diff --git a/tests/ui/knob_matrix.spec.ts b/tests/ui/knob_matrix.spec.ts
index 39fc173e..7c5a03c2 100644
--- a/tests/ui/knob_matrix.spec.ts
+++ b/tests/ui/knob_matrix.spec.ts
@@ -159,6 +159,31 @@ test("theme picker: every click persists and flips the body class", async ({ pag
   await page.locator('.theme-btn[data-theme="tokyo-night"]').click();
   await back;
   expectNoNewConsoleErrors();
+
+  // THE STRAND-CLASS REGRESSION PIN: the global 401 interceptor can
+  // clear the localStorage bearer (session rotation); theme saves must
+  // ride the token COOKIE (middleware TokenLookup checks cookie first)
+  // — never gated on localStorage ("can no longer change themes",
+  // 2026-10-31: the save early-returned without a bearer and every
+  // reload re-rendered the old server theme).
+  await page.evaluate(() => localStorage.removeItem("token"));
+  await appearance.click();
+  const putNord = page.waitForRequest(
+    (r) => r.method() === "PUT" && r.url().includes("/api/auth/theme"),
+  );
+  await page.locator('.theme-btn[data-theme="nord"]').click();
+  expect((await putNord).postDataJSON()).toEqual({ theme: "nord" });
+  await expect.poll(() => page.locator("body").getAttribute("class")).toContain("theme-nord");
+
+  // Restore the default — also via cookie, proving persistence works
+  // without any localStorage bearer at all.
+  await appearance.click();
+  const putBack = page.waitForRequest(
+    (r) => r.method() === "PUT" && r.url().includes("/api/auth/theme"),
+  );
+  await page.locator('.theme-btn[data-theme="tokyo-night"]').click();
+  await putBack;
+  expectNoNewConsoleErrors();
 });
 
 test("pencil glyph vs card body: modal stays, card navigates", async ({ page }) => {
diff --git a/web/src/admin.ts b/web/src/admin.ts
index 1353d9a2..33cda338 100644
--- a/web/src/admin.ts
+++ b/web/src/admin.ts
@@ -1,5 +1,6 @@
 import { confirmDialog } from "./confirm";
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 import { showToast } from "./toast";
 
 // Admin API calls authenticate with the Bearer token stashed at login,
@@ -7,23 +8,11 @@ import { showToast } from "./toast";
 // web session can still have an empty/stale localStorage token. User-
 // triggered actions must never die silently in that state (the
 // /admin/archived purge + delete buttons were invisible dead-ends: the
-// missing-token return fired before the confirm dialog): requireToken
-// fails loudly instead.
-function requireToken(): string | null {
-  const token = localStorage.getItem("token");
-  if (!token) {
-    showToast("Session expired — sign out and back in, then retry", "error");
-  }
-  return token;
-}
-
 async function scanAllLibraries(): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
 
   try {
     const libsResp = await fetch("/api/libraries", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (!libsResp.ok) {
@@ -46,7 +35,7 @@ async function scanAllLibraries(): Promise<void> {
       const scanResp = await fetch(`/api/libraries/${lib.id}/scan`, {
         method: "POST",
         headers: {
-          Authorization: `Bearer ${token}`,
+
           "Content-Type": "application/json",
         },
         body: JSON.stringify({ force: true }),
@@ -125,7 +114,6 @@ function showScanProgress(jobIds: string[], libraryNames: Record<string, string>
 let scanPollInterval: ReturnType<typeof setInterval> | undefined = undefined;
 
 function pollScanProgress(jobIds: string[], _libraryNames: Record<string, string>): void {
-  const token = localStorage.getItem("token");
   const startTime = Date.now();
   const cancelledJobs = new Set<string>();
 
@@ -140,7 +128,7 @@ function pollScanProgress(jobIds: string[], _libraryNames: Record<string, string
     for (const jobId of jobIds) {
       try {
         const resp = await fetch(`/api/scanner/status/${jobId}`, {
-          headers: { Authorization: `Bearer ${token}` },
+          headers: authHeaders(),
         });
 
         if (resp.ok) {
@@ -241,8 +229,6 @@ function updateLibraryProgress(jobId: string, status: any): void {
 // aborts the walk at its next context check and skips the archive pass,
 // so cancelling never archives unvisited files.
 async function cancelScan(jobId: string): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
 
   const btn = document.querySelector<HTMLButtonElement>(`[data-cancel-job="${jobId}"]`);
   if (btn) {
@@ -253,7 +239,7 @@ async function cancelScan(jobId: string): Promise<void> {
   try {
     const resp = await fetch(`/api/scanner/cancel/${jobId}`, {
       method: "POST",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) {
       const err = await resp.json().catch(() => ({}));
@@ -273,12 +259,10 @@ async function cancelScan(jobId: string): Promise<void> {
 // list so it also covers jobs this page never started (e.g. started
 // before a refresh), then cancels each one.
 async function cancelAllScans(): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
 
