {
 }
 
 export function NotificationChannelsPanel() {
-  const { t } = useTranslations();
   const { isAuthenticated } = useAuth();
 
   const { data: globalServices } = useQuery({
@@ -54,10 +52,6 @@ export function NotificationChannelsPanel() {
 
   return (
     <div className="space-y-6" data-slot="notification-channels-panel">
-      <p className="text-muted-foreground text-sm">
-        {t("settings.sections.integrations.channels.description")}
-      </p>
-
       <NotificationStatusCard />
 
       {/* v1.4.27 MB3 — `scroll-mt-28` keeps each channel card's anchor
diff --git a/src/components/settings/medications-section.tsx b/src/components/settings/medications-section.tsx
index 54abf90c7..c19d5c261 100644
--- a/src/components/settings/medications-section.tsx
+++ b/src/components/settings/medications-section.tsx
@@ -19,9 +19,11 @@ import { useMedicationListLayout } from "@/lib/queries/use-medication-list-layou
 
 /**
  * v1.16.10 — the "Medikamente" settings section. v1.18.0 (S5) promoted it
- * from a Layout-hub child to its own standalone nav entry (always shown —
- * medications is a CORE domain) and gathered the medication-specific
- * preferences here. Hosts three blocks:
+ * from a Layout-hub child to its own standalone nav entry and gathered the
+ * medication-specific preferences here. v1.18.1 (D3) made medications a
+ * toggleable fail-open module, so this nav entry hides when the account
+ * turns the module off (the medication data routes stay live). Hosts three
+ * blocks:
  *   1. The list VIEW preference — cards vs table, written optimistically
  *      through the same `PUT /api/medications/layout` the page header
  *      toggle uses (the toggle component is shared).
diff --git a/src/components/settings/notifications-section.tsx b/src/components/settings/notifications-section.tsx
index 82a06fbb4..ff979d0c5 100644
--- a/src/components/settings/notifications-section.tsx
+++ b/src/components/settings/notifications-section.tsx
@@ -17,9 +17,9 @@ import { MoodReminderCard } from "@/components/settings/mood-reminder-card";
  *
  * Each reminder-type card is shown ONLY when its module is enabled, read from
  * the resolved `useAuth().user.modules` map (the same `/auth/me` map nav and
- * Insights pills gate off). Mood → `mood`, Coach nudge → `coach`. Low-stock
- * runway maps to medications, which fails open (a missing key reads as
- * enabled) so a stale `/me` payload never blanks a card.
+ * Insights pills gate off). Mood → `mood`, Coach nudge → `coach`, low-stock
+ * runway → `medications` (a toggleable fail-open module since D3, so a missing
+ * key reads as enabled and a stale `/me` payload never blanks a card).
  *
  * v1.18.1 (D5) — the page is intentionally lean: the section blurb, the
  * channels / inbox cross-links, and the embedded Vorsorge (preventive-care)
@@ -35,6 +35,7 @@ export function NotificationsSection() {
   // so a stale `/me` payload without the module map keeps every card visible.
   const moodEnabled = user?.modules?.mood !== false;
   const coachEnabled = user?.modules?.coach !== false;
+  const medsEnabled = user?.modules?.medications !== false;
 
   return (
     <section
@@ -61,11 +62,13 @@ export function NotificationsSection() {
         </div>
       ) : null}
 
-      {/* Medication low-stock runway — medications is a CORE domain, so this
-          is always shown. */}
-      <div id="low-stock" className="scroll-mt-28">
-        <LowStockCard isAuthenticated={isAuthenticated} />
-      </div>
+      {/* Medication low-stock runway — only when the medications module is
+          enabled (toggleable, fail-open, since D3). */}
+      {medsEnabled ? (
+        <div id="low-stock" className="scroll-mt-28">
+          <LowStockCard isAuthenticated={isAuthenticated} />
+        </div>
+      ) : null}
 
       {/* Proactive Coach nudge — only when the coach module is enabled. */}
       {coachEnabled ? (
diff --git a/src/components/settings/sources-section.tsx b/src/components/settings/sources-section.tsx
index d9ce95c3d..077b6de04 100644
--- a/src/components/settings/sources-section.tsx
+++ b/src/components/settings/sources-section.tsx
@@ -111,31 +111,16 @@ const DEVICE_TYPE_LABEL_KEYS: Record<DeviceType, string> = {
   unknown: "settings.sections.sources.deviceLabels.unknown",
 };
 
