feat: add opt-in session jump buttons

api/config.py

@@ -3682,6 +3682,7 @@ _SETTINGS_DEFAULTS = {
     "theme": "dark",  # light | dark | system
     "skin": "default",  # accent color skin: default | ares | mono | slate | poseidon | sisyphus | charizard
     "font_size": "default",  # small | default | large
+    "session_jump_buttons": False,  # show Start/End transcript jump pills
     "language": "en",  # UI locale code; must match a key in static/i18n.js LOCALES
     "bot_name": os.getenv(
         "HERMES_WEBUI_BOT_NAME", "Hermes"
@@ -3810,6 +3811,7 @@ _SETTINGS_BOOL_KEYS = {
     "show_thinking",
     "simplified_tool_calling",
     "api_redact_enabled",
+    "session_jump_buttons",
 }
 # Language codes are validated as short alphanumeric BCP-47-like tags (e.g. 'en', 'zh', 'fr')
 _SETTINGS_LANG_RE = __import__("re").compile(r"^[a-zA-Z]{2,10}(-[a-zA-Z0-9]{2,8})?$")

static/boot.js

@@ -1308,6 +1308,7 @@ function applyBotName(){
     // Persist default workspace so the blank new-chat page can show it
     // and workspace actions (New file/folder) work before the first session (#804).
     if(s.default_workspace) S._profileDefaultWorkspace=s.default_workspace;
+    window._sessionJumpButtonsEnabled=!!s.session_jump_buttons;
     const appearance=_normalizeAppearance(s.theme,s.skin);
     localStorage.setItem('hermes-theme',appearance.theme);
     _applyTheme(appearance.theme);
@@ -1335,6 +1336,7 @@ function applyBotName(){
     window._notificationsEnabled=false;
     window._showThinking=true;
     window._simplifiedToolCalling=true;
+    window._sessionJumpButtonsEnabled=false;
     window._sidebarDensity='compact';
     window._busyInputMode='queue';
     window._botName='Hermes';

static/i18n.js

@@ -125,6 +125,10 @@ const LOCALES = {
     untitled: 'Untitled',
     n_messages: (n) => `${n} messages`,
     load_older_messages: '↑ Scroll up or click to load older messages',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Sends after response',
     queued_count: (n) => n === 1 ? '1 queued' : `${n} queued`,
     queued_cancel: 'Cancel queued message',
@@ -421,6 +425,8 @@ const LOCALES = {
     settings_update_check_failed: 'Update check failed',
     settings_label_workspace_panel_open: 'Keep workspace panel open by default',
     settings_desc_workspace_panel_open: 'When enabled, the workspace / file browser panel opens automatically with each new session. You can still close it manually at any time.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: 'Open in browser',
     settings_dropdown_conversation: 'Conversation',
     settings_dropdown_appearance: 'Appearance',
@@ -1146,6 +1152,10 @@ const LOCALES = {
     untitled: '無題',
     n_messages: (n) => `${n} 件のメッセージ`,
     load_older_messages: '↑ 上にスクロール、またはクリックして過去のメッセージを読み込む',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: '応答後に送信',
     queued_count: (n) => `${n} 件キュー中`,
     queued_cancel: 'キューに入れたメッセージをキャンセル',
@@ -1442,6 +1452,8 @@ const LOCALES = {
