Restore the activity bar above the session details

src/toad/toad.tcss

@@ -24,6 +24,11 @@ LoadingIndicator {
     background: transparent;
 }
 
+Throbber {
+    width: 100%;
+    height: 1;
+}
+
 .-hidden {
     display: none;
 }

src/toad/widgets/comms_chat.py

@@ -95,6 +95,7 @@ def compose(self) -> ComposeResult:
         yield Flash()
         with containers.Vertical(id="prompt-stack"):
             yield from self.conversation.compose_activity(self)
+            yield self.throbber_above
             yield self.conversation.prompt().data_bind(
                 project_path=Conversation.project_path,
                 working_directory=Conversation.working_directory,
@@ -227,6 +228,9 @@ async def _refresh(self) -> Worker | None:
             return
         return history.page_source.schedule_refresh(self)
 
+    def history_loading(self) -> bool:
+        return self.message_history.reading
+
     async def _refresh_source(self) -> None:
         """Read what changed in the conversation and draw it: the history's source work."""
         from agent_comms.coordination_errors import CoordinationReadUnavailable, StaleRevision

src/toad/widgets/conversation.py

@@ -112,6 +112,7 @@
 from toad.widgets.splash_text import ThreadLoading
 from toad.widgets.terminal import Terminal
 from toad.widgets.terminal_tool import TerminalTool
+from toad.widgets.throbber import AboveThrobber
 from toad.widgets.transcript_history import JumpToLatest, TranscriptHistory
 from toad.widgets.user_input import UserInput
 
@@ -541,6 +542,7 @@ def __init__(
         self.turns = ConversationTurn(
             self._turn_changed, lambda: self.agent_binding.presentation.turns
         )
+        self.throbber_above = AboveThrobber(self.working)
         self._initialize_session(
             project_path,
             agent,
@@ -904,7 +906,18 @@ async def sync_project_path(self, path: Path) -> None:
                     await self._shell.change_directory(str(path))
         await self.agent_binding.project_changed(path)
 
+    def history_loading(self) -> bool:
+        """Whether this view's history is reading its first page; only wire histories page in."""
+        return False
+
+    def working(self) -> bool:
+        return self.turns.owner.busy or self._observed_working or self.history_loading()
+
+    def sync_working(self) -> None:
+        self.throbber_above.sync()
+
     def _turn_changed(self, owner: TurnOwner) -> None:
+        self.sync_working()
         if (prompt := self.query_one_optional(Prompt)) is not None:
             prompt.sync_turn()
         if (details := self.query_one_optional(SessionDetails)) is not None:
@@ -914,6 +927,7 @@ def _turn_changed(self, owner: TurnOwner) -> None:
     @on(ObservedThreadActivity.Changed)
     def _observed_activity_changed(self, event: ObservedThreadActivity.Changed) -> None:
         event.stop()
+        self.sync_working()
         if (prompt := self.query_one_optional(Prompt)) is not None:
             prompt.sync_session()
 
@@ -957,6 +971,7 @@ def compose(self) -> ComposeResult:
                 ),
             )
             self.refresh_thread_status()
+            yield self.throbber_above
             yield self.thread_activity
             prompt = self.operational_sources.prompt(self).data_bind(
                 project_path=Conversation.project_path,