   try {
     const resp = await fetch("/api/scanner/active", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) {
       throw new Error("Failed to list active scans");
@@ -303,13 +287,10 @@ function setCancelAllVisible(visible: boolean): void {
 // widget and re-attach polling. Websocket start-events only reach pages
 // that were already open when the scan began.
 async function checkActiveScans(): Promise<void> {
-  // Passive page-load probe, not a user action: stay silent when the API
-  // token is absent (requireToken's toast would fire on every page visit).
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // Passive page-load probe, not a user action — cookie auth carries it.
   try {
     const resp = await fetch("/api/scanner/active", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) return;
     const data = await resp.json();
@@ -323,7 +304,7 @@ async function checkActiveScans(): Promise<void> {
     const libraryNames: Record<string, string> = {};
     try {
       const libsResp = await fetch("/api/libraries", {
-        headers: { Authorization: `Bearer ${token}` },
+        headers: authHeaders(),
       });
       if (libsResp.ok) {
         const libsData = await libsResp.json();
@@ -389,13 +370,10 @@ function hideScanProgress(): void {
 async function loadWatchStatus(): Promise<void> {
   // Passive status fetch inside the admin component's init, not a user
   // action: stay silent when the API token is absent (requireToken's
-  // toast would fire on every page visit).
-  const token = localStorage.getItem("token");
-  if (!token) return;
 
   try {
     const response = await fetch("/api/scanner/watch/status", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (response.ok) {
       const data = await response.json();
@@ -420,8 +398,6 @@ function stopScanStatusPolling(): void {
 // window for the library admin page's inline button; reading history is
 // deleted with the rows, so a confirm dialog guards it.
 async function purgeArchivedItems(): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
 
   if (
     !(await confirmDialog(
@@ -434,7 +410,7 @@ async function purgeArchivedItems(): Promise<void> {
   try {
     const resp = await fetch("/api/media-items/purge-archived", {
       method: "POST",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) {
       const err = await resp.json().catch(() => ({}));
@@ -452,12 +428,10 @@ async function purgeArchivedItems(): Promise<void> {
 // its file to return (POST /api/media-items/:id/unarchive). If the file is
 // still gone the next scan hides it again.
 async function unarchiveItem(id: string): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
   try {
     const resp = await fetch(`/api/media-items/${id}/unarchive`, {
       method: "POST",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) {
       const err = await resp.json().catch(() => ({}));
@@ -473,8 +447,6 @@ async function unarchiveItem(id: string): Promise<void> {
 // Permanently delete one archived item and its reading history
 // (DELETE /api/media-items/:id).
 async function deleteArchivedItem(id: string): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
   if (
     !(await confirmDialog(
       "Permanently delete this item? Its reading progress, notes, and highlights will be lost.",
@@ -485,7 +457,7 @@ async function deleteArchivedItem(id: string): Promise<void> {
   try {
     const resp = await fetch(`/api/media-items/${id}`, {
       method: "DELETE",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (!resp.ok) {
       const err = await resp.json().catch(() => ({}));
@@ -502,8 +474,6 @@ async function deleteArchivedItem(id: string): Promise<void> {
 // same content hash (POST /api/media-items/:id/merge), then remove the
 // archived entry. Covers copy-then-delete-later moves between libraries.
 async function mergeArchivedItem(sourceId: string, targetId: string): Promise<void> {
-  const token = requireToken();
-  if (!token) return;
   if (
     !(await confirmDialog(
       "Merge this archived copy's reading progress, notes, and highlights into the active copy? The archived entry is removed.",
@@ -514,10 +484,7 @@ async function mergeArchivedItem(sourceId: string, targetId: string): Promise<vo
   try {
     const resp = await fetch(`/api/media-items/${sourceId}/merge`, {
       method: "POST",
-      headers: {
-        Authorization: `Bearer ${token}`,
-        "Content-Type": "application/json",
-      },
+      headers: { ...authHeaders(), "Content-Type": "application/json" },
       body: JSON.stringify({ target_id: targetId }),
     });
     if (!resp.ok) {
diff --git a/web/src/bookPicker.ts b/web/src/bookPicker.ts
index caf78052..c99a2ac7 100644
--- a/web/src/bookPicker.ts
+++ b/web/src/bookPicker.ts
@@ -1,6 +1,7 @@
 // Book Picker for Collections - multi-select book picker modal
 // CRITICAL: Selection state must persist across HTMX grid updates
 
