fix(webui): persist large sidebar ordering state

webui/src/hooks/useSidebarState.ts

@@ -1,10 +1,7 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 
 import { useClient } from "@/providers/ClientProvider";
-import {
-  fetchSidebarState,
-  updateSidebarState as persistSidebarState,
-} from "@/lib/api";
+import { fetchSidebarState } from "@/lib/api";
 import type { ChatSummary, SidebarStatePayload } from "@/lib/types";
 
 export const DEFAULT_SIDEBAR_STATE: SidebarStatePayload = {
@@ -144,10 +141,9 @@ export function useSidebarState(
     updater: (state: SidebarStatePayload) => SidebarStatePayload,
   ) => Promise<void>;
 } {
-  const { token } = useClient();
+  const { client, token } = useClient();
   const tokenRef = useRef(token);
   const stateRef = useRef(DEFAULT_SIDEBAR_STATE);
-  const persistVersionRef = useRef(0);
   const [state, setState] = useState<SidebarStatePayload>(DEFAULT_SIDEBAR_STATE);
   const [loading, setLoading] = useState(true);
   tokenRef.current = token;
@@ -178,23 +174,11 @@ export function useSidebarState(
   const update = useCallback(
     async (updater: (current: SidebarStatePayload) => SidebarStatePayload) => {
       const next = normalizeSidebarState(updater(stateRef.current));
-      const version = persistVersionRef.current + 1;
-      persistVersionRef.current = version;
       stateRef.current = next;
       setState(next);
-      try {
-        const persisted = normalizeSidebarState(
-          await persistSidebarState(tokenRef.current, next),
-        );
-        if (persistVersionRef.current !== version) return;
-        stateRef.current = persisted;
-        setState(persisted);
-      } catch {
-        // Keep the optimistic UI state. Older gateways or transient auth expiry
-        // should not break the chat list; the next refresh can try again.
-      }
+      client.setSidebarState(next);
     },
-    [],
+    [client],
   );
 
   const pruned = useMemo(() => {

webui/src/lib/nanobot-client.ts

@@ -6,6 +6,7 @@ import type {
   OutboundMcpPresetMention,
   OutboundMedia,
   SessionMention,
+  SidebarStatePayload,
   GoalStateWsPayload,
   WorkspaceScopePayload,
 } from "./types";
@@ -870,6 +871,10 @@ export class NanobotClient {
     });
   }
 
+  setSidebarState(state: SidebarStatePayload): void {
+    this.queueSend({ type: "set_sidebar_state", state });
+  }
+
   // -- internals ---------------------------------------------------------
 
   private setStatus(status: ConnectionStatus): void {

webui/src/lib/types.ts

@@ -1340,6 +1340,7 @@ export type Outbound =
   | { type: "new_chat"; workspace_scope?: WorkspaceScopePayload }
   | { type: "fork_chat"; source_chat_id: string; before_user_index: number; title?: string }
   | { type: "attach"; chat_id: string }
+  | { type: "set_sidebar_state"; state: SidebarStatePayload }
   | { type: "set_workspace_scope"; chat_id: string; workspace_scope: WorkspaceScopePayload }
   | { type: "transcribe_audio"; request_id: string; data_url: string; duration_ms?: number }
   | {