     settings_updates_disabled: 'アップデート確認は無効です',
     settings_label_workspace_panel_open: 'ワークスペースパネルをデフォルトで開いておく',
     settings_desc_workspace_panel_open: '有効にすると、新しいセッションごとにワークスペース/ファイルブラウザパネルが自動で開きます。手動でいつでも閉じられます。',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: 'ブラウザで開く',
     settings_dropdown_conversation: '会話',
     settings_dropdown_appearance: '外観',
@@ -2145,6 +2157,10 @@ const LOCALES = {
     untitled: 'Без названия',
     n_messages: (n) => `${n} сообщений`,
     load_older_messages: '↑ Прокрутите вверх или нажмите, чтобы загрузить ранние сообщения',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Отправить после ответа',
     queued_count: (n) => n === 1 ? '1 в очереди' : `${n} в очереди`,
     queued_cancel: 'Отменить сообщение',
@@ -2880,6 +2896,8 @@ const LOCALES = {
     settings_update_check_failed: 'Ошибка проверки обновлений',
     settings_label_workspace_panel_open: 'Открывать панель рабочей области по умолчанию',
     settings_desc_workspace_panel_open: 'При включении панель файлов будет открываться автоматически в каждой новой сессии.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: 'Открыть в браузере',
     settings_section_system_title: 'System',
     settings_tab_appearance: 'Appearance',
@@ -3102,6 +3120,10 @@ const LOCALES = {
     untitled: 'Sin título',
     n_messages: (n) => `${n} mensajes`,
     load_older_messages: '↑ Desplázate hacia arriba o haz clic para cargar mensajes anteriores',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Enviar después de la respuesta',
     queued_count: (n) => n === 1 ? '1 en cola' : `${n} en cola`,
     queued_cancel: 'Cancelar mensaje en cola',
@@ -3823,6 +3845,8 @@ const LOCALES = {
     settings_update_check_failed: 'Error al comprobar actualizaciones',
     settings_label_workspace_panel_open: 'Mantener panel de espacio abierto',
     settings_desc_workspace_panel_open: 'Al activar, el panel de archivos se abre automáticamente en cada nueva sesión. Aún puedes cerrarlo manualmente.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: 'Abrir en el navegador',
     settings_section_system_title: 'System',
     settings_tab_appearance: 'Appearance',
@@ -4055,6 +4079,10 @@ const LOCALES = {
     untitled: 'Unbenannt',
     n_messages: (n) => `${n} Nachrichten`,
     load_older_messages: '↑ Nach oben scrollen oder klicken, um ältere Nachrichten zu laden',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Wird nach Antwort gesendet',
     queued_count: (n) => n === 1 ? '1 in Warteschlange' : `${n} in Warteschlange`,
     queued_cancel: 'Nachricht abbrechen',
@@ -4511,6 +4539,8 @@ const LOCALES = {
     settings_update_check_failed: 'Update-Prüfung fehlgeschlagen',
     settings_label_workspace_panel_open: 'Arbeitsbereich-Panel standardmäßig öffnen',
     settings_desc_workspace_panel_open: 'Wenn aktiviert, wird der Datei-Browser bei jeder neuen Sitzung automatisch geöffnet. Er kann jederzeit manuell geschlossen werden.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
 
