diff --git a/apps/web/app/components/workspace/chat-sessions-sidebar.tsx b/apps/web/app/components/workspace/chat-sessions-sidebar.tsx
index 694785e5a9c..0aa8d09f94d 100644
--- a/apps/web/app/components/workspace/chat-sessions-sidebar.tsx
+++ b/apps/web/app/components/workspace/chat-sessions-sidebar.tsx
@@ -38,6 +38,8 @@ type ChatSessionsSidebarProps = {
 	mobile?: boolean;
 	/** Close the mobile drawer. */
 	onClose?: () => void;
+	/** Fixed width in px when not mobile (overrides default 260). */
+	width?: number;
 };
 
 /** Format a timestamp into a human-readable relative time string. */
@@ -123,6 +125,7 @@ export function ChatSessionsSidebar({
 	onSelectSubagent,
 	mobile,
 	onClose,
+	width: widthProp,
 }: ChatSessionsSidebarProps) {
 	const [hoveredId, setHoveredId] = useState<string | null>(null);
 
@@ -160,11 +163,12 @@ export function ChatSessionsSidebar({
 	// Group sessions: today, yesterday, this week, this month, older
 	const grouped = groupSessions(sessions);
 
+	const width = mobile ? "280px" : (widthProp ?? 260);
 	const sidebar = (
 		<aside
 			className={`flex flex-col h-full flex-shrink-0 ${mobile ? "drawer-right" : "border-l"}`}
 			style={{
-				width: mobile ? "280px" : 260,
+				width: typeof width === "number" ? `${width}px` : width,
 				borderColor: "var(--color-border)",
 				background: "var(--color-surface)",
 			}}
diff --git a/apps/web/app/components/workspace/profile-switcher.tsx b/apps/web/app/components/workspace/profile-switcher.tsx
index 035ceab949b..7223180c06c 100644
--- a/apps/web/app/components/workspace/profile-switcher.tsx
+++ b/apps/web/app/components/workspace/profile-switcher.tsx
@@ -10,12 +10,21 @@ export type ProfileInfo = {
   hasConfig: boolean;
 };
 
+export type ProfileSwitcherTriggerProps = {
+  isOpen: boolean;
+  onClick: () => void;
+  activeProfile: string;
+  switching: boolean;
+};
+
 type ProfileSwitcherProps = {
   onProfileSwitch?: () => void;
   onCreateWorkspace?: () => void;
+  /** When set, this renders instead of the default button; dropdown still opens below. */
+  trigger?: (props: ProfileSwitcherTriggerProps) => React.ReactNode;
 };
 
-export function ProfileSwitcher({ onProfileSwitch, onCreateWorkspace }: ProfileSwitcherProps) {
+export function ProfileSwitcher({ onProfileSwitch, onCreateWorkspace, trigger }: ProfileSwitcherProps) {
   const [profiles, setProfiles] = useState<ProfileInfo[]>([]);
   const [activeProfile, setActiveProfile] = useState("default");
   const [isOpen, setIsOpen] = useState(false);
@@ -78,35 +87,51 @@ export function ProfileSwitcher({ onProfileSwitch, onCreateWorkspace }: ProfileS
 
   // Don't show the switcher if there's only one profile and no way to create more
   const showSwitcher = profiles.length > 0;
-  if (!showSwitcher) {return null;}
+  const handleToggle = () => {
+    if (showSwitcher) { setIsOpen((o) => !o); }
+  };
+
+  if (!trigger && !showSwitcher) { return null; }
 
