diff --git a/apps/desktop/src/settings/DesktopClientSettings.test.ts b/apps/desktop/src/settings/DesktopClientSettings.test.ts
index 1ab9b3159e1f9..df35a07fe80e2 100644
--- a/apps/desktop/src/settings/DesktopClientSettings.test.ts
+++ b/apps/desktop/src/settings/DesktopClientSettings.test.ts
@@ -63,6 +63,7 @@ const clientSettings: ClientSettings = {
   sidebarThreadSortOrder: "created_at",
   boringSidebarEnabled: false,
   boringSidebarMultilineRows: false,
+  sidebarThreadRowLines: "two",
   threadDetailsUsageEnabled: false,
   threadDetailsItems: {},
   sidebarWorkingShelfEnabled: false,
diff --git a/apps/web/src/components/Sidebar.logic.test.ts b/apps/web/src/components/Sidebar.logic.test.ts
index 0e3f47b7f9ed8..a7b4765f739f9 100644
--- a/apps/web/src/components/Sidebar.logic.test.ts
+++ b/apps/web/src/components/Sidebar.logic.test.ts
@@ -33,6 +33,7 @@ import {
   resolveSidebarDropVerb,
   groupSidebarThreadsByProject,
   resolveSidebarFolderDot,
+  resolveSidebarRowLines,
   sidebarFolderExpansionKeys,
 } from "./Sidebar.logic";
 import { scopeThreadRef, scopedThreadKey } from "@t3tools/client-runtime/environment";
@@ -1641,6 +1642,33 @@ describe("resolveSidebarFolderDot", () => {
   });
 });
 
+describe("resolveSidebarRowLines", () => {
+  it.each([
+    // Automatic keeps cards outside folders and the retired switch inside them.
+    { setting: "automatic", section: "active", nested: false, multiline: true, lines: 3 },
+    { setting: "automatic", section: "pinned", nested: false, multiline: false, lines: 3 },
+    { setting: "automatic", section: "active", nested: true, multiline: false, lines: 1 },
+    { setting: "automatic", section: "active", nested: true, multiline: true, lines: 2 },
+    // An explicit pick overrides the retired switch, in and out of folders.
+    { setting: "one", section: "working", nested: false, multiline: true, lines: 1 },
+    { setting: "two", section: "pinned", nested: false, multiline: false, lines: 2 },
+    { setting: "one", section: "active", nested: true, multiline: true, lines: 1 },
+    { setting: "three", section: "active", nested: true, multiline: false, lines: 3 },
+    // Snoozed and Settled stay on one line whatever the setting.
+    { setting: "three", section: "snoozed", nested: false, multiline: false, lines: 1 },
+    { setting: "automatic", section: "settled", nested: false, multiline: true, lines: 1 },
+  ] as const)("$setting $section nested=$nested multiline=$multiline → $lines", (row) => {
+    expect(
+      resolveSidebarRowLines({
+        setting: row.setting,
+        section: row.section,
+        nested: row.nested,
+        folderRowsMultiline: row.multiline,
+      }),
+    ).toBe(row.lines);
+  });
+});
+
 describe("shouldCreateNewThreadInCurrentProject", () => {
   it("opens the picker when several projects are open, or only archived ones exist", () => {
     expect(shouldCreateNewThreadInCurrentProject(false, 2, 3)).toBe(false);
diff --git a/apps/web/src/components/Sidebar.logic.ts b/apps/web/src/components/Sidebar.logic.ts
index 5ed1320b59e55..e8c4222903312 100644
--- a/apps/web/src/components/Sidebar.logic.ts
+++ b/apps/web/src/components/Sidebar.logic.ts
@@ -24,7 +24,11 @@ import {
   type ScopedThreadRef,
   type ThreadId,
 } from "@t3tools/contracts";
-import type { SidebarProjectSortOrder, SidebarThreadSortOrder } from "@t3tools/contracts/settings";
+import type {
+  SidebarProjectSortOrder,
+  SidebarThreadRowLines,
+  SidebarThreadSortOrder,
+} from "@t3tools/contracts/settings";
 import type { AsyncResult } from "effect/reactivity";
 import {
   effectiveSnoozed,
@@ -194,6 +198,24 @@ export function resolveSidebarThreadSection(input: {
   return "active";
 }
 