     workspace_drag_hint: 'Ziehen zum Neuordnen',
     workspace_reorder_failed: 'Neuordnen fehlgeschlagen',
@@ -5012,6 +5042,10 @@ const LOCALES = {
     untitled: '\u672a\u547d\u540d',
     n_messages: (n) => `${n} \u6761\u6d88\u606f`,
     load_older_messages: '↑ 向上滚动或点击加载更早的消息',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: '响应后发送',
     queued_count: (n) => n === 1 ? '1 条排队' : `${n} 条排队`,
     queued_cancel: '取消排队消息',
@@ -5730,6 +5764,8 @@ const LOCALES = {
     settings_update_check_failed: '更新检查失败',
     settings_label_workspace_panel_open: '默认保持工作区面板打开',
     settings_desc_workspace_panel_open: '启用后，工作区/文件浏览器面板会在每次新会话时自动打开。您仍可随时手动关闭。',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: '在浏览器中打开',
     settings_section_system_title: 'System',
     settings_tab_appearance: 'Appearance',
@@ -5964,6 +6000,10 @@ const LOCALES = {
     untitled: '\u672a\u547d\u540d',
     n_messages: (n) => `${n} \u689d\u8a0a\u606f`,
     load_older_messages: '↑ 向上捲動或點擊以載入較早的訊息',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     model_unavailable: '\uff08\u4e0d\u53ef\u7528\uff09',
     model_unavailable_title: '\u6b64\u6a21\u578b\u5df2\u7d93\u4e0d\u5728\u7576\u524d provider \u5217\u8868\u4e2d',
     provider_mismatch_warning: (m,p)=>`\"${m}\" \u53ef\u80fd\u7121\u6cd5\u5728\u7576\u524d\u914d\u7f6e\u7684\u63d0\u4f9b\u8005 (${p}) \u4e0b\u904b\u4f5c\u3002\u5c1a\u9001\uff0c\u6216\u5728\u7d42\u7aef\u57f7\u884c \`hermes model\` \u5207\u63db\u3002`,
@@ -6136,6 +6176,8 @@ const LOCALES = {
     settings_update_check_failed: '更新檢查失敗',
     settings_label_workspace_panel_open: '預設保持工作區面板開啓',
     settings_desc_workspace_panel_open: '啟用後，工作區/檔案瀏覽器面板會在每次新會話時自動開啓。您仍可隨時手動關閉。',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: '在瀏覽器中開啓',
     settings_dropdown_conversation: '對話',
     settings_dropdown_appearance: '外觀',
@@ -6288,6 +6330,10 @@ const LOCALES = {
     downloading: (filename) => `正在下載 ${filename}…`,
     n_messages: (n) => `${n} 則訊息`,
     load_older_messages: '↑ 向上捲動或點擊以載入較早的訊息',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     onboarding_api_key_help_prefix: '\u900f\u904e\u4ee5\u4e0b\u65b9\u5f0f\u5132\u5b58\u70ba Hermes .env \u6a94\u6848\u4e2d\u7684\u6a5f\u5bc6',
     onboarding_api_key_label: 'API \u91d1\u9470',
     onboarding_api_key_placeholder: '\u7559\u7a7a\u4ee5\u4fdd\u7559\u5df2\u5132\u5b58\u7684\u91d1\u9470',
@@ -6906,6 +6952,10 @@ const LOCALES = {
     untitled: 'Sem título',
     n_messages: (n) => `${n} mensagens`,
     load_older_messages: '↑ Role para cima ou clique para carregar mensagens mais antigas',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Envia após a resposta',
     queued_count: (n) => n === 1 ? '1 na fila' : `${n} na fila`,
     queued_cancel: 'Cancelar mensagem na fila',
@@ -7170,6 +7220,8 @@ const LOCALES = {
     settings_update_check_failed: 'Falha ao verificar updates',
     settings_label_workspace_panel_open: 'Manter painel workspace aberto por padrão',
     settings_desc_workspace_panel_open: 'Quando ativo, o painel workspace abre automaticamente com cada nova sessão.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: 'Abrir no navegador',
     settings_dropdown_conversation: 'Conversa',
     settings_dropdown_appearance: 'Aparência',
@@ -7802,6 +7854,10 @@ const LOCALES = {
     untitled: '제목 없음',
     n_messages: (n) => `${n}개 메시지`,
     load_older_messages: '↑ 위로 스크롤하거나 클릭하여 이전 메시지 불러오기',
+    session_jump_start: 'Start',
+    session_jump_start_label: 'Jump to beginning of session',
+    session_jump_end: 'End',
+    session_jump_end_label: 'Jump to end of session',
     queued_label: 'Sends after response',
     queued_count: (n) => n === 1 ? '1 queued' : `${n} queued`,
     queued_cancel: 'Cancel queued message',
@@ -8089,6 +8145,8 @@ const LOCALES = {
     settings_update_check_failed: 'Update check failed',
     settings_label_workspace_panel_open: '기본으로 워크스페이스 패널 열기',
     settings_desc_workspace_panel_open: '활성화하면 새 세션마다 워크스페이스/파일 브라우저 패널이 자동으로 열립니다. 언제든지 수동으로 닫을 수 있습니다.',
+    settings_label_session_jump_buttons: 'Show session jump buttons',
+    settings_desc_session_jump_buttons: 'Show floating Start and End buttons while reading long session histories.',
     open_in_browser: '브라우저에서 열기',
     settings_dropdown_conversation: '대화',
     settings_dropdown_appearance: '외형',
@@ -8832,6 +8890,11 @@ function applyLocaleToDOM() {
     const val = t(key);
     if (val && val !== key) el.placeholder = val;
   });
+  document.querySelectorAll('[data-i18n-aria-label]').forEach(el => {
+    const key = el.getAttribute('data-i18n-aria-label');
+    const val = t(key);
+    if (val && val !== key) el.setAttribute('aria-label', val);
+  });
   if (typeof syncAppTitlebar === 'function') syncAppTitlebar();
 }
 

