diff --git a/frontend/js/textbook-tracker.js b/frontend/js/textbook-tracker.js
index fdb8f0b..a144bdb 100644
--- a/frontend/js/textbook-tracker.js
+++ b/frontend/js/textbook-tracker.js
@@ -31,26 +31,32 @@
   let syncPending = false;
   let pendingExtra = null;
   function syncToServer(extra) {
-    if (typeof LS === 'undefined' || !LS.getToken || !LS.getToken()) return;
+    if (typeof LS === 'undefined' || !LS.getToken) { console.warn('[tracker] LS не загружен — пропускаем sync'); return; }
+    if (!LS.getToken()) { console.warn('[tracker] нет токена в localStorage — пользователь не залогинен'); return; }
     if (syncPending) {
       pendingExtra = Object.assign(pendingExtra || {}, extra || {});
       return;
     }
     syncPending = true;
+    const body = JSON.stringify({ last_para: localState.last, ...(extra || {}) });
+    console.log('[tracker]', slug, '→ POST', body);
     fetch('/api/textbooks/' + slug + '/progress', {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
         'Authorization': 'Bearer ' + LS.getToken(),
       },
-      body: JSON.stringify({ last_para: localState.last, ...(extra || {}) }),
+      body,
+    }).then(r => {
+      console.log('[tracker]', slug, '← HTTP', r.status);
+      if (!r.ok) r.text().then(t => console.warn('[tracker] ошибка:', t));
     }).finally(() => {
       syncPending = false;
       if (pendingExtra) {
         const next = pendingExtra; pendingExtra = null;
         syncToServer(next);
       }
-    }).catch(() => {});
+    }).catch(e => console.warn('[tracker] fetch упал:', e));
   }
 
   /* ── 2. Initial load: merge server data into local state + push back ──
@@ -224,6 +230,7 @@
       const pill = e.target.closest('.para-pill[data-para]');
       if (!pill) return;
       const key = pill.dataset.para;
+      console.log('[tracker] клик по пилюле', key);
       localState.last = key;
       if (!localState.read.includes(key)) {
         localState.read.push(key);
@@ -456,6 +463,7 @@
   }
 
   function boot() {
+    console.log('[tracker] boot, slug =', slug, '| LS:', typeof LS !== 'undefined', '| token:', typeof LS !== 'undefined' && LS.getToken && !!LS.getToken());
     injectStyles();
     installBackButton();
     installBookmarksBtn();