diff --git a/KEYBINDINGS.md b/KEYBINDINGS.md
index b57c13032c..e8a31ef44a 100644
--- a/KEYBINDINGS.md
+++ b/KEYBINDINGS.md
@@ -24,6 +24,7 @@ See the full schema for more details: [`packages/contracts/src/keybindings.ts`](
   { "key": "mod+n", "command": "terminal.new", "when": "terminalFocus" },
   { "key": "mod+w", "command": "terminal.close", "when": "terminalFocus" },
   { "key": "mod+k", "command": "commandPalette.toggle", "when": "!terminalFocus" },
+  { "key": "mod+b", "command": "sidebar.toggle", "when": "!terminalFocus" },
   { "key": "mod+n", "command": "chat.new", "when": "!terminalFocus" },
   { "key": "mod+shift+o", "command": "chat.new", "when": "!terminalFocus" },
   { "key": "mod+shift+n", "command": "chat.newLocal", "when": "!terminalFocus" },
@@ -52,6 +53,7 @@ Invalid rules are ignored. Invalid config files are ignored. Warnings are logged
 - `terminal.new`: create new terminal (in focused terminal context by default)
 - `terminal.close`: close/kill the focused terminal (in focused terminal context by default)
 - `commandPalette.toggle`: open or close the global command palette
+- `sidebar.toggle`: open or close the thread sidebar
 - `chat.new`: create a new chat thread preserving the active thread's branch/worktree state
 - `chat.newLocal`: create a new chat thread for the active project in a new environment (local/worktree determined by app settings (default `local`))
 - `editor.openFavorite`: open current project/worktree in the last-used editor
diff --git a/apps/web/src/components/AppSidebarLayout.tsx b/apps/web/src/components/AppSidebarLayout.tsx
index d98f30a1e5..bdb062db9a 100644
--- a/apps/web/src/components/AppSidebarLayout.tsx
+++ b/apps/web/src/components/AppSidebarLayout.tsx
@@ -2,7 +2,7 @@ import { useEffect, type ReactNode } from "react";
 import { useNavigate } from "@tanstack/react-router";
 
 import ThreadSidebar from "./Sidebar";
-import { Sidebar, SidebarProvider, SidebarRail } from "./ui/sidebar";
+import { Sidebar, SidebarRail } from "./ui/sidebar";
 import {
   clearShortcutModifierState,
   syncShortcutModifierStateFromKeyboardEvent,
@@ -54,7 +54,7 @@ export function AppSidebarLayout({ children }: { children: ReactNode }) {
   }, [navigate]);
 
   return (
-    <SidebarProvider className="h-dvh! min-h-0!" defaultOpen>
+    <>
       <Sidebar
         side="left"
         collapsible="offcanvas"
@@ -70,6 +70,6 @@ export function AppSidebarLayout({ children }: { children: ReactNode }) {
         <SidebarRail />
       </Sidebar>
       {children}
-    </SidebarProvider>
+    </>
   );
 }
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index 9ef221e262..b4a91bb274 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -3504,6 +3504,8 @@ export default function ChatView(props: ChatViewProps) {
           isElectron
             ? cn(
                 "drag-region flex h-[52px] items-center px-3 sm:px-5 wco:h-[env(titlebar-area-height)]",
+                "transition-[padding-left] duration-200 ease-linear",
+                "group-data-[state=collapsed]/sidebar-wrapper:pl-[90px] group-data-[state=collapsed]/sidebar-wrapper:wco:pl-[calc(env(titlebar-area-x)+1em)]",
                 reserveTitleBarControlInset &&
                   "wco:pr-[calc(100vw-env(titlebar-area-width)-env(titlebar-area-x)+1em)]",
               )
diff --git a/apps/web/src/components/CommandPalette.tsx b/apps/web/src/components/CommandPalette.tsx
index 027688a284..0734bbe138 100644
--- a/apps/web/src/components/CommandPalette.tsx
+++ b/apps/web/src/components/CommandPalette.tsx
@@ -23,6 +23,7 @@ import {
   FolderPlusIcon,
   LinkIcon,
   MessageSquareIcon,
+  PanelLeftIcon,
   SettingsIcon,
   SquarePenIcon,
 } from "lucide-react";
@@ -115,6 +116,7 @@ import {
 import { Button } from "./ui/button";
 import { Kbd, KbdGroup } from "./ui/kbd";
 import { stackedThreadToast, toastManager } from "./ui/toast";
+import { useSidebar } from "./ui/sidebar";
 import { Tooltip, TooltipPopup, TooltipTrigger } from "./ui/tooltip";
 import { ComposerHandleContext, useComposerHandleContext } from "../composerHandleContext";
 import type { ChatComposerHandle } from "./chat/ChatComposer";
@@ -392,6 +394,7 @@ function CommandPaletteDialog() {
 