static/index.html

@@ -297,7 +297,8 @@
   <main class="main">
     <div id="mainChat" class="main-view">
     <div class="messages" id="messages">
-      <button id="scrollToBottomBtn" class="scroll-to-bottom-btn" aria-label="Scroll to bottom" onclick="scrollToBottom()" style="display:none">↓</button>
+      <button id="jumpToSessionStartBtn" class="session-jump-btn session-jump-btn--start" aria-label="Jump to beginning of session" data-i18n-aria-label="session_jump_start_label" data-i18n-title="session_jump_start_label" onclick="jumpToSessionStart()" style="display:none"><span aria-hidden="true">↑</span><span data-i18n="session_jump_start">Start</span></button>
+      <button id="scrollToBottomBtn" class="scroll-to-bottom-btn" style="display:none" onclick="scrollToBottom()" aria-label="Scroll to bottom" data-i18n-aria-label="session_jump_end_label" data-i18n-title="session_jump_end_label"><span aria-hidden="true">↓</span><span class="session-jump-btn__text" data-i18n="session_jump_end">End</span></button>
       <div class="empty-state" id="emptyState">
         <div class="empty-logo"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="80" height="80" aria-label="Hermes caduceus">
           <defs>
@@ -863,6 +864,13 @@
               </label>
               <div style="font-size:11px;color:var(--muted);margin-top:4px" data-i18n="settings_desc_workspace_panel_open">When enabled, the workspace / file browser panel opens automatically with each new session. You can still close it manually at any time.</div>
             </div>
+            <div class="settings-field">
+              <label style="display:flex;align-items:center;gap:8px;cursor:pointer">
+                <input type="checkbox" id="settingsSessionJumpButtons" style="width:15px;height:15px;accent-color:var(--accent)">
+                <span data-i18n="settings_label_session_jump_buttons">Show session jump buttons</span>
+              </label>
+              <div style="font-size:11px;color:var(--muted);margin-top:4px" data-i18n="settings_desc_session_jump_buttons">Show floating Start and End buttons while reading long session histories.</div>
+            </div>
             <div id="settingsAppearanceAutosaveStatus" class="settings-autosave-status" aria-live="polite"></div>
           </div>
           <div class="settings-pane" id="settingsPanePreferences">

static/panels.js

@@ -4251,6 +4251,7 @@ function _appearancePayloadFromUi(){
     theme: ($('settingsTheme')||{}).value || localStorage.getItem('hermes-theme') || 'dark',
     skin: ($('settingsSkin')||{}).value || localStorage.getItem('hermes-skin') || 'default',
     font_size: ($('settingsFontSize')||{}).value || localStorage.getItem('hermes-font-size') || 'default',
+    session_jump_buttons: !!($('settingsSessionJumpButtons')||{}).checked,
   };
 }
 
@@ -4298,6 +4299,10 @@ async function _autosaveAppearanceSettings(payload){
     if(saved&&saved.font_size){
       localStorage.setItem('hermes-font-size',saved.font_size);
     }
+    if(saved){
+      window._sessionJumpButtonsEnabled=!!saved.session_jump_buttons;
+      if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
+    }
     _setAppearanceAutosaveStatus('saved');
   }catch(e){
     console.warn('[settings] appearance autosave failed', e);
@@ -4454,6 +4459,17 @@ async function loadSettingsPanel(){
     const fontSizeSel=$('settingsFontSize');
     if(fontSizeSel) fontSizeSel.value=fontSizeVal;
     if(typeof _syncFontSizePicker==='function') _syncFontSizePicker(fontSizeVal);
+    const jumpButtonsCb=$('settingsSessionJumpButtons');
+    if(jumpButtonsCb){
+      jumpButtonsCb.checked=!!settings.session_jump_buttons;
+      window._sessionJumpButtonsEnabled=jumpButtonsCb.checked;
+      jumpButtonsCb.onchange=function(){
+        window._sessionJumpButtonsEnabled=this.checked;
+        if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
+        _scheduleAppearanceAutosave();
+      };
+    }
+    if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
     // Workspace panel default-open toggle (localStorage-backed)
     // Uses a separate key (hermes-webui-workspace-panel-pref) so that
     // closing the panel via toolbar X does not clear the user's preference.
@@ -5124,6 +5140,8 @@ function _applySavedSettingsUi(saved, body, opts){
   window._notificationsEnabled=body.notifications_enabled;
   window._showThinking=body.show_thinking!==false;
   window._simplifiedToolCalling=body.simplified_tool_calling!==false;
+  window._sessionJumpButtonsEnabled=!!body.session_jump_buttons;
+  if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
   window._sidebarDensity=sidebarDensity==='detailed'?'detailed':'compact';
   window._busyInputMode=body.busy_input_mode||'queue';
   window._botName=body.bot_name||'Hermes';
@@ -5221,6 +5239,7 @@ async function saveSettings(andClose){
   body.theme=theme;
   body.skin=skin;
   body.font_size=fontSize;
+  body.session_jump_buttons=!!($('settingsSessionJumpButtons')||{}).checked;
   body.language=language;
   body.show_token_usage=showTokenUsage;
   body.show_tps=showTps;