+export type SidebarRowLines = 1 | 2 | 3;
+
+const SIDEBAR_ROW_LINES = { one: 1, two: 2, three: 3 } as const;
+
+// Snoozed and Settled rows stay on one line. Automatic keeps the looks rows had
+// before the setting: cards outside folders, the retired switch inside them.
+export function resolveSidebarRowLines(input: {
+  readonly setting: SidebarThreadRowLines;
+  readonly section: SidebarSection;
+  readonly nested: boolean;
+  readonly folderRowsMultiline: boolean;
+}): SidebarRowLines {
+  if (input.section === "snoozed" || input.section === "settled") return 1;
+  if (input.setting !== "automatic") return SIDEBAR_ROW_LINES[input.setting];
+  if (!input.nested) return 3;
+  return input.folderRowsMultiline ? 2 : 1;
+}
+
 const SIDEBAR_MARKER_PREFIX = "sidebar-marker-";
 
 export type SidebarListMarker =
diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index 8fa58d8456f75..0d9f3fa3a3676 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -191,6 +191,7 @@ import {
   resolveSidebarSweepKeys,
   resolveSidebarDropTarget,
   resolveSidebarDropVerb,
+  resolveSidebarRowLines,
   resolveSidebarThreadSection,
   resolveSidebarReorderableThreadKeys,
   searchSidebarThreads,
@@ -992,6 +993,7 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
   });
   const boringSidebarEnabled = useClientSettings((settings) => settings.boringSidebarEnabled);
   const folderRowsMultiline = useClientSettings((settings) => settings.boringSidebarMultilineRows);
+  const rowLinesSetting = useClientSettings((settings) => settings.sidebarThreadRowLines);
   const newThreadContext = useHandleNewThread();
   // Row callbacks capture only the handler; the rest of the context changes with the route.
   const { handleNewThread } = newThreadContext;
@@ -3323,15 +3325,13 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
                         const threadKey = scopedThreadKey(
                           scopeThreadRef(thread.environmentId, thread.id),
                         );
-                        const isCard =
-                          section === "active" || section === "pinned" || section === "working";
-                        const rowVariant = folderRow
-                          ? folderRowsMultiline
-                            ? "folder-multiline"
-                            : "folder"
-                          : isCard
-                            ? "card"
-                            : "slim";
+                        const nested = folderRow !== undefined;
+                        const rowLines = resolveSidebarRowLines({
+                          setting: rowLinesSetting,
+                          section,
+                          nested,
+                          folderRowsMultiline,
+                        });
                         return (
                           <SortableThreadRow
                             key={threadKey}
@@ -3343,7 +3343,8 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
                               optimisticDrop !== null
                             }
                             thread={thread}
-                            variant={rowVariant}
+                            lines={rowLines}
+                            nested={nested}
                             navigationParent={
                               folderRow ??
                               (section === "working" ||
diff --git a/apps/web/src/components/settings/LabsSettingsPanel.tsx b/apps/web/src/components/settings/LabsSettingsPanel.tsx
index 38be7d611518e..a7f49c12ff2ee 100644
--- a/apps/web/src/components/settings/LabsSettingsPanel.tsx
+++ b/apps/web/src/components/settings/LabsSettingsPanel.tsx
@@ -1,10 +1,13 @@
 import { useAuth } from "@clerk/react";
 import { Link } from "@tanstack/react-router";
 import { managedCapabilityDenial } from "@t3tools/contracts";
+import { SidebarThreadRowLines } from "@t3tools/contracts/settings";
+import * as Schema from "effect/Schema";
 
 import { hasCloudPublicConfig } from "~/cloud/publicConfig";
 import { useT3ConnectAuthPrompt } from "../clerk/useT3ConnectAuthPrompt";
 import { Button } from "../ui/button";
+import { Select, SelectItem, SelectPopup, SelectTrigger, SelectValue } from "../ui/select";
 import { Switch } from "../ui/switch";
 import { ScopedSwitch } from "./ScopedSwitch";
 import { SettingsPageContainer, SettingsRow, SettingsSection } from "./settingsLayout";
@@ -19,6 +22,7 @@ export function LabsSettingsPanel() {
     <SettingsPageContainer>
       <SettingsSection id="beta" title="Beta">
         <BoringSidebarRow />
+        <ThreadRowLinesRow />
         {/* Clerk is only mounted when this build has T3 Connect. */}
         {hasCloudPublicConfig() ? <GuestLinksRowWithSignIn /> : <GuestLinksRow />}
         <LinkedEnvironmentsRow />
@@ -44,32 +48,47 @@ function BoringSidebarRow() {
           aria-label="Boring sidebar (group by project)"
         />
       }
-    >
-      {settings.boringSidebarEnabled ? (
-        <div className="mt-2 mb-2 border-l-2 border-border/60 ps-3">
-          <BoringSidebarMultilineRow />
-        </div>
-      ) : null}
-    </SettingsRow>
+    />
   );
 }
 
