diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 000000000..d48d9d516
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,31 @@
+# Changelog
+
+All notable changes to Odysseus will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
+
+## [Unreleased]
+
+### Fixed
+
+- **auth: prevent spurious login redirect on mobile during text input**
+  The global `window.fetch` 401 interceptor (`static/app.js`) unconditionally
+  redirected to `/login` on any background API call that returned 401. On mobile,
+  when the user backgrounded the app (switched apps, locked phone), session
+  cookies could become stale. When they returned, background fetches (task
+  notification polling every 30s, calendar refetch on tab resume, notes badge
+  refresh) received 401 responses and triggered an immediate redirect to
+  `/login`, which wiped the user's unsent text input and chat state.
+
+  This was especially noticeable on mobile browsers which aggressively suspend
+  background tabs and expire cookies faster than desktop browsers.
+
+  The fix adds three improvements to the 401 interceptor:
+  1. **Retry once after 2s** — catches transient 401s from stale cookies on
+     mobile tab resume that resolve on retry.
+  2. **Deduplication** — prevents multiple stacked redirects from concurrent
+     background fetches (e.g. task polling + calendar refetch simultaneously
+     hitting 401).
+  3. **Typing guard** — if the user is actively typing in the message input
+     when the redirect fires, it defers until the input loses focus, preserving
+     the draft.
diff --git a/static/app.js b/static/app.js
index 97f0ae77e..381916f78 100644
--- a/static/app.js
+++ b/static/app.js
@@ -185,11 +185,27 @@ function initRailHoverLabels() {
   });
 }
 
-// Redirect to login on 401 from any fetch
+// Redirect to login on 401 from any fetch — but retry once first to avoid
+// spurious redirects on mobile when background tabs resume after cookie staleness.
+// If the user is mid-typing, delay the redirect so their draft isn't wiped.
+let _401Cooldown = false;
 const _origFetch = window.fetch;
 window.fetch = async function(...args) {
   const res = await _origFetch.apply(this, args);
-  if (res.status === 401 && !String(args[0]).includes('/api/auth/')) {
+  if (res.status !== 401 || String(args[0]).includes('/api/auth/')) return res;
+  if (_401Cooldown) return res;
+  _401Cooldown = true;
+  await new Promise(r => setTimeout(r, 2000));
+  try {
+    const retry = await _origFetch.apply(this, args);
+    if (retry.status !== 401) { _401Cooldown = false; return res; }
+  } catch (_) {}
+  const msgInput = document.getElementById('message');
+  const isTyping = msgInput && msgInput === document.activeElement && msgInput.value.trim().length > 0;
+  if (isTyping) {
+    const _onBlur = () => { msgInput.removeEventListener('blur', _onBlur); window.location.href = '/login'; };
+    msgInput.addEventListener('blur', _onBlur);
+  } else {
     window.location.href = '/login';
   }
   return res;