static/style.css

@@ -772,9 +772,16 @@
   .workspace-toggle-btn:disabled{opacity:.38;cursor:not-allowed;}
   .chip.model{color:var(--accent-text);border-color:var(--accent-bg-strong);background:var(--accent-bg);}
   .messages{flex:1;overflow-y:auto;display:flex;flex-direction:column;min-height:0;position:relative;z-index:0;-webkit-overflow-scrolling:touch;touch-action:pan-y;overscroll-behavior-y:contain;overflow-anchor:none;}
-  /* sticky-first-child: button is first child of .messages so its natural position is above viewport; sticky+bottom:16px pins it there when visible */
-  .scroll-to-bottom-btn{position:sticky;bottom:16px;align-self:flex-end;margin-right:20px;width:32px;height:32px;border-radius:50%;border:1px solid var(--border2);background:var(--code-bg);color:var(--muted);font-size:16px;cursor:pointer;display:flex;align-items:center;justify-content:center;box-shadow:0 2px 8px rgba(0,0,0,.25);z-index:10;transition:color .12s,border-color .12s,background .12s;}
+  /* sticky-first-child: button is early in .messages so its natural position is above viewport; sticky+bottom pins it there when visible */
+  .scroll-to-bottom-btn{position:sticky;bottom:16px;align-self:flex-end;margin-right:20px;width:32px;height:32px;border-radius:50%;border:1px solid var(--border2);background:var(--code-bg);color:var(--muted);font-size:16px;cursor:pointer;display:flex;align-items:center;justify-content:center;box-shadow:0 2px 8px rgba(0,0,0,.25);z-index:10;transition:color .12s,border-color .12s,background .12s,transform .12s;}
   .scroll-to-bottom-btn:hover{color:var(--text);border-color:var(--border);background:var(--hover-bg);}
+  .session-jump-btn__text{display:none;}
+  .session-jump-btn{position:sticky;align-self:flex-end;flex:0 0 32px;min-height:32px;margin-right:20px;height:32px;border-radius:999px;border:1px solid var(--border2);background:var(--code-bg);color:var(--muted);font-size:12px;font-weight:600;cursor:pointer;display:flex;align-items:center;justify-content:center;gap:5px;padding:0 11px;box-shadow:0 2px 8px rgba(0,0,0,.25);z-index:11;transition:color .12s,border-color .12s,background .12s,opacity .12s,transform .12s;}
+  .session-jump-btn:hover{color:var(--text);border-color:var(--border);background:var(--hover-bg);transform:translateY(-1px);}
+  .session-jump-btn--start{top:16px;margin-bottom:-36px;}
+  .messages.session-nav-enabled .scroll-to-bottom-btn{width:auto;min-width:32px;border-radius:999px;font-size:12px;font-weight:600;gap:5px;padding:0 11px;}
+  .messages.session-nav-enabled .scroll-to-bottom-btn:hover{transform:translateY(-1px);}
+  .messages.session-nav-enabled .session-jump-btn__text{display:inline;}
   .messages-inner{margin:0 auto;width:100%;padding:20px 24px 32px;display:flex;flex-direction:column;}
   @media(min-width:1400px){.messages-inner{max-width:1100px;}}
   @media(min-width:1800px){.messages-inner{max-width:1200px;}}