+import { authHeaders } from "./storage";
 import { Alpine } from "./alpine";
 import { showToast } from "./toast";
 
@@ -80,11 +81,6 @@ Alpine.store("bookPicker", {
   },
 
   async submit() {
-    const token = localStorage.getItem("token");
-    if (!token) {
-      showToast("Not authenticated", "error");
-      return;
-    }
 
     if (this.selectedBooks.size === 0) {
       showToast("No books selected", "error");
@@ -99,8 +95,8 @@ Alpine.store("bookPicker", {
       const response = await fetch(`/api/collections/${collectionId}/books`, {
         method: "POST",
         headers: {
+          ...authHeaders(),
           "Content-Type": "application/json",
-          Authorization: `Bearer ${token}`,
         },
         body: JSON.stringify({
           book_ids: Array.from(this.selectedBooks),
diff --git a/web/src/bookshelf.ts b/web/src/bookshelf.ts
index 76aa52be..4e5b3b08 100644
--- a/web/src/bookshelf.ts
+++ b/web/src/bookshelf.ts
@@ -1,5 +1,6 @@
 // Bookshelf functionality - procedural/imperative style
 
+import { authHeaders } from "./storage";
 import { Alpine } from "./alpine";
 import { showToast } from "./toast";
 import type { FilterGroupState, FilterRuleState } from "./filter_builder";
@@ -183,11 +184,6 @@ Alpine.data("bookshelf", () => ({
   // The qf engine then drives it everywhere — shelf, collections page,
   // play chains — with zero re-authoring.
   async saveFilterAsCollection() {
-    const token = localStorage.getItem("token");
-    if (!token) {
-      showToast("Not authenticated", "error");
-      return;
-    }
     const nameInput = document.getElementById("save-filter-name") as HTMLInputElement | null;
     const name = nameInput?.value?.trim() ?? "";
     if (!name) {
@@ -203,7 +199,7 @@ Alpine.data("bookshelf", () => ({
     try {
       const response = await fetch("/api/collections", {
         method: "POST",
-        headers: { "Content-Type": "application/json", Authorization: `Bearer ${token}` },
+        headers: { ...authHeaders(), "Content-Type": "application/json" },
         body: JSON.stringify({ name, filter_tree: tree }),
       });
       if (response.ok) {
@@ -231,16 +227,11 @@ Alpine.data("bookshelf", () => ({
 
     showToast(`Loading filter: ${filterName}...`, "info");
 
-    const token = localStorage.getItem("token");
-    if (!token) {
-      showToast("Not authenticated", "error");
-      return;
-    }
 
     try {
       // Fetch filter details from API
       const response = await fetch(`/api/saved-filters/${filterId}`, {
-        headers: { Authorization: `Bearer ${token}` },
+        headers: authHeaders(),
       });
 
       if (!response.ok) {
@@ -320,16 +311,11 @@ Alpine.data("bookshelf", () => ({
 
     if (!confirm("Are you sure you want to delete this filter?")) return;
 
-    const token = localStorage.getItem("token");
-    if (!token) {
-      showToast("Not authenticated", "error");
-      return;
-    }
 
     try {
       const response = await fetch(`/api/saved-filters/${filterId}`, {
         method: "DELETE",
-        headers: { Authorization: `Bearer ${token}` },
+        headers: authHeaders(),
       });
 
       if (response.ok) {
diff --git a/web/src/collection-rules.ts b/web/src/collection-rules.ts
index 94636058..7df7ab38 100644
--- a/web/src/collection-rules.ts
+++ b/web/src/collection-rules.ts
@@ -8,6 +8,7 @@
 // arrays preload as their CONVERTED tree (RulesToFilterTree, rendered
 // server-side) and upgrade at the first Apply.
 
+import { authHeaders } from "./storage";
 import { Alpine } from "./alpine";
 import { showToast } from "./toast";
 
