diff --git a/EvoScientist/cli/widgets/thinking_widget.py b/EvoScientist/cli/widgets/thinking_widget.py
index a76eb36..97d84eb 100644
--- a/EvoScientist/cli/widgets/thinking_widget.py
+++ b/EvoScientist/cli/widgets/thinking_widget.py
@@ -2,6 +2,7 @@
 
 Renders a Rich Panel matching the Rich CLI's style:
 blue border, "Thinking" title with spinner, dim content.
+Collapses to a one-line summary after finalize; click to expand/collapse.
 """
 
 from __future__ import annotations
@@ -9,23 +10,27 @@ from __future__ import annotations
 from rich.panel import Panel
 from rich.text import Text
 
+from textual.events import Click
 from textual.widgets import Static
 
 _SPINNER_FRAMES = "\u280b\u2819\u2839\u2838\u283c\u2834\u2826\u2827\u2807\u280f"
 _MAX_DISPLAY_CHARS = 1000
+_MAX_EXPANDED_CHARS = 5000
 
 
 class ThinkingWidget(Static):
     """Collapsible panel showing the model's extended thinking.
 
     Uses Rich ``Panel`` for rendering, matching the Rich CLI output exactly.
+    While streaming, shows tail-truncated content with spinner.
+    After finalize, collapses to a one-line summary; click to expand/collapse.
 
     Usage::
 
         w = ThinkingWidget(show_thinking=True)
         await container.mount(w)
         w.append_text("reasoning chunk...")
-        w.finalize()  # stop spinner
+        w.finalize()  # stop spinner, collapse
     """
 
     DEFAULT_CSS = """
@@ -40,6 +45,7 @@ class ThinkingWidget(Static):
         self._content = ""
         self._is_active = True
         self._show = show_thinking
+        self._collapsed = False
         self._frame = 0
         self._timer_handle = None
         if not show_thinking:
@@ -54,18 +60,39 @@ class ThinkingWidget(Static):
             self._frame = (self._frame + 1) % len(_SPINNER_FRAMES)
             self._refresh_display()
 
+    def _char_count_label(self) -> str:
+        n = len(self._content)
+        if n >= 1000:
+            return f"{n / 1000:.1f}k chars"
+        return f"{n:,} chars"
+
     def _refresh_display(self) -> None:
         if self._is_active:
+            # Streaming: show tail-truncated content with spinner
             char = _SPINNER_FRAMES[self._frame]
             title = f"Thinking {char}"
+            display = self._content.rstrip()
+            if len(display) > _MAX_DISPLAY_CHARS:
+                display = "..." + display[-_MAX_DISPLAY_CHARS:]
+            body = Text(display, style="dim") if display else Text("...", style="dim")
+        elif self._collapsed:
+            # Finalized + collapsed: first line preview + click hint
+            title = f"Thinking ({self._char_count_label()})"
+            first_line = self._content.strip().split("\n")[0].strip()
+            if len(first_line) > 80:
+                first_line = first_line[:77] + "\u2026"
+            preview = Text(first_line, style="dim")
+            preview.append("  [click to expand]", style="dim italic")
+            body = preview
         else:
-            title = "Thinking"
+            # Finalized + expanded: show with middle elision
+            title = f"Thinking ({self._char_count_label()})"
+            display = self._content.rstrip()
+            if len(display) > _MAX_EXPANDED_CHARS:
+                half = _MAX_EXPANDED_CHARS // 2
+                display = display[:half] + "\n\n... (truncated) ...\n\n" + display[-half:]
+            body = Text(display, style="dim") if display else Text("(empty)", style="dim")
 
-        display = self._content.rstrip()
-        if len(display) > _MAX_DISPLAY_CHARS:
-            display = "..." + display[-_MAX_DISPLAY_CHARS:]
-
-        body = Text(display, style="dim") if display else Text("...", style="dim")
         self.update(Panel(body, title=title, border_style="blue", padding=(0, 1)))
 
     def append_text(self, chunk: str) -> None:
@@ -74,9 +101,17 @@ class ThinkingWidget(Static):
         self._refresh_display()
 
     def finalize(self) -> None:
-        """Mark thinking as complete — stop spinner, dim border."""
+        """Mark thinking as complete — stop spinner, collapse."""
         self._is_active = False
+        self._collapsed = True
         if self._timer_handle is not None:
             self._timer_handle.stop()
             self._timer_handle = None
         self._refresh_display()
+
+    def on_click(self, event: Click) -> None:
+        """Toggle collapsed/expanded state after finalize."""
+        if self._is_active:
+            return
+        self._collapsed = not self._collapsed
+        self._refresh_display()
diff --git a/EvoScientist/stream/display.py b/EvoScientist/stream/display.py
index 95412d6..135223b 100644
--- a/EvoScientist/stream/display.py
+++ b/EvoScientist/stream/display.py
@@ -804,7 +804,7 @@ def _run_streaming(
             async def _periodic_refresh() -> None:
                 try:
                     while True:
-                        await asyncio.sleep(0.1)
+                        await asyncio.sleep(0.05)
                         live.refresh()
                 except asyncio.CancelledError:
                     pass