diff --git a/desktop/src/shared/features/manifest.ts b/desktop/src/shared/features/manifest.ts
index 4335cf3a90..1e6f48ae01 100644
--- a/desktop/src/shared/features/manifest.ts
+++ b/desktop/src/shared/features/manifest.ts
@@ -13,6 +13,7 @@ const FeatureDefinitionSchema = z.object({
   id: z.string().min(1),
   name: z.string().min(1),
   description: z.string(),
+  defaultEnabled: z.boolean().optional(),
   platforms: z.array(FeaturePlatformSchema).optional(),
 });
 
diff --git a/desktop/src/shared/features/resolveEnabled.test.mjs b/desktop/src/shared/features/resolveEnabled.test.mjs
index 69414249dd..d725444870 100644
--- a/desktop/src/shared/features/resolveEnabled.test.mjs
+++ b/desktop/src/shared/features/resolveEnabled.test.mjs
@@ -12,6 +12,17 @@ describe("resolveEnabled (preview-only)", () => {
     assert.equal(resolveEnabled("workflows", { workflows: true }), true);
   });
 
+  it("uses an enabled manifest default when no override exists", () => {
+    assert.equal(resolveEnabled("workspaceRail", {}, true), true);
+  });
+
+  it("lets an explicit opt-out override an enabled default", () => {
+    assert.equal(
+      resolveEnabled("workspaceRail", { workspaceRail: false }, true),
+      false,
+    );
+  });
+
   it("returns false when user explicitly opts out", () => {
     assert.equal(resolveEnabled("workflows", { workflows: false }), false);
   });
diff --git a/desktop/src/shared/features/resolveEnabled.ts b/desktop/src/shared/features/resolveEnabled.ts
index 1b0e4665bb..e3c544ec50 100644
--- a/desktop/src/shared/features/resolveEnabled.ts
+++ b/desktop/src/shared/features/resolveEnabled.ts
@@ -7,11 +7,13 @@
  * (see `useFeatureEnabled`). Once you're inside `resolveEnabled`, the
  * feature IS in the manifest — preview by definition.
  *
- * Returns true only if the user has explicitly opted in via overrides.
+ * An explicit user override wins; otherwise the feature's manifest default is
+ * used (false when omitted).
  */
 export function resolveEnabled(
   featureId: string,
   overrides: Record<string, boolean>,
+  defaultEnabled = false,
 ): boolean {
-  return overrides[featureId] === true;
+  return overrides[featureId] ?? defaultEnabled;
 }
diff --git a/desktop/src/shared/features/types.ts b/desktop/src/shared/features/types.ts
index 266bae6f46..c452cd54b4 100644
--- a/desktop/src/shared/features/types.ts
+++ b/desktop/src/shared/features/types.ts
@@ -12,6 +12,8 @@ export interface FeatureDefinition {
   id: string;
   name: string;
   description: string;
+  /** Whether the preview is enabled when the user has not chosen an override */
+  defaultEnabled?: boolean;
   /** If omitted, feature is available on all platforms */
   platforms?: FeaturePlatform[];
 }
diff --git a/desktop/src/shared/features/useFeatureEnabled.ts b/desktop/src/shared/features/useFeatureEnabled.ts
index 6e928b3be3..b0c9878d0b 100644
--- a/desktop/src/shared/features/useFeatureEnabled.ts
+++ b/desktop/src/shared/features/useFeatureEnabled.ts
@@ -82,7 +82,7 @@ export function useFeatureSnapshot(): Record<string, boolean> {
  *
  * The manifest (`preview-features.json`) lists ONLY preview features:
  *
- * - in manifest (preview): true only if the user opted in via overrides
+ * - in manifest (preview): explicit user override, then manifest default (off if omitted)
  * - NOT in manifest (stable): always true (fail-open)
  *
  * Membership in the manifest signals "this needs gating"; absence means
@@ -102,7 +102,7 @@ export function useFeatureEnabled(featureId: string): boolean {
     return true;
   }
 
-  return resolveEnabled(featureId, overrides);
+  return resolveEnabled(featureId, overrides, feature.defaultEnabled);
 }
 
 /**
diff --git a/preview-features.json b/preview-features.json
index d7362197e6..33cc7a252c 100644
--- a/preview-features.json
+++ b/preview-features.json
@@ -28,6 +28,7 @@
     {
       "id": "workspaceRail",
       "name": "Community Rail",
+      "defaultEnabled": true,
       "description": "Far-left rail for switching communities with cross-community unread indicators",
       "platforms": [
         "desktop"