   return (
-    <div className="relative" ref={dropdownRef}>
-      <button
-        onClick={() => setIsOpen(!isOpen)}
-        disabled={switching}
-        className="flex items-center gap-1.5 px-2 py-1 rounded-md text-xs transition-colors hover:bg-[var(--color-surface-hover)] disabled:opacity-50"
-        style={{ color: "var(--color-text-secondary)" }}
-        title="Switch workspace profile"
-      >
-        {/* Workspace icon */}
-        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
-          <path d="M20 20a2 2 0 0 0 2-2V8a2 2 0 0 0-2-2h-7.9a2 2 0 0 1-1.69-.9L9.6 3.9A2 2 0 0 0 7.93 3H4a2 2 0 0 0-2 2v13a2 2 0 0 0 2 2Z" />
-        </svg>
-        <span className="truncate max-w-[120px]">
-          {activeProfile === "default" ? "Default" : activeProfile}
-        </span>
-        <svg
-          className={`w-3 h-3 transition-transform ${isOpen ? "rotate-180" : ""}`}
-          fill="none"
-          stroke="currentColor"
-          viewBox="0 0 24 24"
+    <div
+      className={`relative ${trigger ? "flex-1 min-w-0" : ""}`}
+      ref={dropdownRef}
+    >
+      {trigger ? (
+        trigger({
+          isOpen,
+          onClick: handleToggle,
+          activeProfile,
+          switching,
+        })
+      ) : (
+        <button
+          onClick={handleToggle}
+          disabled={switching}
+          className="flex items-center gap-1.5 px-2 py-1 rounded-md text-xs transition-colors hover:bg-[var(--color-surface-hover)] disabled:opacity-50"
+          style={{ color: "var(--color-text-secondary)" }}
+          title="Switch workspace profile"
         >
-          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 9l-7 7-7-7" />
-        </svg>
-      </button>
+          {/* Workspace icon */}
+          <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+            <path d="M20 20a2 2 0 0 0 2-2V8a2 2 0 0 0-2-2h-7.9a2 2 0 0 1-1.69-.9L9.6 3.9A2 2 0 0 0 7.93 3H4a2 2 0 0 0-2 2v13a2 2 0 0 0 2 2Z" />
+          </svg>
+          <span className="truncate max-w-[120px]">
+            {activeProfile === "default" ? "Default" : activeProfile}
+          </span>
+          <svg
+            className={`w-3 h-3 transition-transform ${isOpen ? "rotate-180" : ""}`}
+            fill="none"
+            stroke="currentColor"
+            viewBox="0 0 24 24"
+          >
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 9l-7 7-7-7" />
+          </svg>
+        </button>
+      )}
 
-      {isOpen && (
+      {showSwitcher && isOpen && (
         <div
           className="absolute left-0 top-full mt-1 w-64 rounded-lg overflow-hidden z-50"
           style={{
diff --git a/apps/web/app/components/workspace/workspace-sidebar.tsx b/apps/web/app/components/workspace/workspace-sidebar.tsx
index c045cf0297e..0e009608bf3 100644
--- a/apps/web/app/components/workspace/workspace-sidebar.tsx
+++ b/apps/web/app/components/workspace/workspace-sidebar.tsx
@@ -41,6 +41,8 @@ type WorkspaceSidebarProps = {
 	onClose?: () => void;
 	/** Active workspace profile name (null = default). */
 	activeProfile?: string | null;
+	/** Fixed width in px when not mobile (overrides default 260). */
+	width?: number;
 	/** Called after the user switches to a different profile. */
 	onProfileSwitch?: () => void;
 };
@@ -401,15 +403,17 @@ export function WorkspaceSidebar({
 	onClose,
 	activeProfile,
 	onProfileSwitch,
+	width: widthProp,
 }: WorkspaceSidebarProps) {
 	const isBrowsing = browseDir != null;
 	const [showCreateWorkspace, setShowCreateWorkspace] = useState(false);
+	const width = mobile ? "280px" : (widthProp ?? 260);
 
