diff --git a/docs/release-control/v6/internal/subsystems/frontend-primitives.md b/docs/release-control/v6/internal/subsystems/frontend-primitives.md
index 1971dc0d19..4e51acbce6 100644
--- a/docs/release-control/v6/internal/subsystems/frontend-primitives.md
+++ b/docs/release-control/v6/internal/subsystems/frontend-primitives.md
@@ -2426,6 +2426,12 @@ column chooser trigger, panel title, reset action, empty-state copy, hidden
 count badge, dropdown width, and outside-click lifecycle through the shared
 shell/state/model split. Table surfaces must compose that primitive instead of
 recreating local column chooser buttons or panels.
+Selection-card groups are registry-backed too. `SelectionCardGroup` owns the
+compact/detail card grid, active-card tone, disabled selection behavior,
+pressed-state semantics, title/description styling, and icon container
+treatment through the shared shell/state/model split. Settings and feature
+surfaces must compose that primitive instead of copying compact/detail
+border-card styling locally.
 Grouped/list table-mode controls are registry-backed as well.
 `GroupedTableModeSegmentedControl` owns the shared `Group by` label,
 `Grouped` / `List` labels, tooltip titles, and icons for table mode switching.
diff --git a/frontend-modern/scripts/shared-template-registry.json b/frontend-modern/scripts/shared-template-registry.json
index 399effaa3b..cc0169b7eb 100644
--- a/frontend-modern/scripts/shared-template-registry.json
+++ b/frontend-modern/scripts/shared-template-registry.json
@@ -273,6 +273,24 @@
         "scripts/shared-template-audit.mjs"
       ]
     },
+    {
+      "id": "selection-card-group-shell",
+      "category": "selection-card-group",
+      "summary": "Selectable settings card groups must compose SelectionCardGroup instead of recreating compact/detail active-card styling and disabled selection behavior locally.",
+      "canonical": {
+        "path": "src/components/shared/SelectionCardGroup.tsx",
+        "export": "SelectionCardGroup"
+      },
+      "requiredConsumers": [
+        { "path": "src/components/Settings/AISettingsDialogs.tsx" },
+        { "path": "src/components/Settings/UpdatesSettingsPanel.tsx" }
+      ],
+      "proof": [
+        "src/components/shared/SharedPrimitives.guardrails.test.ts",
+        "src/components/shared/SelectionCardGroup.test.tsx",
+        "scripts/shared-template-audit.mjs"
+      ]
+    },
     {
       "id": "grouped-table-mode-segmented-control",
       "category": "table-mode-control",
@@ -424,6 +442,27 @@
         "scripts/shared-template-audit.mjs"
       ]
     },
+    {
+      "id": "selection-card-group-local-active-card-styles",
+      "category": "selection-card-group",
+      "summary": "Settings and feature surfaces must not copy the compact/detail active-card styling owned by SelectionCardGroup.",
+      "canonical": {
+        "path": "src/components/shared/selectionCardGroupModel.ts",
+        "export": "getSelectionCardButtonClass"
+      },
+      "scopes": ["src/components/Settings", "src/features", "src/pages"],
+      "extensions": [".tsx"],
+      "allPatterns": [
+        "p-4 rounded-md border-2 transition-all text-left",
+        "p-3 rounded-md border-2 transition-all text-center"
+      ],
+      "legacyReason": "Retired migration debt. Selectable settings card groups must use SelectionCardGroup; local compact/detail active-card styling forks are not allowed.",
+      "allowedPaths": [],
+      "proof": [
+        "src/components/shared/SharedPrimitives.guardrails.test.ts",
+        "scripts/shared-template-audit.mjs"
+      ]
+    },
     {
       "id": "grouped-table-mode-local-segmented-control",
       "category": "table-mode-control",
diff --git a/frontend-modern/src/components/shared/SharedPrimitives.guardrails.test.ts b/frontend-modern/src/components/shared/SharedPrimitives.guardrails.test.ts