-function BoringSidebarMultilineRow() {
+const THREAD_ROW_LINES_LABELS: Record<SidebarThreadRowLines, string> = {
+  automatic: "Automatic",
+  one: "1 line",
+  two: "2 lines",
+  three: "3 lines",
+};
+
+const isSidebarThreadRowLines = Schema.is(SidebarThreadRowLines);
+
+function ThreadRowLinesRow() {
   const settings = useScopedSettings();
   const updateSettings = useUpdateScopedSettings();
   return (
     <SettingsRow
-      {...searchableSetting("boring-sidebar-multiline")}
-      className="px-0 py-2 sm:px-0"
-      description="Show folder threads on two lines: the title, then the branch, pull request, and agent."
+      {...searchableSetting("sidebar-thread-row-lines")}
+      description="Lines per sidebar thread: the title, then its branch, pull request, and agent, then its project. Automatic uses three, and one inside project folders. Snoozed and Settled always use one."
       control={
-        <Switch
-          checked={settings.boringSidebarMultilineRows}
-          onCheckedChange={(checked) =>
-            updateSettings({ boringSidebarMultilineRows: Boolean(checked) })
-          }
-          aria-label="Two-line folder rows"
-        />
+        <div className="w-full sm:w-40">
+          <Select
+            value={settings.sidebarThreadRowLines}
+            onValueChange={(value) => {
+              if (!isSidebarThreadRowLines(value)) return;
+              // Any pick retires the old two-line switch, so Automatic can return to one line.
+              updateSettings({ sidebarThreadRowLines: value, boringSidebarMultilineRows: false });
+            }}
+          >
+            <SelectTrigger size="sm" className="w-full min-w-0" aria-label="Thread rows">
+              <SelectValue>{THREAD_ROW_LINES_LABELS[settings.sidebarThreadRowLines]}</SelectValue>
+            </SelectTrigger>
+            <SelectPopup align="end" alignItemWithTrigger={false}>
+              <SelectItem value="automatic">Automatic</SelectItem>
+              <SelectItem value="one">1 line</SelectItem>
+              <SelectItem value="two">2 lines</SelectItem>
+              <SelectItem value="three">3 lines</SelectItem>
+            </SelectPopup>
+          </Select>
+        </div>
       }
     />
   );
diff --git a/apps/web/src/components/settings/settingsSearch.ts b/apps/web/src/components/settings/settingsSearch.ts
index 4f61ba41c0d86..eb25e16738ba6 100644
--- a/apps/web/src/components/settings/settingsSearch.ts
+++ b/apps/web/src/components/settings/settingsSearch.ts
@@ -468,12 +468,12 @@ export const SETTINGS_SEARCH_ITEMS = [
     searchTerms: ["beta folders project tree classic sidebar"],
   },
   {
-    id: "boring-sidebar-multiline",
-    title: "Two-line folder rows",
+    id: "sidebar-thread-row-lines",
+    title: "Thread rows",
     to: "/settings/labs",
-    // Shown inside the boring sidebar row only while it is on, so search lands on the parent.
-    targetId: "boring-sidebar",
-    searchTerms: ["beta boring sidebar folder rows multiline branch pull request details"],
+    searchTerms: [
+      "beta sidebar thread rows lines compact dense card one two three multiline branch pull request",
+    ],
   },
   {
     id: "tool-call-visibility",
diff --git a/apps/web/src/components/sidebar/SidebarThreadRow.tsx b/apps/web/src/components/sidebar/SidebarThreadRow.tsx
index 05e8984200470..d16e81d6465f6 100644
--- a/apps/web/src/components/sidebar/SidebarThreadRow.tsx
+++ b/apps/web/src/components/sidebar/SidebarThreadRow.tsx
@@ -85,6 +85,7 @@ import {
   hasUnseenCompletion,
   resolveSidebarRowAccessibility,
   type SidebarDropVerb,
+  type SidebarRowLines,
   resolveSidebarThreadStatus,
   resolveThreadLastVisitedAt,
   shouldRecedeSidebarThread,
@@ -488,8 +489,15 @@ export function SortableThreadRow(
       : rowProps.thread.runtime !== null
         ? asLaunchingThread(liveThread)
         : liveThread;
-  // Keyed by variant so a card/slim switch remounts the row.
-  return <SidebarThreadRow key={rowProps.variant} {...rowProps} thread={thread} sortable={bag} />;
+  // Keyed by shape so a card/slim switch remounts the row.
+  return (
+    <SidebarThreadRow
+      key={`${rowProps.lines}:${rowProps.nested}`}
+      {...rowProps}
+      thread={thread}
+      sortable={bag}
+    />
+  );
 }
 export type SidebarSweepAction = "settle" | "unsettle" | "unsnooze";
 const dropVerbBadge: Record<SidebarDropVerb, ReactNode> = {
@@ -543,9 +551,10 @@ function TopStatusIcon(props: { icon: keyof typeof TOP_STATUS_ICONS; className:
 