static/ui.js

@@ -205,6 +205,48 @@ function _showEarlierRenderedMessages(){
   }
   _scrollPinned=false;
 }
+function _isSessionJumpButtonsEnabled(){
+  return window._sessionJumpButtonsEnabled===true;
+}
+function _applySessionNavigationPrefs(){
+  const container=$('messages');
+  if(container) container.classList.toggle('session-nav-enabled',_isSessionJumpButtonsEnabled());
+  _updateSessionStartJumpButton();
+}
+function _updateSessionStartJumpButton(){
+  const btn=$('jumpToSessionStartBtn');
+  const container=$('messages');
+  if(!btn||!container) return;
+  if(!_isSessionJumpButtonsEnabled()){
+    btn.style.display='none';
+    return;
+  }
+  const hasSession=!!(S&&S.session&&S.messages&&S.messages.length);
+  const awayFromStart=container.scrollTop>Math.max(240,container.clientHeight*0.35);
+  const hasScrollableHistory=container.scrollHeight>container.clientHeight+Math.max(240,container.clientHeight*0.35);
+  const canRevealStart=hasScrollableHistory||_messageHiddenBeforeCount()>0||!!(typeof _messagesTruncated!=='undefined'&&_messagesTruncated);
+  btn.style.display=(hasSession&&canRevealStart&&awayFromStart)?'flex':'none';
+}
+async function jumpToSessionStart(){
+  const container=$('messages');
+  if(!container||!S.session) return;
+  _scrollPinned=false;
+  _messageUserUnpinned=true;
+  _programmaticScroll=true;
+  try{
+    if(typeof _ensureAllMessagesLoaded==='function') await _ensureAllMessagesLoaded();
+    _messageRenderWindowSize=Math.max(_currentMessageRenderWindowSize(),_messageRenderableMessageCount());
+    renderMessages({ preserveScroll:true });
+    requestAnimationFrame(()=>{
+      container.scrollTop=0;
+      _updateSessionStartJumpButton();
+      requestAnimationFrame(()=>{ _programmaticScroll=false; });
+    });
+  }catch(e){
+    console.warn('jumpToSessionStart failed:',e);
+    _programmaticScroll=false;
+  }
+}
 
 const DASHBOARD_STATUS_TTL_MS=60000;
 let _dashboardStatusCache=null;
@@ -1574,6 +1616,7 @@ if (typeof window !== 'undefined') window._resetScrollDirectionTracker = _resetS
       } // #1360
       const btn=$('scrollToBottomBtn');
       if(btn) btn.style.display=_scrollPinned?'none':'flex';
+      if(typeof _updateSessionStartJumpButton==='function') _updateSessionStartJumpButton();
       // Load older messages when scrolled near the top
       if(el.scrollTop<80 && typeof _messagesTruncated!=='undefined' && _messagesTruncated && typeof _loadOlderMessages==='function'){
         _loadOlderMessages();
@@ -1913,6 +1956,7 @@ function scrollToBottom(){
   _settleMessageScrollToBottom(true);
   const btn=$('scrollToBottomBtn');
   if(btn) btn.style.display='none';
+  if(typeof _updateSessionStartJumpButton==='function') _updateSessionStartJumpButton();
 }
 
 function _fmtOllamaLabel(mid){
@@ -4566,6 +4610,7 @@ function renderMessages(options){
       inner.innerHTML=cached.html;
       _sessionHtmlCacheSid=sid;
       _wireMessageWindowLoadEarlierButton();
+      if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
       _scrollAfterMessageRender(preserveScroll);
       requestAnimationFrame(()=>{highlightCode();addCopyButtons();loadDiffInline();loadCsvInline();loadExcalidrawInline();loadPdfInline();loadHtmlInline();renderMermaidBlocks();renderKatexBlocks();});
       requestAnimationFrame(()=>{highlightCode();addCopyButtons();initTreeViews();loadPdfInline();loadHtmlInline();renderMermaidBlocks();renderKatexBlocks();});
@@ -4626,6 +4671,7 @@ function renderMessages(options){
   const renderVisWithIdx=visWithIdx.slice(windowStart);
   const firstRenderedRawIdx=renderVisWithIdx.length?renderVisWithIdx[0].rawIdx:Infinity;
   const hasServerOlder=!!(typeof _messagesTruncated!=='undefined' && _messagesTruncated && S.messages.length>0);
+  if(typeof _applySessionNavigationPrefs==='function') _applySessionNavigationPrefs();
   if(hiddenBeforeCount>0 || hasServerOlder){
     const indicator=document.createElement('button');
     indicator.type='button';