src/toad/widgets/throbber.py

@@ -0,0 +1,94 @@
+from collections.abc import Callable
+from functools import cached_property
+from typing import ClassVar
+
+from rich.segment import Segment
+
+from textual.visual import Visual
+
+from textual.style import Style
+from textual.strip import Strip
+from textual.visual import RenderOptions
+from textual.reactive import reactive
+from textual.css.styles import RulesMap
+
+from ui_theme.effects import ACTIVITY_SWEEP, Ribbon
+from ui_theme.scheme import TurnBandColour
+
+from toad.frame_presentation import Animated
+from toad.textual_colours import BlockInk, BottomInk
+
+
+class ThrobberVisual(Visual):
+    """The activity sweep: a band of theme colours moving across one row.
+
+    `ui_theme.effects.ACTIVITY_SWEEP` says which colours and how fast; the
+    app's colours backend paints the frame the animation shows now.
+    """
+
+    def __init__(self, throbber: Throbber) -> None:
+        self.throbber = throbber
+
+    def render_strips(
+        self, width: int, height: int | None, style: Style, options: RenderOptions
+    ) -> list[Strip]:
+        throbber = self.throbber
+        base = Strip([Segment("█" * width, style.rich_style)], cell_length=width)
+        frame = throbber.effect_frame(throbber.effect)
+        return [throbber.app.colours.paint_gradient(frame, base, edge=throbber.ink_edge)]
+
+    def get_optimal_width(self, rules: RulesMap, container_width: int) -> int:
+        return container_width
+
+    def get_height(self, rules: RulesMap, width: int) -> int:
+        return 1
+
+
+class Throbber(Animated[Ribbon]):
+    _paint_only_render = True
+    tone = TurnBandColour
+    # The row is always reserved; only its paint and animation change.
+    busy = reactive(False, layout=False)
+    effect = ACTIVITY_SWEEP
+    ink_edge: ClassVar[type[BlockInk]]
+
+    @cached_property
+    def _busy_visual(self) -> ThrobberVisual:
+        # Glyph geometry belongs here; frame, colours and cadence stay in the
+        # shared effect. A changing band never changes the reserved row.
+        return ThrobberVisual(self)
+
+    def on_mount(self) -> None:
+        self.watch_busy(self.busy)
+
+    def watch_busy(self, busy: bool) -> None:
+        # The activity owner's sync changes animation ownership and retires its paint.
+        if busy and self.is_mounted:
+            if self.effect not in self.effects:
+                self.run_effect(self.effect)
+        else:
+            self.stop_effect(self.effect)
+        self.refresh()
+
+    def render(self) -> ThrobberVisual | str:
+        return self._busy_visual if self.busy else ""
+
+
+class ObservedThrobber(Throbber):
+    """Paint an existing activity owner without a writable busy mirror."""
+
+    def __init__(self, read_busy: Callable[[], bool], **kwargs) -> None:
+        super().__init__(**kwargs)
+        self._read_busy = read_busy
+
+    def compute_busy(self) -> bool:
+        return self._read_busy()
+
+    def sync(self) -> None:
+        self.watch_busy(self.busy)
+
+
+class AboveThrobber(ObservedThrobber):
+    """The upper bar hugs the status from its cell's bottom edge."""
+
+    ink_edge = BottomInk

src/toad/widgets/wire_history.py

@@ -1,9 +1,11 @@
 """A channel or direct conversation drawn by the line history, with its read marks."""
 
 from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
+from textual.reactive import var
+
 from agent_comms.coordination_errors import StaleRevision
 from agent_comms.historical_views import ConversationObservation
 
@@ -32,6 +34,8 @@
     """
 
     page_source: WirePageBuffer | ClosedHistory
+    # Reading the bound source's first page: the view's activity bar shows it.
+    reading = var(False)
 
     def __init__(self, prepared: PreparedTranscriptPage, page_source: WirePageBuffer | ClosedHistory,
                  *, view: ViewT, notification_view, **kwargs) -> None:
@@ -82,10 +86,17 @@
     async def read_changes(self) -> bool:
         """Draw what changed in the source; False when the stores are as last drawn."""
         source = self.page_source
-        observed = await source.observe_changes(source.revision)
-        if source is not self.page_source:
-            return False
-        return await observed.apply(self, source)
+        self.reading = self.undrawn
+        try:
+            observed = await source.observe_changes(source.revision)
+            if source is not self.page_source:
+                return False
+            return await observed.apply(self, source)
+        finally:
+            self.reading = False
+
+    def watch_reading(self, _reading: bool) -> None:
+        self.view.sync_working()
 
     # What is drawn