@@ -22,11 +23,6 @@ function initCollectionRules(id: string, _scope: string, _treeJSON: string): voi
   // absent at init timing.
   Alpine.store("collectionTreeApply", {
     hook: async (wire: string) => {
-      const token = localStorage.getItem("token");
-      if (!token) {
-        showToast("Not authenticated", "error");
-        return;
-      }
       const name = pageCollectionName();
       if (!name) {
         showToast("Cannot determine the collection name", "error");
@@ -35,7 +31,7 @@ function initCollectionRules(id: string, _scope: string, _treeJSON: string): voi
       try {
         const response = await fetch(`/api/collections/${collectionId}`, {
           method: "PUT",
-          headers: { "Content-Type": "application/json", Authorization: `Bearer ${token}` },
+          headers: { ...authHeaders(), "Content-Type": "application/json" },
           body: JSON.stringify({ name, filter_tree: JSON.parse(wire) }),
         });
         if (response.ok) {
diff --git a/web/src/collections.ts b/web/src/collections.ts
index d4eb4458..9232826c 100644
--- a/web/src/collections.ts
+++ b/web/src/collections.ts
@@ -1,4 +1,5 @@
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 import { showToast } from "./toast";
 import { createWebSocket } from "./websocket";
 import { initLibrarySwitcher, switchWithTransition } from "./library-switcher";
@@ -50,7 +51,9 @@ function initializeCollectionWebSocket(): void {
 function setupHTMXAuth(): void {
   document.body.addEventListener("htmx:configRequest", function (evt: Event) {
     const token = localStorage.getItem("token");
-    (evt as any).detail.headers["Authorization"] = `Bearer ${token}`;
+    // Only attach a bearer when localStorage has one — htmx sends
+    // cookies regardless, and "Bearer null" is never needed.
+    if (token) (evt as any).detail.headers["Authorization"] = `Bearer ${token}`;
   });
 }
 
@@ -299,12 +302,10 @@ function toggleSelection(this: any, id: string): void {
 }
 
 async function doRemoveBook(id: string): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
   try {
     const response = await fetch(`/api/collections/${getCollectionId()}/books/${id}`, {
       method: "DELETE",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (response.ok) {
       showToast("Removed from collection", "success");
@@ -318,15 +319,10 @@ async function doRemoveBook(id: string): Promise<void> {
 }
 
 async function doBulkRemove(ids: string[]): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
   try {
     const response = await fetch(`/api/collections/${getCollectionId()}/books/bulk-remove`, {
       method: "POST",
-      headers: {
-        "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
-      },
+      headers: { ...authHeaders(), "Content-Type": "application/json" },
       body: JSON.stringify({ book_ids: ids }),
     });
     if (response.ok) {
@@ -426,16 +422,18 @@ Alpine.data("collections", () => ({
   // setChainOrder — the detail header's listening-order select (plan
   // §10 R2: the collection's chain order is curated HERE, not on the
   // player). Merges into view_settings server-side, then reloads so
-  // the chain producer's stored order takes effect.
+  // the chain producer's stored order takes effect. The save rides
+  // the token COOKIE (middleware cookie:token lookup) — never gate on
+  // localStorage: the 401 interceptor clears it, and a token-gated
+  // early-return would strand the setting (same class as the
+  // changeTheme fix, 2026-10-31).
   setChainOrder(this: any, collectionID: string, order: string) {
     const token = localStorage.getItem("token");
-    if (!token) return;
+    const headers: Record<string, string> = { "Content-Type": "application/json" };
+    if (token) headers.Authorization = "Bearer " + token;
     void fetch("/api/collections/" + collectionID + "/view-settings", {
       method: "PUT",
-      headers: {
-        "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
-      },
+      headers,
       body: JSON.stringify({ chain_order: order }),
     }).then((r) => {
       if (r.ok) {
@@ -496,15 +494,10 @@ async function moveCollectionBook(this: any, mediaId: string, direction: number)
     .map((c) => c.dataset.mediaId)
     .filter((id): id is string => Boolean(id));
 
-  const token = localStorage.getItem("token");
-  if (!token) return;
   try {
     const response = await fetch(`/api/collections/${getCollectionId()}/items/order`, {
       method: "PUT",
-      headers: {
-        Authorization: `Bearer ${token}`,
-        "Content-Type": "application/json",
-      },
+      headers: { ...authHeaders(), "Content-Type": "application/json" },
       body: JSON.stringify({ item_ids: orderedIds }),
     });
     if (!response.ok) {
diff --git a/web/src/conflicts.ts b/web/src/conflicts.ts
index 12a2e217..7509d8be 100644
--- a/web/src/conflicts.ts
+++ b/web/src/conflicts.ts
@@ -1,4 +1,5 @@
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 import { showToast } from "./toast";
 
 async function refreshConflicts(): Promise<void> {
@@ -85,14 +86,12 @@ async function resolveConflict(
   winner: string,
   manualData?: Record<string, unknown>,
 ): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch(`/api/conflicts/${conflictId}/resolve`, {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
       },
       body: JSON.stringify({ winner, manual_data: manualData }),
@@ -115,14 +114,12 @@ async function bulkResolve(
   strategy: "most_recent" | "highest_progress",
   conflictIds: string[],
 ): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch("/api/conflicts/bulk-resolve", {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
       },
       body: JSON.stringify({ conflict_ids: conflictIds, strategy }),
@@ -140,14 +137,12 @@ async function bulkResolve(
 }
 