 type SidebarThreadRowProps = {
   thread: SidebarThreadSummary;
-  // "folder" is a one-line row inside a boring sidebar project folder;
-  // "folder-multiline" adds the card's branch and PR line under it.
-  variant: "card" | "slim" | "folder" | "folder-multiline";
+  // 1 is the title, 2 adds the branch and PR line, 3 is the card with the project on top.
+  lines: SidebarRowLines;
+  // Inside a boring sidebar project folder, which already shows the project.
+  nested: boolean;
   navigationParent?: string | undefined;
   variantAction: SidebarSweepAction;
   settlementSupported: boolean;
@@ -659,9 +668,12 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
     openPullRequestsInRightPanel,
     renamingTitle,
     thread,
-    variant,
+    lines,
+    nested,
     variantAction,
   } = props;
+  // Snoozed and Settled rows recede and show a time; live rows show their status.
+  const live = variantAction === "settle";
   const threadRef = scopeThreadRef(thread.environmentId, thread.id);
   const threadKey = scopedThreadKey(threadRef);
   const canOperateThread = useEnvironmentScope(thread.environmentId, AuthOrchestrationOperateScope);
@@ -1036,7 +1048,7 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
       className={cn(
         "min-w-0 flex-1 text-start text-sm transition-opacity motion-reduce:transition-none",
         shouldRecede ? "font-normal" : "font-medium",
-        variant !== "slim"
+        live
           ? cn(
               "truncate",
               shouldRecede
@@ -1208,9 +1220,8 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
     </span>
   ) : null;
 
-  if (variant !== "card") {
-    const multiline = variant === "folder-multiline";
-    const inFolder = variant === "folder" || multiline;
+  if (lines !== 3) {
+    const multiline = lines === 2;
     return (
       <li
         data-thread-item={threadKey}
@@ -1233,7 +1244,7 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
                 data-sidebar-parent={props.navigationParent}
                 aria-label={accessibility.label}
                 aria-current={accessibility.current}
-                data-testid={inFolder ? "sidebar-row-folder" : "sidebar-row-slim"}
+                data-testid={nested ? "sidebar-row-folder" : "sidebar-row-slim"}
                 aria-busy={isRegeneratingTitle || undefined}
                 className={cn(
                   rowSurfaceClassName,
@@ -1241,7 +1252,7 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
                     ? "flex flex-col justify-center px-2.5 py-1.5"
                     : "flex h-9 items-center gap-2.5 px-2.5",
                   // Lines titles up with the folder name, past its chevron and icon.
-                  inFolder && "ps-9",
+                  nested && "ps-9",
                 )}
                 onClick={handleClick}
                 onDoubleClick={handleDoubleClick}
@@ -1253,11 +1264,12 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
             {/* `contents` keeps one-line rows a single flex row. */}
             <div className={multiline ? "flex h-6 min-w-0 items-center gap-2.5" : "contents"}>
               {accessibleTitle}
-              {inFolder ? null : (
+              {nested ? null : (
                 <span
                   className={cn(
                     "flex shrink-0 items-center transition-opacity",
-                    (!props.isActive || variantAction === "unsettle") &&
+                    !live &&
+                      (!props.isActive || variantAction === "unsettle") &&
                       "opacity-40 grayscale group-focus-within/sidebar-row:opacity-100 group-focus-within/sidebar-row:grayscale-0 group-hover/sidebar-row:opacity-100 group-hover/sidebar-row:grayscale-0",
                   )}
                 >
@@ -1298,7 +1310,7 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
                         <AlarmClockIcon aria-hidden className="size-3" />
                         {props.snoozeWakeLabelText}
                       </span>
-                    ) : (inFolder ? isWokeStatus : isWoke) ? (
+                    ) : (live ? isWokeStatus : isWoke) ? (
                       <Tooltip>
                         <TooltipTrigger
                           render={
@@ -1315,8 +1327,8 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
                         />
                         <TooltipPopup side="top">Dismiss Woke notification</TooltipPopup>
                       </Tooltip>
-                    ) : inFolder && topStatus ? (
-                      // Folder rows have no status line, so the status takes the time slot.
+                    ) : live && topStatus ? (
+                      // These rows have no status line, so the status takes the time slot.
                       <span
                         className={cn(
                           "inline-flex items-center gap-1 text-xs font-medium",
@@ -1399,7 +1411,10 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
               )}
               {props.sweepAction !== null ? dragDestination : null}
             </div>
-            {multiline ? metaLine : null}
+            {multiline && metaLine !== null ? (
+              // Lines the details up with the title, past the project icon.
+              <div className={cn(!nested && "ps-6.5")}>{metaLine}</div>
+            ) : null}
           </TooltipTrigger>
           {detailsTooltip}
         </Tooltip>
@@ -1444,17 +1459,18 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: SidebarThreadRowP
             className={cn(
               "relative z-10 h-[4.875rem] px-(--sidebar-row-content-inset) py-(--sidebar-content-inset)",
               metaLineEmpty && "h-auto",
+              nested && "ps-9",
             )}
           >
             <div className="flex h-5 min-w-0 items-center gap-1.5">
               {draftIndicator}
-              {props.project ? (
+              {props.project && !nested ? (
                 <ProjectFavicon project={props.project} className="size-4 shrink-0" />
               ) : null}
               {/* Left of the status slot, the pin would slide when hover swaps the
                 label for the wider row controls. */}
               {pinIndicator}
-              {props.projectDisplayName ? (
+              {props.projectDisplayName && !nested ? (
                 <span
                   className={cn("min-w-0 flex-1 truncate font-normal text-secondary-label text-xs")}
                 >
diff --git a/docs/user/thread-sidebar.md b/docs/user/thread-sidebar.md
index 09ce63e2a3e65..bbe1efff39829 100644
--- a/docs/user/thread-sidebar.md
+++ b/docs/user/thread-sidebar.md
@@ -159,6 +159,14 @@ Pinned threads stay above the folders, and Snoozed and Settled stay below them.
 can drag a thread onto the composer to mention it, but not within the sidebar, and the Working
 section is off. Each device keeps its own choice.
 