 function OpenCommandPaletteDialog() {
   const navigate = useNavigate();
+  const { toggleSidebar } = useSidebar();
   const setOpen = useCommandPaletteStore((store) => store.setOpen);
   const openIntent = useCommandPaletteStore((store) => store.openIntent);
   const clearOpenIntent = useCommandPaletteStore((store) => store.clearOpenIntent);
@@ -1050,6 +1053,18 @@ function OpenCommandPaletteDialog() {
     },
   });
 
+  actionItems.push({
+    kind: "action",
+    value: "action:toggle-sidebar",
+    searchTerms: ["sidebar", "toggle", "collapse", "hide", "show"],
+    title: "Toggle sidebar",
+    icon: <PanelLeftIcon className={ITEM_ICON_CLASS} />,
+    shortcutCommand: "sidebar.toggle",
+    run: async () => {
+      toggleSidebar();
+    },
+  });
+
   actionItems.push({
     kind: "action",
     value: "action:settings",
diff --git a/apps/web/src/components/NoActiveThreadState.tsx b/apps/web/src/components/NoActiveThreadState.tsx
index cd1f76ed2c..ecedc1cd20 100644
--- a/apps/web/src/components/NoActiveThreadState.tsx
+++ b/apps/web/src/components/NoActiveThreadState.tsx
@@ -11,7 +11,11 @@ export function NoActiveThreadState() {
           className={cn(
             "border-b border-border px-3 sm:px-5",
             isElectron
-              ? "drag-region flex h-[52px] items-center wco:h-[env(titlebar-area-height)]"
+              ? cn(
+                  "drag-region flex h-[52px] items-center wco:h-[env(titlebar-area-height)]",
+                  "transition-[padding-left] duration-200 ease-linear",
+                  "group-data-[state=collapsed]/sidebar-wrapper:pl-[90px] group-data-[state=collapsed]/sidebar-wrapper:wco:pl-[calc(env(titlebar-area-x)+1em)]",
+                )
               : "py-2 sm:py-3",
           )}
         >
diff --git a/apps/web/src/components/ui/sidebar.tsx b/apps/web/src/components/ui/sidebar.tsx
index 32206be708..e6efa71f2b 100644
--- a/apps/web/src/components/ui/sidebar.tsx
+++ b/apps/web/src/components/ui/sidebar.tsx
@@ -155,6 +155,7 @@ function SidebarProvider({
           className,
         )}
         data-slot="sidebar-wrapper"
+        data-state={state}
         style={
           {
             "--sidebar-width": SIDEBAR_WIDTH,
diff --git a/apps/web/src/keybindings.test.ts b/apps/web/src/keybindings.test.ts
index 85c14fa0ab..1b8c50d389 100644
--- a/apps/web/src/keybindings.test.ts
+++ b/apps/web/src/keybindings.test.ts
@@ -110,6 +110,11 @@ const DEFAULT_BINDINGS = compile([
     command: "commandPalette.toggle",
     whenAst: whenNot(whenIdentifier("terminalFocus")),
   },
+  {
+    shortcut: modShortcut("b"),
+    command: "sidebar.toggle",
+    whenAst: whenNot(whenIdentifier("terminalFocus")),
+  },
   {
     shortcut: modShortcut("m", { shiftKey: true }),
     command: "modelPicker.toggle",
@@ -291,6 +296,14 @@ describe("shortcutLabelForCommand", () => {
       shortcutLabelForCommand(DEFAULT_BINDINGS, "commandPalette.toggle", "MacIntel"),
       "⌘K",
     );
+    assert.strictEqual(
+      shortcutLabelForCommand(DEFAULT_BINDINGS, "sidebar.toggle", "MacIntel"),
+      "⌘B",
+    );
+    assert.strictEqual(
+      shortcutLabelForCommand(DEFAULT_BINDINGS, "sidebar.toggle", "Linux"),
+      "Ctrl+B",
+    );
     assert.strictEqual(
       shortcutLabelForCommand(DEFAULT_BINDINGS, "modelPicker.toggle", "Linux"),
       "Ctrl+Shift+M",
@@ -478,6 +491,30 @@ describe("chat/editor shortcuts", () => {
     );
   });
 