-export interface SourcesSectionProps {
-  /**
-   * `"standalone"` (the default) renders the full page header + the
-   * cross-link back to Integrations — the shape used while Sources had its
-   * own `/settings/sources` route. `"subtab"` (v1.18.0 S3) suppresses both:
-   * Sources now renders inside the Integrations → Sources sub-tab, so the
-   * page header is the parent section's and a cross-link back to the page
-   * that already contains it would be circular.
-   */
-  variant?: "standalone" | "subtab";
-}
-
 /**
  * `<SourcesSection>` — the per-metric source-priority + device-type ladders.
  *
  * v1.18.1 (D4) — Sources is a standalone `/settings/sources` left-side entry
- * again (split back out of the Integrations sub-tabs). The default
- * `variant="standalone"` renders the section header + the cross-link back to
- * Integrationen; `variant="subtab"` is retained for any embedded use and
- * suppresses the header.
+ * again (split back out of the Integrations sub-tabs). It renders its own
+ * section header + the cross-link back to Integrationen.
  */
-export function SourcesSection({ variant = "standalone" }: SourcesSectionProps = {}) {
+export function SourcesSection() {
   const { t } = useTranslations();
   const queryClient = useQueryClient();
-  const isSubtab = variant === "subtab";
 
   const { data: remote, isLoading } = useQuery({
     queryKey: queryKeys.sourcePriority(),
@@ -298,27 +283,25 @@ export function SourcesSection({ variant = "standalone" }: SourcesSectionProps =
       aria-labelledby="settings-section-sources-title"
       className="space-y-6"
     >
-      {isSubtab ? null : (
-        // v1.18.1 (D0/D4) — standalone left-side entry again. The section
-        // blurb is dropped for consistent top alignment; the cross-link back
-        // to Integrationen (where the sources this ladder ranks are added /
-        // removed) stays as a quiet pointer.
-        <header>
-          <h1 id="settings-section-sources-title" className="sr-only">
-            {t("settings.sections.sources.title")}
-          </h1>
-          <p className="text-muted-foreground text-xs">
-            {t("settings.sections.sources.integrationsHint")}{" "}
-            <Link
-              href="/settings/integrations"
-              className="text-primary underline underline-offset-2"
-              data-slot="sources-integrations-cross-link"
-            >
-              {t("settings.sections.sources.integrationsHintLink")}
-            </Link>
-          </p>
-        </header>
-      )}
+      {/* v1.18.1 (D0/D4) — standalone left-side entry again. The section
+          blurb is dropped for consistent top alignment; the cross-link back
+          to Integrationen (where the sources this ladder ranks are added /
+          removed) stays as a quiet pointer. */}
+      <header>
+        <h1 id="settings-section-sources-title" className="sr-only">
+          {t("settings.sections.sources.title")}
+        </h1>
+        <p className="text-muted-foreground text-xs">
+          {t("settings.sections.sources.integrationsHint")}{" "}
+          <Link
+            href="/settings/integrations"
+            className="text-primary underline underline-offset-2"
+            data-slot="sources-integrations-cross-link"
+          >
+            {t("settings.sections.sources.integrationsHintLink")}
+          </Link>
+        </p>
+      </header>
 
       <div className="bg-card border-border space-y-4 rounded-xl border p-4 sm:p-6">
         <SettingsCardHeader
diff --git a/src/lib/modules/registry.ts b/src/lib/modules/registry.ts
index 1cf57e8a7..90f276002 100644
--- a/src/lib/modules/registry.ts
+++ b/src/lib/modules/registry.ts
@@ -10,11 +10,12 @@
  *
  * Two classes of domain:
  *
- *   - CORE (always-on): weight, blood pressure, pulse, medications — the
- *     measurement engine + meds. These are NOT in `MODULE_KEYS` and have
- *     NO registry entry. They can never be disabled; the gate has no key
- *     to flip and the write endpoint refuses them. This is structural,
- *     not a runtime check future code can soften.
+ *   - CORE (always-on): weight, blood pressure, pulse — the measurement
+ *     engine. These are NOT in `MODULE_KEYS` and have NO registry entry.
+ *     They can never be disabled; the gate has no key to flip and the
+ *     write endpoint refuses them. This is structural, not a runtime check
+ *     future code can soften. (Medications was CORE through v1.18.0; D3
+ *     graduated it to a fail-open toggleable module below.)
  *
  *   - TOGGLEABLE (the "secondary domains"): the maintainer-chosen scope
  *     below. Each carries a stable key, an i18n label + description key,
@@ -118,11 +119,12 @@ export const MODULE_KEYS = [
 export type ModuleKey = (typeof MODULE_KEYS)[number];
 
 /**
- * CORE domains — the always-on measurement engine + medications. Listed
- * here for documentation + the write-endpoint denylist; they have NO
- * `ModuleDefinition` and can never appear as a toggle. A crafted
- * `{ "weight": false }` blob is inert: `weight` is not a `ModuleKey`, so
- * the gate never reads it and the PATCH validator rejects it.
+ * CORE domains — the always-on measurement engine (weight / blood pressure
+ * / pulse). Listed here for documentation + the write-endpoint denylist;
+ * they have NO `ModuleDefinition` and can never appear as a toggle. A
+ * crafted `{ "weight": false }` blob is inert: `weight` is not a
+ * `ModuleKey`, so the gate never reads it and the PATCH validator rejects
+ * it. (Medications is a toggleable module since D3 — see `MODULE_KEYS`.)
  */
 export const CORE_DOMAIN_KEYS = [
   "weight",