index fd0b50483a..d2340f2732 100644
--- a/frontend-modern/src/components/shared/SharedPrimitives.guardrails.test.ts
+++ b/frontend-modern/src/components/shared/SharedPrimitives.guardrails.test.ts
@@ -244,20 +244,74 @@ describe('shared primitive guardrails', () => {
   });
 
   it('routes selectable settings cards through SelectionCardGroup', () => {
+    const registry = JSON.parse(sharedTemplateRegistrySource) as {
+      rules?: Array<{
+        id: string;
+        canonical?: { path?: string; export?: string };
+        requiredConsumers?: Array<{ path?: string }>;
+      }>;
+      patternGuards?: Array<{
+        id: string;
+        canonical?: { path?: string; export?: string };
+        allPatterns?: string[];
+        scopes?: string[];
+        allowedPaths?: string[];
+      }>;
+    };
+    const registeredRule = registry.rules?.find(
+      (rule) => rule.id === 'selection-card-group-shell',
+    );
+    const registeredGuard = registry.patternGuards?.find(
+      (guard) => guard.id === 'selection-card-group-local-active-card-styles',
+    );
+
+    expect(registeredRule?.canonical?.path).toBe(
+      'src/components/shared/SelectionCardGroup.tsx',
+    );
+    expect(registeredRule?.canonical?.export).toBe('SelectionCardGroup');
+    expect(registeredRule?.requiredConsumers?.map((consumer) => consumer.path)).toEqual([
+      'src/components/Settings/AISettingsDialogs.tsx',
+      'src/components/Settings/UpdatesSettingsPanel.tsx',
+    ]);
+    expect(registeredGuard?.canonical?.path).toBe(
+      'src/components/shared/selectionCardGroupModel.ts',
+    );
+    expect(registeredGuard?.canonical?.export).toBe(
+      'getSelectionCardButtonClass',
+    );
+    expect(registeredGuard?.allPatterns).toEqual([
+      'p-4 rounded-md border-2 transition-all text-left',
+      'p-3 rounded-md border-2 transition-all text-center',
+    ]);
+    expect(registeredGuard?.allowedPaths ?? []).toHaveLength(0);
+    expect(registeredGuard?.scopes).toEqual(
+      expect.arrayContaining([
+        'src/components/Settings',
+        'src/features',
+        'src/pages',
+      ]),
+    );
+
     expect(selectionCardGroupSource).toContain('useSelectionCardGroupState');
     expect(selectionCardGroupSource).toContain('getSelectionCardGroupClass');
     expect(selectionCardGroupSource).toContain('getSelectionCardButtonClass');
     expect(selectionCardGroupSource).toContain('getSelectionCardTitleClass');
+    expect(selectionCardGroupSource).toContain('aria-pressed');
+    expect(selectionCardGroupSource).toContain('disabled={selectionCardGroup.isOptionDisabled');
     expect(selectionCardGroupSource).not.toContain('resolveSelectionCardTone');
     expect(selectionCardGroupSource).not.toContain('props.onChange(option.value)');
     expect(selectionCardGroupStateSource).toContain('export function useSelectionCardGroupState');
     expect(selectionCardGroupStateSource).toContain('createMemo');
     expect(selectionCardGroupStateSource).toContain('resolveSelectionCardTone');
+    expect(selectionCardGroupStateSource).toContain('props.disabled || option.disabled');
     expect(selectionCardGroupStateSource).toContain('props.onChange(option.value)');
     expect(selectionCardGroupModelSource).toContain('resolveSelectionCardGroupVariant');
     expect(selectionCardGroupModelSource).toContain('resolveSelectionCardTone');
     expect(selectionCardGroupModelSource).toContain('getSelectionCardButtonClass');
     expect(selectionCardGroupModelSource).toContain("compact: 'grid grid-cols-2 gap-2'");
+    expect(selectionCardGroupModelSource).toContain(
+      "detail: 'grid grid-cols-1 gap-3'",
+    );
     expect(aiSettingsDialogsSource).toContain('SelectionCardGroup');
     expect(aiSettingsDialogsSource).toContain('variant="compact"');
     expect(aiSettingsDialogsSource).not.toContain(