+  it("matches sidebar.toggle shortcut outside terminal focus", () => {
+    assert.strictEqual(
+      resolveShortcutCommand(event({ key: "b", metaKey: true }), DEFAULT_BINDINGS, {
+        platform: "MacIntel",
+        context: { terminalFocus: false },
+      }),
+      "sidebar.toggle",
+    );
+    assert.strictEqual(
+      resolveShortcutCommand(event({ key: "b", ctrlKey: true }), DEFAULT_BINDINGS, {
+        platform: "Linux",
+        context: { terminalFocus: false },
+      }),
+      "sidebar.toggle",
+    );
+    assert.notStrictEqual(
+      resolveShortcutCommand(event({ key: "b", metaKey: true }), DEFAULT_BINDINGS, {
+        platform: "MacIntel",
+        context: { terminalFocus: true },
+      }),
+      "sidebar.toggle",
+    );
+  });
+
   it("matches diff.toggle shortcut outside terminal focus", () => {
     assert.isTrue(
       isDiffToggleShortcut(event({ key: "d", metaKey: true }), DEFAULT_BINDINGS, {
diff --git a/apps/web/src/routes/__root.tsx b/apps/web/src/routes/__root.tsx
index 58617589df..443c7d75ff 100644
--- a/apps/web/src/routes/__root.tsx
+++ b/apps/web/src/routes/__root.tsx
@@ -14,6 +14,7 @@ import { APP_DISPLAY_NAME } from "../branding";
 import { AppSidebarLayout } from "../components/AppSidebarLayout";
 import { CommandPalette } from "../components/CommandPalette";
 import { SshPasswordPromptDialog } from "../components/desktop/SshPasswordPromptDialog";
+import { SidebarProvider } from "../components/ui/sidebar";
 import {
   SlowRpcAckToastCoordinator,
   WebSocketConnectionCoordinator,
@@ -120,11 +121,13 @@ function RootRouteView() {
   }
 
   const appShell = (
-    <CommandPalette>
-      <AppSidebarLayout>
-        <Outlet />
-      </AppSidebarLayout>
-    </CommandPalette>
+    <SidebarProvider className="h-dvh! min-h-0!" defaultOpen>
+      <CommandPalette>
+        <AppSidebarLayout>
+          <Outlet />
+        </AppSidebarLayout>
+      </CommandPalette>
+    </SidebarProvider>
   );
 
   return (
diff --git a/apps/web/src/routes/_chat.tsx b/apps/web/src/routes/_chat.tsx
index da22d7e602..7eb54c7b2d 100644
--- a/apps/web/src/routes/_chat.tsx
+++ b/apps/web/src/routes/_chat.tsx
@@ -12,6 +12,7 @@ import { resolveShortcutCommand } from "../keybindings";
 import { selectThreadTerminalState, useTerminalStateStore } from "../terminalStateStore";
 import { useThreadSelectionStore } from "../threadSelectionStore";
 import { resolveSidebarNewThreadEnvMode } from "~/components/Sidebar.logic";
+import { useSidebar } from "~/components/ui/sidebar";
 import { useSettings } from "~/hooks/useSettings";
 import { useServerKeybindings } from "~/rpc/serverState";
 