 	const sidebar = (
 		<aside
 			className={`flex flex-col h-screen flex-shrink-0 ${mobile ? "drawer-left" : "border-r"}`}
 			style={{
-				width: mobile ? "280px" : "260px",
+				width: typeof width === "number" ? `${width}px` : width,
 				background: "var(--color-surface)",
 				borderColor: "var(--color-border)",
 			}}
@@ -466,7 +470,7 @@ export function WorkspaceSidebar({
 						<button
 							type="button"
 							onClick={() => void onGoToChat?.()}
-							className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0 cursor-pointer transition-opacity"
+							className="w-8 h-8 rounded-lg flex items-center justify-center shrink-0 cursor-pointer transition-opacity"
 							style={{
 								background: "var(--color-accent-light)",
 								color: "var(--color-accent)",
@@ -480,50 +484,59 @@ export function WorkspaceSidebar({
 								<polyline points="9 22 9 12 15 12 15 22" />
 							</svg>
 						</button>
-						<div className="flex-1 min-w-0">
-							<div
-								className="text-sm font-medium truncate"
-								style={{ color: "var(--color-text)" }}
-							>
-								{orgName || "Workspace"}
-							</div>
-							<div
-								className="text-[11px] flex items-center gap-1"
-								style={{
-									color: "var(--color-text-muted)",
-								}}
-							>
-								<span>Ironclaw</span>
-								{activeProfile && activeProfile !== "default" && (
-									<span
-										className="px-1 py-0.5 rounded text-[10px]"
-										style={{
-											background: "var(--color-accent-light)",
-											color: "var(--color-accent)",
-										}}
+						<ProfileSwitcher
+							onProfileSwitch={onProfileSwitch}
+							onCreateWorkspace={() => setShowCreateWorkspace(true)}
+							trigger={({ isOpen, onClick, activeProfile: profileName, switching }) => (
+								<button
+									type="button"
+									onClick={onClick}
+									disabled={switching}
+									className="flex-1 min-w-0 w-full flex items-center justify-between gap-2 text-left rounded-lg py-1.5 px-2 transition-colors hover:bg-(--color-surface-hover) disabled:opacity-50"
+									style={{ color: "var(--color-text)" }}
+									title="Switch workspace profile"
+								>
+									<div className="min-w-0 truncate">
+										<div
+											className="text-sm font-medium truncate"
+											style={{ color: "var(--color-text)" }}
+										>
+											{orgName || "Workspace"}
+										</div>
+										<div
+											className="text-[11px] flex items-center gap-1 truncate"
+											style={{ color: "var(--color-text-muted)" }}
+										>
+											<span>Ironclaw</span>
+											{profileName && profileName !== "default" && (
+												<span
+													className="px-1 py-0.5 rounded text-[10px] shrink-0"
+													style={{
+														background: "var(--color-accent-light)",
+														color: "var(--color-accent)",
+													}}
+												>
+													{profileName}
+												</span>
+											)}
+										</div>
+									</div>
+									<svg
+										className={`w-3.5 h-3.5 shrink-0 transition-transform ${isOpen ? "rotate-180" : ""}`}
+										fill="none"
+										stroke="currentColor"
+										viewBox="0 0 24 24"
+										style={{ color: "var(--color-text-muted)" }}
 									>
-										{activeProfile}
-									</span>
-								)}
-							</div>
-						</div>
+										<path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 9l-7 7-7-7" />
+									</svg>
+								</button>
+							)}
+						/>
 					</>
 				)}
 			</div>
 
-			{/* Profile switcher — only in workspace mode */}
-			{!isBrowsing && (
-				<div
-					className="px-3 py-1.5 border-b"
-					style={{ borderColor: "var(--color-border)" }}
-				>
-					<ProfileSwitcher
-						onProfileSwitch={onProfileSwitch}
-						onCreateWorkspace={() => setShowCreateWorkspace(true)}
-					/>
-				</div>
-			)}
-
 			{/* Create workspace dialog */}
 			<CreateWorkspaceDialog
 				isOpen={showCreateWorkspace}
diff --git a/apps/web/app/workspace/page.tsx b/apps/web/app/workspace/page.tsx
index f627eba188e..bc206d4c9d1 100644
--- a/apps/web/app/workspace/page.tsx
+++ b/apps/web/app/workspace/page.tsx
@@ -142,6 +142,72 @@ function rawFileUrl(path: string): string {
   return `/api/workspace/raw-file?path=${encodeURIComponent(path)}`;
 }
 
+const LEFT_SIDEBAR_MIN = 200;
+const LEFT_SIDEBAR_MAX = 480;
+const RIGHT_SIDEBAR_MIN = 260;
+const RIGHT_SIDEBAR_MAX = 600;
+const STORAGE_LEFT = "ironclaw-workspace-left-sidebar-width";
+const STORAGE_RIGHT = "ironclaw-workspace-right-sidebar-width";
+
+function clamp(n: number, min: number, max: number): number {
+  return Math.min(max, Math.max(min, n));
+}
+
+/** Vertical resize handle; uses cursor position so the handle follows the mouse (no stuck-at-limit). */
+function ResizeHandle({
+  mode,
+  containerRef,
+  min,
+  max,
+  onResize,
+}: {
+  mode: "left" | "right";
+  containerRef: React.RefObject<HTMLElement | null>;
+  min: number;
+  max: number;
+  onResize: (width: number) => void;
+}) {
+  const [isDragging, setIsDragging] = useState(false);
+  const onMouseDown = useCallback(
+    (e: React.MouseEvent) => {
+      e.preventDefault();
+      setIsDragging(true);
+      const move = (ev: MouseEvent) => {
+        const el = containerRef.current;
+        if (!el) {return;}
+        const rect = el.getBoundingClientRect();
+        const width =
+          mode === "left"
+            ? ev.clientX - rect.left
+            : rect.right - ev.clientX;
+        onResize(clamp(width, min, max));
+      };
+      const up = () => {
+        setIsDragging(false);
+        document.removeEventListener("mousemove", move);
+        document.removeEventListener("mouseup", up);
+        document.body.style.removeProperty("user-select");
+        document.body.style.removeProperty("cursor");
+      };
+      document.body.style.setProperty("user-select", "none");
+      document.body.style.setProperty("cursor", "col-resize");
+      document.addEventListener("mousemove", move);
+      document.addEventListener("mouseup", up);
+    },
+    [containerRef, mode, min, max, onResize],
+  );
+  const showHover = isDragging || undefined;
+  return (
+    <div
+      role="separator"
+      aria-orientation="vertical"
+      onMouseDown={onMouseDown}
+      className={`shrink-0 w-1 cursor-col-resize flex justify-center transition-colors ${showHover ? "bg-blue-600/30" : "hover:bg-blue-600/30"}`}
+      style={{ minWidth: 4 }}
+    />
+  );
+}
+
 /** Find a node in the tree by exact path. */
 function findNode(
   tree: TreeNode[],
@@ -229,6 +295,8 @@ function WorkspacePageInner() {
   const chatRef = useRef<ChatPanelHandle>(null);
   // Compact (file-scoped) chat panel ref for sidebar drag-and-drop
   const compactChatRef = useRef<ChatPanelHandle>(null);
+  // Root layout ref for resize handle position (handle follows cursor)
+  const layoutRef = useRef<HTMLDivElement>(null);
 