+### Thread rows (beta)
+
+On web and desktop, **Settings → Labs → Thread rows** sets how many lines each sidebar thread
+takes: **1 line** shows the title and status, **2 lines** adds the branch, pull request, and agent,
+and **3 lines** adds a line for the project and status above the title. Inside a project folder,
+that line shows only the status. **Automatic** uses three lines, and one inside project folders.
+Snoozed and Settled threads always take one line.
+
 ## Settle finished work
 
 Choose **Settle thread** from its menu to move finished work out of the active list
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index 346213992e4b2..4324a6be0e83d 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -350,6 +350,9 @@ export type ToolCallVisibility = typeof ToolCallVisibility.Type;
 export const ScreenReaderAnnouncements = Schema.Literals(["status", "messages", "everything"]);
 export type ScreenReaderAnnouncements = typeof ScreenReaderAnnouncements.Type;
 
+export const SidebarThreadRowLines = Schema.Literals(["automatic", "one", "two", "three"]);
+export type SidebarThreadRowLines = typeof SidebarThreadRowLines.Type;
+
 export const ModelFavorite = Schema.Struct({
   provider: ProviderInstanceId,
   model: TrimmedNonEmptyString,
@@ -515,9 +518,13 @@ export const ClientSettingsSchema = Schema.Struct({
   proactivePanelsEnabled: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(false))),
   showSkillsInSlashMenu: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(true))),
   boringSidebarEnabled: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(false))),
+  // Retired Labs toggle. Automatic's folder rows read it until a Thread rows pick clears it.
   boringSidebarMultilineRows: Schema.Boolean.pipe(
     Schema.withDecodingDefault(Effect.succeed(false)),
   ),
+  sidebarThreadRowLines: SidebarThreadRowLines.pipe(
+    Schema.withDecodingDefault(Effect.succeed("automatic" as const)),
+  ),
   toolCallVisibility: ToolCallVisibility.pipe(
     Schema.withDecodingDefault(Effect.succeed("showAll" as const)),
   ),
@@ -2035,6 +2042,7 @@ export const ClientSettingsPatch = Schema.Struct({
   showSkillsInSlashMenu: Schema.optionalKey(Schema.Boolean),
   boringSidebarEnabled: Schema.optionalKey(Schema.Boolean),
   boringSidebarMultilineRows: Schema.optionalKey(Schema.Boolean),
+  sidebarThreadRowLines: Schema.optionalKey(SidebarThreadRowLines),
   toolCallVisibility: Schema.optionalKey(ToolCallVisibility),
   screenReaderAnnouncements: Schema.optionalKey(ScreenReaderAnnouncements),
   threadDetailsUsageEnabled: Schema.optionalKey(Schema.Boolean),