 async function bulkDismiss(conflictIds: string[]): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch("/api/conflicts/bulk-dismiss", {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
       },
       body: JSON.stringify({ conflict_ids: conflictIds }),
@@ -164,13 +159,12 @@ async function bulkDismiss(conflictIds: string[]): Promise<void> {
 }
 
 async function dismissAllResolved(): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch("/api/conflicts/dismiss-resolved", {
       method: "POST",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
diff --git a/web/src/custom-section-builder.ts b/web/src/custom-section-builder.ts
index 433db06a..faec7a78 100644
--- a/web/src/custom-section-builder.ts
+++ b/web/src/custom-section-builder.ts
@@ -1,3 +1,4 @@
+import { authHeaders } from "./storage";
 import { apiPost } from "./api";
 import { showToast } from "./toast";
 
@@ -377,7 +378,7 @@ async function searchBooks(): Promise<void> {
       `/api/books/search?q=${encodeURIComponent(query)}&library_id=${libraryId}`,
       {
         headers: {
-          Authorization: `Bearer ${localStorage.getItem("token")}`,
+          ...authHeaders(),
           "Content-Type": "application/json",
         },
       },
diff --git a/web/src/dashboard.ts b/web/src/dashboard.ts
index 54687b41..6e210bca 100644
--- a/web/src/dashboard.ts
+++ b/web/src/dashboard.ts
@@ -1,4 +1,5 @@
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 import { apiPost, apiPut } from "./api";
 import { showToast } from "./toast";
 import { initLibrarySwitcher, switchWithTransition } from "./library-switcher";
@@ -22,7 +23,7 @@ async function openDashboardSettings(): Promise<void> {
   // scope — the server returns that row when library_id is absent.
   const query = libraryId ? `?library_id=${encodeURIComponent(libraryId)}` : "";
   const response = await fetch(`/api/dashboard/preferences${query}`, {
-    headers: { Authorization: `Bearer ${localStorage.getItem("token")}` },
+    headers: authHeaders(),
   });
 
   if (response.ok) {
@@ -89,7 +90,7 @@ async function fetchAndRenderSections(libraryId: string): Promise<void> {
   const param = libraryId ? `library_id=${libraryId}` : "";
   const response = await fetch(`/api/dashboard/sections?${param}`, {
     headers: {
-      Authorization: `Bearer ${localStorage.getItem("token")}`,
+      ...authHeaders(),
       "Content-Type": "application/json",
     },
   });
@@ -535,7 +536,7 @@ function initDashboard() {
         const param = libraryId ? `library_id=${libraryId}` : "";
         const response = await fetch(`/api/dashboard/sections?${param}`, {
           headers: {
-            Authorization: `Bearer ${localStorage.getItem("token")}`,
+            ...authHeaders(),
             "Content-Type": "application/json",
           },
         });
diff --git a/web/src/device-management.ts b/web/src/device-management.ts
index 66d000f4..cd98e04a 100644
--- a/web/src/device-management.ts
+++ b/web/src/device-management.ts
@@ -1,6 +1,6 @@
 import { Alpine } from "./alpine";
 import { showToast } from "./toast";
-import { getToken } from "./storage";
+import { authHeaders, getToken } from "./storage";
 
 function getDeviceIcon(typeName: string): string {
   const deviceIcons: Record<string, string> = {
@@ -27,8 +27,7 @@ function hideAddDeviceModal(): void {
 async function handleAddDevice(event: Event): Promise<void> {
   event.preventDefault();
 
-  const token = getToken();
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   const deviceNameInput = document.getElementById("device-name") as HTMLInputElement;
   const deviceTypeInput = document.getElementById("device-type") as HTMLSelectElement;
@@ -47,7 +46,6 @@ async function handleAddDevice(event: Event): Promise<void> {
       method: "POST",
       headers: {
         "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
       },
       body: JSON.stringify(data),
     });
@@ -78,13 +76,12 @@ function showDeviceSettings(deviceId: string): void {
 
   deviceIdInput.value = deviceId;
 
-  const token = getToken();
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   let deviceType: any;
 
   fetch(`/api/devices/${deviceId}`, {
-    headers: { Authorization: `Bearer ${token}` },
+    headers: authHeaders(),
   })
     .then((res) => res.json())
     .then((device) => {
@@ -97,7 +94,7 @@ function showDeviceSettings(deviceId: string): void {
 
       deviceType = device.device_type;
       return fetch("/api/collections", {
-        headers: { Authorization: `Bearer ${token}` },
+        headers: authHeaders(),
       });
     })
     .then((res) => res.json())
@@ -153,7 +150,7 @@ async function loadShelfMappings(deviceId: string): Promise<void> {
 
   try {
     const response = await fetch(`/api/devices/${deviceId}/collections`, {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     const result = await response.json();
 