tests/test_session_jump_buttons.py

@@ -0,0 +1,77 @@
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parents[1]
+UI_JS = (REPO / "static" / "ui.js").read_text(encoding="utf-8")
+BOOT_JS = (REPO / "static" / "boot.js").read_text(encoding="utf-8")
+INDEX_HTML = (REPO / "static" / "index.html").read_text(encoding="utf-8")
+STYLE_CSS = (REPO / "static" / "style.css").read_text(encoding="utf-8")
+I18N_JS = (REPO / "static" / "i18n.js").read_text(encoding="utf-8")
+PANELS_JS = (REPO / "static" / "panels.js").read_text(encoding="utf-8")
+CONFIG_PY = (REPO / "api" / "config.py").read_text(encoding="utf-8")
+
+
+def _function_body(src: str, signature: str) -> str:
+    start = src.index(signature)
+    brace = src.index("{", start)
+    depth = 0
+    for i in range(brace, len(src)):
+        if src[i] == "{":
+            depth += 1
+        elif src[i] == "}":
+            depth -= 1
+            if depth == 0:
+                return src[start : i + 1]
+    raise AssertionError(f"function body not found: {signature}")
+
+
+def test_session_jump_buttons_are_opt_in_and_keep_existing_bottom_button():
+    assert '"session_jump_buttons": False' in CONFIG_PY
+    assert '"session_jump_buttons"' in CONFIG_PY
+    assert "window._sessionJumpButtonsEnabled=!!s.session_jump_buttons" in BOOT_JS
+    assert "window._sessionJumpButtonsEnabled=false" in BOOT_JS
+    assert "session_jump_buttons: !!($('settingsSessionJumpButtons')||{}).checked" in PANELS_JS
+
+    scroll_listener = UI_JS[UI_JS.index("el.addEventListener('scroll'") : UI_JS.index("})();", UI_JS.index("el.addEventListener('scroll'"))]
+    assert "if(btn) btn.style.display=_scrollPinned?'none':'flex'" in scroll_listener
+    assert "!_isSessionJumpButtonsEnabled()||_scrollPinned" not in UI_JS
+
+
+def test_jump_to_session_start_button_loads_full_history_and_scrolls_top():
+    jump = _function_body(UI_JS, "async function jumpToSessionStart")
+    update = _function_body(UI_JS, "function _updateSessionStartJumpButton")
+
+    assert 'id="jumpToSessionStartBtn"' in INDEX_HTML
+    assert 'class="session-jump-btn session-jump-btn--start"' in INDEX_HTML
+    assert "data-i18n=\"session_jump_start\"" in INDEX_HTML
+    assert "data-i18n=\"session_jump_end\"" in INDEX_HTML
+    assert "data-i18n-aria-label=\"session_jump_start_label\"" in INDEX_HTML
+    assert "data-i18n-aria-label=\"session_jump_end_label\"" in INDEX_HTML
+
+    assert "_ensureAllMessagesLoaded" in jump
+    assert "_messageRenderWindowSize=Math.max(_currentMessageRenderWindowSize(),_messageRenderableMessageCount())" in jump
+    assert "renderMessages({ preserveScroll:true })" in jump
+    assert "container.scrollTop=0" in jump
+    assert "btn.style.display=(hasSession&&canRevealStart&&awayFromStart)?'flex':'none'" in update
+
+
+def test_session_jump_buttons_match_pill_layout_without_regressing_default_arrow():
+    assert ".session-jump-btn" in STYLE_CSS
+    assert ".session-jump-btn--start{top:16px" in STYLE_CSS
+    assert ".session-jump-btn__text{display:none" in STYLE_CSS
+    assert ".messages.session-nav-enabled .scroll-to-bottom-btn" in STYLE_CSS
+    assert ".messages.session-nav-enabled .session-jump-btn__text{display:inline" in STYLE_CSS
+    assert "classList.toggle('session-nav-enabled',_isSessionJumpButtonsEnabled())" in UI_JS
+
+
+def test_session_jump_buttons_are_i18n_localized_in_text_tooltip_and_aria():
+    for key in [
+        "session_jump_start",
+        "session_jump_start_label",
+        "session_jump_end",
+        "session_jump_end_label",
+        "settings_label_session_jump_buttons",
+        "settings_desc_session_jump_buttons",
+    ]:
+        assert I18N_JS.count(f"{key}:") >= 8, f"missing locale entries for {key}"
+    assert "document.querySelectorAll('[data-i18n-aria-label]')" in I18N_JS
+    assert "el.setAttribute('aria-label', val)" in I18N_JS