@@ -27,6 +28,7 @@ function ChatRouteGlobalShortcuts() {
       : false,
   );
   const appSettings = useSettings();
+  const { toggleSidebar } = useSidebar();
 
   useEffect(() => {
     const onWindowKeyDown = (event: KeyboardEvent) => {
@@ -94,6 +96,32 @@ function ChatRouteGlobalShortcuts() {
     appSettings.defaultThreadEnvMode,
   ]);
 
+  // Sidebar toggle runs on capture phase so it wins over in-editor handlers
+  // (Lexical claims mod+b for bold and calls preventDefault, which would
+  // otherwise trip the `event.defaultPrevented` guard above).
+  useEffect(() => {
+    const onWindowKeyDownCapture = (event: KeyboardEvent) => {
+      if (useCommandPaletteStore.getState().open) {
+        return;
+      }
+      const command = resolveShortcutCommand(event, keybindings, {
+        context: {
+          terminalFocus: isTerminalFocused(),
+          terminalOpen,
+        },
+      });
+      if (command !== "sidebar.toggle") return;
+      event.preventDefault();
+      event.stopPropagation();
+      toggleSidebar();
+    };
+
+    window.addEventListener("keydown", onWindowKeyDownCapture, true);
+    return () => {
+      window.removeEventListener("keydown", onWindowKeyDownCapture, true);
+    };
+  }, [keybindings, terminalOpen, toggleSidebar]);
+
   return null;
 }
 
diff --git a/apps/web/src/routes/settings.tsx b/apps/web/src/routes/settings.tsx
index ec98e7ee36..8cbf7ca6a4 100644
--- a/apps/web/src/routes/settings.tsx
+++ b/apps/web/src/routes/settings.tsx
@@ -78,7 +78,7 @@ function SettingsContentLayout() {
         )}
 
         {isElectron && (
-          <div className="drag-region flex h-[52px] shrink-0 items-center border-b border-border px-5 wco:h-[env(titlebar-area-height)] wco:pr-[calc(100vw-env(titlebar-area-width)-env(titlebar-area-x)+1em)]">
+          <div className="drag-region flex h-[52px] shrink-0 items-center border-b border-border px-5 transition-[padding-left] duration-200 ease-linear wco:h-[env(titlebar-area-height)] wco:pr-[calc(100vw-env(titlebar-area-width)-env(titlebar-area-x)+1em)] group-data-[state=collapsed]/sidebar-wrapper:pl-[90px] group-data-[state=collapsed]/sidebar-wrapper:wco:pl-[calc(env(titlebar-area-x)+1em)]">
             <span className="text-xs font-medium tracking-wide text-muted-foreground/70">
               Settings
             </span>
diff --git a/packages/contracts/src/keybindings.ts b/packages/contracts/src/keybindings.ts
index d3b85d1cda..63afd51f9f 100644
--- a/packages/contracts/src/keybindings.ts
+++ b/packages/contracts/src/keybindings.ts
@@ -54,6 +54,7 @@ const STATIC_KEYBINDING_COMMANDS = [
   "terminal.close",
   "diff.toggle",
   "commandPalette.toggle",
+  "sidebar.toggle",
   "chat.new",
   "chat.newLocal",
   "editor.openFavorite",
diff --git a/packages/shared/src/keybindings.ts b/packages/shared/src/keybindings.ts
index c67ad784fe..aec05496bb 100644
--- a/packages/shared/src/keybindings.ts
+++ b/packages/shared/src/keybindings.ts
@@ -25,6 +25,7 @@ export const DEFAULT_KEYBINDINGS: ReadonlyArray<KeybindingRule> = [
   { key: "mod+w", command: "terminal.close", when: "terminalFocus" },
   { key: "mod+d", command: "diff.toggle", when: "!terminalFocus" },
   { key: "mod+k", command: "commandPalette.toggle", when: "!terminalFocus" },
+  { key: "mod+b", command: "sidebar.toggle", when: "!terminalFocus" },
   { key: "mod+n", command: "chat.new", when: "!terminalFocus" },
   { key: "mod+shift+o", command: "chat.new", when: "!terminalFocus" },
   { key: "mod+shift+n", command: "chat.newLocal", when: "!terminalFocus" },