@@ -233,7 +230,7 @@ async function loadCollections(): Promise<void> {
 
   try {
     const response = await fetch("/api/collections", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     const result = await response.json();
 
@@ -312,7 +309,6 @@ async function handleSaveMapping(event: Event): Promise<void> {
       method: method,
       headers: {
         "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
       },
       body: JSON.stringify(data),
     });
@@ -342,7 +338,7 @@ async function deleteMapping(mappingId: string): Promise<void> {
   try {
     const response = await fetch(`/api/devices/${deviceId}/collections/${mappingId}`, {
       method: "DELETE",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
@@ -412,14 +408,13 @@ async function handleSaveDeviceSettings(event: Event): Promise<void> {
       method: "PUT",
       headers: {
         "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
       },
       body: JSON.stringify(deviceData),
     });
 
     const collectionsRes = await fetch("/api/collections", {
       method: "GET",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     const collections = await collectionsRes.json();
 
@@ -431,8 +426,7 @@ async function handleSaveDeviceSettings(event: Event): Promise<void> {
         method: "PUT",
         headers: {
           "Content-Type": "application/json",
-          Authorization: `Bearer ${token}`,
-        },
+          },
         body: JSON.stringify({
           ...collection,
           view_settings: currentSettings,
@@ -473,7 +467,7 @@ async function handleRevokeDevice(): Promise<void> {
   try {
     const response = await fetch(`/api/devices/${deviceId}`, {
       method: "DELETE",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
@@ -490,13 +484,12 @@ async function handleRevokeDevice(): Promise<void> {
 }
 
 async function approveDevice(registrationId: string): Promise<void> {
-  const token = getToken();
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch(`/api/devices/approve/${registrationId}`, {
       method: "GET",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
@@ -512,13 +505,12 @@ async function approveDevice(registrationId: string): Promise<void> {
 }
 
 async function rejectDevice(registrationId: string): Promise<void> {
-  const token = getToken();
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch(`/api/devices/reject/${registrationId}`, {
       method: "POST",
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
diff --git a/web/src/filter_builder.ts b/web/src/filter_builder.ts
index 00251d23..f4f61200 100644
--- a/web/src/filter_builder.ts
+++ b/web/src/filter_builder.ts
@@ -12,6 +12,7 @@
 // wins server-side.
 
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 
 // ─── operator + field metadata (client mirror of
 // internal/services/filter_registry.go — labels drive the menus) ────
@@ -720,8 +721,7 @@ function filterBuilderData() {
       // other rules (the server answers the blank query with the
       // un-typed top list).
       if (typed.length === 1) return;
-      const token = localStorage.getItem("token");
-      if (!token) return;
+      // cookie auth carries the call; a null bearer must not strand it
       // Open the menu NOW (loading state) — never a blank flash.
       this.suggestions[rowKey] = [];
       this.suggestionsLoading = rowKey;
@@ -741,7 +741,7 @@ function filterBuilderData() {
       params.set("limit", typed ? "8" : "15");
       try {
         const response = await fetch(`/api/media-items/search?${params.toString()}`, {
-          headers: { Authorization: `Bearer ${token}` },
+          headers: authHeaders(),
         });
         if (!response.ok) {
           console.warn(`suggestion fetch failed (${response.status})`);
@@ -792,8 +792,7 @@ function filterBuilderData() {
       }, 350);
     },
     async fetchMatchCount(): Promise<void> {
-      const token = localStorage.getItem("token");
-      if (!token) return;
+      // cookie auth carries the call; a null bearer must not strand it
       // Incomplete rules are NOT filters yet — the count runs on the
       // completed tree only (an incomplete rule would be a 400).
       const completed = this.completedTree(null);
@@ -810,7 +809,7 @@ function filterBuilderData() {
       this.matchCountLoading = true;
       try {
         const response = await fetch(`/api/media-items/filter-count?${params.toString()}`, {
-          headers: { Authorization: `Bearer ${token}` },
+          headers: authHeaders(),
         });
         if (!response.ok) {
           this.matchCount = null;
diff --git a/web/src/header.ts b/web/src/header.ts
index e0132511..74936d87 100644
--- a/web/src/header.ts
+++ b/web/src/header.ts
@@ -12,7 +12,7 @@ import {
   revealCurrentTheme,
   updateWoodPanelingIndicators,
 } from "./theme";
-import { getSelectedLibrary, getRefreshToken, removeRefreshToken } from "./storage";
+import { authHeaders, getSelectedLibrary, getRefreshToken, removeRefreshToken } from "./storage";
 import { addListener, removeListener } from "./websocket";
 
