Avoid startup session download

app.py

@@ -38,12 +38,12 @@ TIMESTAMP_KEYS = (
 )
 
 
-def _hub_token() -> str | bool:
+def _hub_token() -> str | None:
     return (
         os.environ.get("HF_TOKEN")
         or os.environ.get("HUGGING_FACE_HUB_TOKEN")
         or os.environ.get("HUGGINGFACE_HUB_TOKEN")
-        or True
+        or None
     )
 
 
@@ -543,6 +543,32 @@ def _render_error(title: str, details: str) -> tuple[str, str, str, int]:
     )
 
 
+def _initial_view(choices: list[str]) -> tuple[str, str, str, int]:
+    choices_label = f"{len(choices):,} session files available" if choices else "No session files available"
+    summary = (
+        '<section class="summary-panel">'
+        '<div class="summary-topline">'
+        "<div><h1>Select a session</h1>"
+        f"<p>{_escape(choices_label)} from {DATASET_REPO}</p></div>"
+        '<div class="repo-pill">private dataset</div>'
+        "</div>"
+        '<div class="metrics-grid">'
+        f'{_metric("Startup mode", "metadata only")}'
+        f'{_metric("Files listed", _fmt_number(len(choices)))}'
+        f'{_metric("Downloads", "on demand")}'
+        f'{_metric("Page size", _fmt_number(PAGE_SIZE))}'
+        "</div>"
+        "</section>"
+    )
+    transcript = (
+        '<section class="empty-state">'
+        "<h2>No session loaded yet</h2>"
+        "<p>Choose a session in the sidebar and select Load session. Files are downloaded lazily.</p>"
+        "</section>"
+    )
+    return summary, transcript, "No session file downloaded yet.", 1
+
+
 def render_session(session_name: str | None, query: str | None = "", page: int | float | None = 1) -> tuple[str, str, str, int]:
     choices, list_error = _list_sessions_cached()
     if not choices:
@@ -601,8 +627,8 @@ def previous_page(session_name: str | None, query: str | None, page: int | float
 def refresh_sessions() -> tuple[Any, str, str, str, int, str]:
     _list_sessions_cached.cache_clear()
     choices = _session_choices()
-    value = choices[0] if choices else None
-    summary, transcript, page_info, page = render_session(value, "", 1)
+    value = None
+    summary, transcript, page_info, page = _initial_view(choices)
     return gr.update(choices=choices, value=value), summary, transcript, page_info, page, ""
 
 
@@ -1103,8 +1129,8 @@ html, body, .gradio-container {
 
 def build_app() -> gr.Blocks:
     choices = _session_choices()
-    default = choices[0] if choices else None
-    initial_summary, initial_transcript, initial_page_info, initial_page = render_session(default, "", 1)
+    default = None
+    initial_summary, initial_transcript, initial_page_info, initial_page = _initial_view(choices)
 
     with gr.Blocks(title=APP_TITLE, fill_width=True) as demo:
         with gr.Row(elem_id="ct-app", elem_classes=["ct-shell"]):
@@ -1129,6 +1155,7 @@ def build_app() -> gr.Blocks:
                     max_lines=1,
                 )
                 filter_button = gr.Button("Filter", variant="primary")
+                load_button = gr.Button("Load session")
                 refresh_button = gr.Button("Refresh file list")
                 page_state = gr.State(initial_page)
                 page_info = gr.Markdown(initial_page_info, elem_classes=["ct-page-info"])
@@ -1147,6 +1174,13 @@ def build_app() -> gr.Blocks:
             api_name="load_session",
             show_progress="minimal",
         )
+        load_button.click(
+            fn=load_session,
+            inputs=session,
+            outputs=[summary, transcript, page_info, page_state, search],
+            api_name=False,
+            show_progress="minimal",
+        )
         filter_button.click(
             fn=filter_session,
             inputs=[session, search],