   // Live-reactive tree via SSE watcher (with browse-mode support)
   const {
@@ -308,6 +376,26 @@ function WorkspacePageInner() {
   const [sidebarOpen, setSidebarOpen] = useState(false);
   const [chatSessionsOpen, setChatSessionsOpen] = useState(false);
 
+  // Resizable sidebar widths (desktop only; persisted in localStorage)
+  const [leftSidebarWidth, setLeftSidebarWidth] = useState(() => {
+    if (typeof window === "undefined") {return 260;}
+    const v = window.localStorage.getItem(STORAGE_LEFT);
+    const n = v ? parseInt(v, 10) : NaN;
+    return Number.isFinite(n) ? clamp(n, LEFT_SIDEBAR_MIN, LEFT_SIDEBAR_MAX) : 260;
+  });
+  const [rightSidebarWidth, setRightSidebarWidth] = useState(() => {
+    if (typeof window === "undefined") {return 320;}
+    const v = window.localStorage.getItem(STORAGE_RIGHT);
+    const n = v ? parseInt(v, 10) : NaN;
+    return Number.isFinite(n) ? clamp(n, RIGHT_SIDEBAR_MIN, RIGHT_SIDEBAR_MAX) : 320;
+  });
+  useEffect(() => {
+    window.localStorage.setItem(STORAGE_LEFT, String(leftSidebarWidth));
+  }, [leftSidebarWidth]);
+  useEffect(() => {
+    window.localStorage.setItem(STORAGE_RIGHT, String(rightSidebarWidth));
+  }, [rightSidebarWidth]);
+
   // Derive file context for chat sidebar directly from activePath (stable across loading).
   // Exclude reserved virtual paths (~chats, ~cron, etc.) where file-scoped chat is irrelevant.
   const fileContext = useMemo(() => {
@@ -919,8 +1007,13 @@ function WorkspacePageInner() {
 
   return (
     // eslint-disable-next-line jsx-a11y/click-events-have-key-events, jsx-a11y/no-static-element-interactions
-    <div className="flex h-screen" style={{ background: "var(--color-bg)" }} onClick={handleContainerClick}>
-      {/* Sidebar — static on desktop, drawer overlay on mobile */}
+    <div
+      ref={layoutRef}
+      className="flex h-screen"
+      style={{ background: "var(--color-bg)" }}
+      onClick={handleContainerClick}
+    >
+      {/* Left sidebar — static on desktop (resizable), drawer overlay on mobile */}
       {isMobile ? (
         sidebarOpen && (
           <WorkspaceSidebar
@@ -945,24 +1038,36 @@ function WorkspacePageInner() {
           />
         )
       ) : (
-        <WorkspaceSidebar
-          tree={enhancedTree}
-          activePath={activePath}
-          onSelect={handleNodeSelect}
-          onRefresh={refreshTree}
-          orgName={context?.organization?.name}
-          loading={treeLoading}
-          browseDir={browseDir}
-          parentDir={effectiveParentDir}
-          onNavigateUp={handleNavigateUp}
-          onGoHome={handleGoHome}
-          onFileSearchSelect={handleFileSearchSelect}
-          workspaceRoot={workspaceRoot}
-          onGoToChat={handleGoToChat}
-          onExternalDrop={handleSidebarExternalDrop}
-          activeProfile={activeProfile}
-          onProfileSwitch={handleProfileSwitch}
-        />
+        <>
+          <div className="flex shrink-0 flex-col" style={{ width: leftSidebarWidth }}>
+            <WorkspaceSidebar
+              tree={enhancedTree}
+              activePath={activePath}
+              onSelect={handleNodeSelect}
+              onRefresh={refreshTree}
+              orgName={context?.organization?.name}
+              loading={treeLoading}
+              browseDir={browseDir}
+              parentDir={effectiveParentDir}
+              onNavigateUp={handleNavigateUp}
+              onGoHome={handleGoHome}
+              onFileSearchSelect={handleFileSearchSelect}
+              workspaceRoot={workspaceRoot}
+              onGoToChat={handleGoToChat}
+              onExternalDrop={handleSidebarExternalDrop}
+              activeProfile={activeProfile}
+              onProfileSwitch={handleProfileSwitch}
+              width={leftSidebarWidth}
+            />
+          </div>
+          <ResizeHandle
+            mode="left"
+            containerRef={layoutRef}
+            min={LEFT_SIDEBAR_MIN}
+            max={LEFT_SIDEBAR_MAX}
+            onResize={setLeftSidebarWidth}
+          />
+        </>
       )}
 