 // Real sign-out: the HttpOnly session cookie can only be cleared by a
@@ -70,10 +70,8 @@ const initializeScanListener = function (this: any) {
   // its next progress tick, so ask the server directly first.
   const restoreActiveScan = async () => {
     try {
-      const token = localStorage.getItem("token");
-      if (!token) return;
       const resp = await fetch("/api/scanner/active-summary", {
-        headers: { Authorization: `Bearer ${token}` },
+        headers: authHeaders(),
       });
       if (!resp.ok) return;
       const data = await resp.json();
diff --git a/web/src/linking.ts b/web/src/linking.ts
index eb78c2ae..56fca4a9 100644
--- a/web/src/linking.ts
+++ b/web/src/linking.ts
@@ -1,13 +1,13 @@
 import { Alpine } from "./alpine";
+import { authHeaders } from "./storage";
 import { showToast } from "./toast";
 
 async function loadUnlinkedBooks(): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch("/api/sync/unlinked-books", {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
@@ -74,14 +74,12 @@ function renderUnlinkedBooks(books: UnlinkedBookData[]): void {
 }
 
 async function linkBook(progressId: string, mediaItemId: string): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch("/api/sync/link-book", {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
       },
       body: JSON.stringify({
@@ -104,8 +102,7 @@ async function linkBook(progressId: string, mediaItemId: string): Promise<void>
 }
 
 async function autoLinkBooks(): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   if (!confirm("Auto-link all books with high confidence matches?")) return;
 
@@ -113,7 +110,6 @@ async function autoLinkBooks(): Promise<void> {
     const response = await fetch("/api/sync/auto-link", {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
       },
       body: JSON.stringify({ confidence_threshold: 0.9 }),
@@ -131,12 +127,11 @@ async function autoLinkBooks(): Promise<void> {
 }
 
 async function getSuggestions(progressId: string): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
+  // cookie auth carries the call; a null bearer must not strand it
 
   try {
     const response = await fetch(`/api/sync/suggestions/${progressId}`, {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
diff --git a/web/src/profile.ts b/web/src/profile.ts
index 301f324f..05fb790c 100644
--- a/web/src/profile.ts
+++ b/web/src/profile.ts
@@ -1,5 +1,5 @@
 import { Alpine } from "./alpine";
-import { removeToken } from "./storage";
+import { authHeaders, removeToken } from "./storage";
 import { showToast } from "./toast";
 
 async function confirmDeleteAccount(): Promise<void> {
@@ -11,18 +11,14 @@ async function confirmDeleteAccount(): Promise<void> {
     return;
   }
 
-  const token = localStorage.getItem("token");
-  if (!token) {
-    window.location.href = "/login";
-    return;
-  }
+  // This page is SSR-gated — reaching this script means authed (the
+  // middleware would have redirected). A localStorage-token check
+  // wrongly bounced cookie-authed users to /login (2026-10-31).
 
   try {
     const response = await fetch("/api/auth/profile", {
       method: "DELETE",
-      headers: {
-        Authorization: `Bearer ${token}`,
-      },
+      headers: authHeaders(),
     });
 
     if (response.ok) {
diff --git a/web/src/stats.ts b/web/src/stats.ts
index c26de780..f52a6e5c 100644
--- a/web/src/stats.ts
+++ b/web/src/stats.ts
@@ -1,3 +1,4 @@
+import { authHeaders } from "./storage";
 import { Alpine } from "./alpine";
 import { showToast } from "./toast";
 import type { ChartConfiguration } from "chart.js";
@@ -213,8 +214,6 @@ function syncUrl(): void {
 // Summary fetch (Reading tab) -----------------------------------------------
 
 async function loadSummary(): Promise<void> {
-  const token = localStorage.getItem("token");
-  if (!token) return;
 
   document.getElementById("stats-empty")?.classList.add("hidden");
   const windowLabel = document.getElementById("stats-window-label");
@@ -222,7 +221,7 @@ async function loadSummary(): Promise<void> {
 
   try {
     const res = await fetch(`/api/stats/summary?range=${encodeURIComponent(currentRange)}`, {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (res.status === 400) {
       const err = await res.json();
@@ -527,10 +526,8 @@ function renderTopBooks(books: TopBook[]): void {
 // Library tab ---------------------------------------------------------------
 