webui/src/tests/app-layout.test.tsx

@@ -13,6 +13,7 @@ const getSessionAutomationsSpy = vi.fn<(key: string) => Promise<SessionAutomatio
 const toggleThemeSpy = vi.fn();
 const updateUrlSpy = vi.fn();
 const attachSpy = vi.fn();
+const setSidebarStateSpy = vi.fn();
 const runStatusHandlers = new Set<(chatId: string, startedAt: number | null) => void>();
 const sessionUpdateHandlers = new Set<(chatId: string, scope?: string) => void>();
 let mockSessions: ChatSummary[] = [];
@@ -218,6 +219,7 @@ vi.mock("@/lib/nanobot-client", () => {
     sendMessage = vi.fn();
     newChat = vi.fn();
     attach = attachSpy;
+    setSidebarState = setSidebarStateSpy;
     close = vi.fn();
     updateUrl = updateUrlSpy;
     updateMaxFrameBytes = vi.fn();
@@ -245,6 +247,7 @@ describe("App layout", () => {
     getSessionAutomationsSpy.mockReset().mockResolvedValue([]);
     toggleThemeSpy.mockReset();
     attachSpy.mockReset();
+    setSidebarStateSpy.mockReset();
     runStatusHandlers.clear();
     sessionUpdateHandlers.clear();
     window.history.replaceState(null, "", "/");
@@ -1403,13 +1406,6 @@ describe("App layout", () => {
         if (href === "/api/webui/sidebar-state") {
           return { ok: true, json: async () => initialState };
         }
-        if (href.startsWith("/api/webui/sidebar-state/update?")) {
-          const encoded = new URLSearchParams(href.split("?", 2)[1]).get("state");
-          return {
-            ok: true,
-            json: async () => JSON.parse(encoded ?? "{}"),
-          };
-        }
         return { ok: false, status: 404 };
       }),
     );
@@ -1429,12 +1425,11 @@ describe("App layout", () => {
       expect(within(sidebar).getByText("Archived")).toBeInTheDocument(),
     );
     expect(within(sidebar).getByRole("button", { name: /^First chat$/ })).toBeInTheDocument();
-    const updateUrl = vi.mocked(fetch).mock.calls
-      .map(([url]) => String(url))
-      .find((url) => url.startsWith("/api/webui/sidebar-state/update?"));
-    expect(updateUrl).toBeTruthy();
-    const encoded = new URLSearchParams(updateUrl?.split("?", 2)[1]).get("state");
-    expect(JSON.parse(encoded ?? "{}").view.show_archived).toBe(true);
+    expect(setSidebarStateSpy).toHaveBeenCalledWith(
+      expect.objectContaining({
+        view: expect.objectContaining({ show_archived: true }),
+      }),
+    );
 
     expect(within(sidebar).queryByRole("button", { name: "View" })).not.toBeInTheDocument();
   });

webui/src/tests/nanobot-client.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
 import { NanobotClient } from "@/lib/nanobot-client";
+import type { SidebarStatePayload } from "@/lib/types";
 
 /**
  * Minimal fake WebSocket implementing the subset NanobotClient touches.
@@ -935,6 +936,44 @@ describe("NanobotClient", () => {
     expect(client.hasUnsettledRun("chat-scope-control")).toBe(true);
   });
 
+  it("sends large sidebar ordering state outside the HTTP request line", () => {
+    const client = new NanobotClient({
+      url: "ws://test",
+      reconnect: false,
+      socketFactory: (url) => new FakeSocket(url) as unknown as WebSocket,
+    });
+    const sessionOrder = Array.from(
+      { length: 160 },
+      (_, index) => `websocket:${index.toString().padStart(4, "0")}-${"x".repeat(48)}`,
+    );
+    const state: SidebarStatePayload = {
+      schema_version: 1,
+      pinned_keys: [],
+      archived_keys: [],
+      session_order: sessionOrder,
+      title_overrides: {},
+      project_name_overrides: {},
+      tags_by_key: {},
+      collapsed_groups: {},
+      view: {
+        density: "comfortable",
+        show_previews: false,
+        show_timestamps: false,
+        show_archived: false,
+        sort: "manual",
+      },
+      updated_at: null,
+    };
+
+    client.connect();
+    lastSocket().fakeOpen();
+    client.setSidebarState(state);
+
+    const [serialized] = lastSocket().sent;
+    expect(new TextEncoder().encode(serialized).byteLength).toBeGreaterThan(8_192);
+    expect(JSON.parse(serialized)).toEqual({ type: "set_sidebar_state", state });
+  });
+
   it("does not correlate a new-chat scope rejection to an unrelated sent turn", async () => {
     const client = new NanobotClient({
       url: "ws://test",