       {/* Main content */}
@@ -1127,26 +1232,38 @@ function WorkspacePageInner() {
                   />
                 )
               ) : (
-                <ChatSessionsSidebar
-                  sessions={sessions}
-                  activeSessionId={activeSessionId}
-                  activeSessionTitle={activeSessionTitle}
-                  streamingSessionIds={streamingSessionIds}
-                  subagents={subagents}
-                  activeSubagentKey={activeSubagentKey}
-                  onSelectSession={(sessionId) => {
-                    setActiveSessionId(sessionId);
-                    setActiveSubagentKey(null);
-                    void chatRef.current?.loadSession(sessionId);
-                  }}
-                  onNewSession={() => {
-                    setActiveSessionId(null);
-                    setActiveSubagentKey(null);
-                    void chatRef.current?.newSession();
-                    router.replace("/workspace", { scroll: false });
-                  }}
-                  onSelectSubagent={handleSelectSubagent}
-                />
+                <>
+                  <ResizeHandle
+                    mode="right"
+                    containerRef={layoutRef}
+                    min={RIGHT_SIDEBAR_MIN}
+                    max={RIGHT_SIDEBAR_MAX}
+                    onResize={setRightSidebarWidth}
+                  />
+                  <div className="flex shrink-0 flex-col" style={{ width: rightSidebarWidth }}>
+                    <ChatSessionsSidebar
+                      sessions={sessions}
+                      activeSessionId={activeSessionId}
+                      activeSessionTitle={activeSessionTitle}
+                      streamingSessionIds={streamingSessionIds}
+                      subagents={subagents}
+                      activeSubagentKey={activeSubagentKey}
+                      onSelectSession={(sessionId) => {
+                        setActiveSessionId(sessionId);
+                        setActiveSubagentKey(null);
+                        void chatRef.current?.loadSession(sessionId);
+                      }}
+                      onNewSession={() => {
+                        setActiveSessionId(null);
+                        setActiveSubagentKey(null);
+                        void chatRef.current?.newSession();
+                        router.replace("/workspace", { scroll: false });
+                      }}
+                      onSelectSubagent={handleSelectSubagent}
+                      width={rightSidebarWidth}
+                    />
+                  </div>
+                </>
               )}
             </>
           ) : (
@@ -1176,21 +1293,30 @@ function WorkspacePageInner() {
 
               {/* Chat sidebar (file/folder-scoped) — hidden for reserved paths, hidden on mobile */}
               {!isMobile && fileContext && showChatSidebar && (
-                <aside
-                  className="flex-shrink-0 border-l"
-                  style={{
-                    width: 380,
-                    borderColor: "var(--color-border)",
-                    background: "var(--color-bg)",
-                  }}
-                >
-                  <ChatPanel
-                    ref={compactChatRef}
-                    compact
-                    fileContext={fileContext}
-                    onFileChanged={handleFileChanged}
+                <>
+                  <ResizeHandle
+                    mode="right"
+                    containerRef={layoutRef}
+                    min={RIGHT_SIDEBAR_MIN}
+                    max={RIGHT_SIDEBAR_MAX}
+                    onResize={setRightSidebarWidth}
                   />
-                </aside>
+                  <aside
+                    className="flex-shrink-0 border-l flex flex-col"
+                    style={{
+                      width: rightSidebarWidth,
+                      borderColor: "var(--color-border)",
+                      background: "var(--color-bg)",
+                    }}
+                  >
+                    <ChatPanel
+                      ref={compactChatRef}
+                      compact
+                      fileContext={fileContext}
+                      onFileChanged={handleFileChanged}
+                    />
+                  </aside>
+                </>
               )}
             </>
           )}