 async function loadLibraries(): Promise<VisibleLibrary[]> {
-  const token = localStorage.getItem("token");
-  if (!token) return [];
   const res = await fetch("/api/libraries/visibility", {
-    headers: { Authorization: `Bearer ${token}` },
+    headers: authHeaders(),
   });
   if (!res.ok) {
     showToast("Failed to load libraries", "error");
@@ -554,8 +551,6 @@ function fillLibrarySelector(rows: VisibleLibrary[]): void {
 
 async function loadLibraryUsage(): Promise<void> {
   if (libraryDataLoaded) return;
-  const token = localStorage.getItem("token");
-  if (!token) return;
   libraryDataLoaded = true;
 
   const qs = currentLibraryID ? `?library_id=${encodeURIComponent(currentLibraryID)}` : "";
@@ -580,7 +575,7 @@ async function loadLibraryUsage(): Promise<void> {
 
   try {
     const res = await fetch(`/api/stats/library-usage${qs}`, {
-      headers: { Authorization: `Bearer ${token}` },
+      headers: authHeaders(),
     });
     if (res.status === 403) {
       showToast("Library not visible to you", "error");
diff --git a/web/src/storage.ts b/web/src/storage.ts
index 5ae0e573..78c1c7b6 100644
--- a/web/src/storage.ts
+++ b/web/src/storage.ts
@@ -39,6 +39,18 @@ function getSelectedLibrary(): string {
   return "";
 }
 
+// Headers for same-origin /api fetches: the localStorage bearer when
+// present, otherwise nothing — the token COOKIE (always sent on
+// same-origin requests) carries auth, since the middleware's
+// TokenLookup checks cookie:token before the header. NEVER gate a
+// call on the bearer's presence: the global 401 interceptor clears
+// localStorage, and token-gated calls then strand every click that
+// should persist ("can no longer change themes", 2026-10-31).
+function authHeaders(): Record<string, string> {
+  const token = localStorage.getItem("token");
+  return token ? { Authorization: `Bearer ${token}` } : {};
+}
+
 function setSelectedLibrary(libraryId: string): void {
   const value = libraryId === "" ? ALL_LIBRARIES : libraryId;
   localStorage.setItem("selectedLibrary", value);
@@ -51,6 +63,7 @@ function clearAll(): void {
 
 export {
   ALL_LIBRARIES,
+  authHeaders,
   clearAll,
   getRefreshToken,
   getSelectedLibrary,
diff --git a/web/src/tag-dropdown.ts b/web/src/tag-dropdown.ts
index 67910817..7876cc1d 100644
--- a/web/src/tag-dropdown.ts
+++ b/web/src/tag-dropdown.ts
@@ -1,3 +1,5 @@
+import { authHeaders } from "./storage";
+
 export interface TagSuggestion {
   value: string;
   count: number;
@@ -9,13 +11,11 @@ export async function searchTagSuggestions(
 ): Promise<TagSuggestion[]> {
   if (!query || query.length < 2 || !libraryId) return [];
 
-  const token = localStorage.getItem("token");
-  if (!token) return [];
 
   try {
     const response = await fetch(
       `/api/media-items/search?tags=${encodeURIComponent(query)}&library_id=${libraryId}&limit=20`,
-      { headers: { Authorization: `Bearer ${token}` } },
+      { headers: authHeaders() },
     );
 
     if (!response.ok) return [];
diff --git a/web/src/theme.ts b/web/src/theme.ts
index d0b39c27..1d541dd1 100644
--- a/web/src/theme.ts
+++ b/web/src/theme.ts
@@ -91,25 +91,28 @@ const changeTheme = async (theme: string): Promise<void> => {
   applyTheme(theme);
   updateThemeIndicators();
 
-  // Save to server if logged in
+  // Save to server. The /api middleware accepts cookie:token OR the
+  // bearer header — the global fetch interceptor wipes localStorage on
+  // any 401, which previously made a token-gated early-return strand
+  // theme persistence forever (reloads re-rendered the old server
+  // theme — "can no longer change themes", 2026-10-31). The cookie
+  // carries the PUT on its own; the bearer is only a bonus header.
   const token = localStorage.getItem(TOKEN_STORAGE_KEY);
-  if (!token) return;
+  const headers: Record<string, string> = { "Content-Type": "application/json" };
+  if (token) headers.Authorization = `Bearer ${token}`;
 
   try {
     const response = await fetch("/api/auth/theme", {
       method: "PUT",
-      headers: {
-        "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
-      },
+      headers,
       body: JSON.stringify({ theme }),
     });
 
     if (!response.ok) {
-      console.log("Theme save failed");
+      console.warn("Theme save failed:", response.status);
     }
   } catch (error) {
-    console.log("Theme save failed", error);
+    console.warn("Theme save failed", error);
   }
 };