feat: Add mouse text selection auto-copy to clipboard in TUI

Enable native text selection across tool components and agent messages
with automatic clipboard copy, toast notification, and decorative icon
stripping. Replace Padding wrappers with Text to support selection
across multiple renderables.

strix/interface/tui.py

@@ -38,6 +38,9 @@ from strix.llm.config import LLMConfig
 from strix.telemetry.tracer import Tracer, set_global_tracer
 
 
+logger = logging.getLogger(__name__)
+
+
 def get_package_version() -> str:
     try:
         return pkg_version("strix-agent")
@@ -91,6 +94,7 @@ class ChatTextArea(TextArea):  # type: ignore[misc]
 
 
 class SplashScreen(Static):  # type: ignore[misc]
+    ALLOW_SELECT = False
     PRIMARY_GREEN = "#22c55e"
     BANNER = (
         " ███████╗████████╗██████╗ ██╗██╗  ██╗\n"
@@ -667,6 +671,7 @@ class QuitScreen(ModalScreen):  # type: ignore[misc]
 
 class StrixTUIApp(App):  # type: ignore[misc]
     CSS_PATH = "assets/tui_styles.tcss"
+    ALLOW_SELECT = True
 
     SIDEBAR_MIN_WIDTH = 140
 
@@ -783,13 +788,16 @@ class StrixTUIApp(App):  # type: ignore[misc]
             chat_history.can_focus = True
 
             status_text = Static("", id="status_text")
+            status_text.ALLOW_SELECT = False
             keymap_indicator = Static("", id="keymap_indicator")
+            keymap_indicator.ALLOW_SELECT = False
 
             agent_status_display = Horizontal(
                 status_text, keymap_indicator, id="agent_status_display", classes="hidden"
             )
 
             chat_prompt = Static("> ", id="chat_prompt")
+            chat_prompt.ALLOW_SELECT = False
             chat_input = ChatTextArea(
                 "",
                 id="chat_input",
@@ -807,6 +815,7 @@ class StrixTUIApp(App):  # type: ignore[misc]
             agents_tree.guide_style = "dashed"
 
             stats_display = Static("", id="stats_display")
+            stats_display.ALLOW_SELECT = False
 
             vulnerabilities_panel = VulnerabilitiesPanel(id="vulnerabilities_panel")
 
@@ -1005,6 +1014,33 @@ class StrixTUIApp(App):  # type: ignore[misc]
         text.append(message)
         return text, f"chat-placeholder {placeholder_class}"
 
+    @staticmethod
+    def _merge_renderables(renderables: list[Any]) -> Text:
+        """Merge renderables into a single Text for mouse text selection support."""
+        combined = Text()
+        for i, item in enumerate(renderables):
+            if i > 0:
+                combined.append("\n")
+            StrixTUIApp._append_renderable(combined, item)
+        return combined
+
+    @staticmethod
+    def _append_renderable(combined: Text, item: Any) -> None:
+        """Recursively append a renderable's text content to a combined Text."""
+        if isinstance(item, Text):
+            combined.append_text(item)
+        elif isinstance(item, Group):
+            for j, sub in enumerate(item.renderables):
+                if j > 0:
+                    combined.append("\n")
+                StrixTUIApp._append_renderable(combined, sub)
+        else:
+            inner = getattr(item, "renderable", None)
+            if inner is not None:
+                StrixTUIApp._append_renderable(combined, inner)
+            else:
+                combined.append(str(item))
+
     def _get_rendered_events_content(self, events: list[dict[str, Any]]) -> Any:
         renderables: list[Any] = []
 
@@ -1036,10 +1072,10 @@ class StrixTUIApp(App):  # type: ignore[misc]
         if not renderables:
             return Text()
 
-        if len(renderables) == 1:
+        if len(renderables) == 1 and isinstance(renderables[0], Text):
             return renderables[0]
 
-        return Group(*renderables)
+        return self._merge_renderables(renderables)
 
     def _render_streaming_content(self, content: str, agent_id: str | None = None) -> Any:
         cache_key = agent_id or self.selected_agent_id or ""
@@ -1072,10 +1108,10 @@ class StrixTUIApp(App):  # type: ignore[misc]
 
         if not renderables:
             result = Text()
-        elif len(renderables) == 1:
+        elif len(renderables) == 1 and isinstance(renderables[0], Text):
             result = renderables[0]
         else:
-            result = Group(*renderables)
+            result = self._merge_renderables(renderables)
 
         self._streaming_render_cache[cache_key] = (content_len, result)
         return result
@@ -1622,7 +1658,7 @@ class StrixTUIApp(App):  # type: ignore[misc]
             interrupted_text.append("\n")
             interrupted_text.append("⚠ ", style="yellow")
             interrupted_text.append("Interrupted by user", style="yellow dim")
-            return Group(streaming_result, interrupted_text)
+            return self._merge_renderables([streaming_result, interrupted_text])
 
         return AgentMessageRenderer.render_simple(content)
 
@@ -1931,6 +1967,92 @@ class StrixTUIApp(App):  # type: ignore[misc]
             sidebar.remove_class("-hidden")
             chat_area.remove_class("-full-width")
 
+    def on_mouse_up(self, _event: events.MouseUp) -> None:
+        self.set_timer(0.05, self._auto_copy_selection)
+
+    _ICON_PREFIXES: ClassVar[tuple[str, ...]] = (
+        "🐞 ",
+        "🌐 ",
+        "📋 ",
+        "🧠 ",
+        "◆ ",
+        "◇ ",
+        "◈ ",
+        "→ ",
+        "○ ",
+        "● ",
+        "✓ ",
+        "✗ ",
+        "⚠ ",
+        "▍ ",
+        "▍",
+        "┃ ",
+        "• ",
+        ">_ ",
+        "</> ",
+        "<~> ",
+        "[ ] ",
+        "[~] ",
+        "[•] ",
+    )
+
+    _DECORATIVE_LINES: ClassVar[frozenset[str]] = frozenset(
+        {
+            "● In progress...",
+            "✓ Done",
+            "✗ Failed",
+            "✗ Error",
+            "○ Unknown",
+        }
+    )
+
+    @staticmethod
+    def _clean_copied_text(text: str) -> str:
+        lines = text.split("\n")
+        cleaned: list[str] = []
+        for line in lines:
+            stripped = line.lstrip()
+            if stripped in StrixTUIApp._DECORATIVE_LINES:
+                continue
+            if stripped and all(c == "─" for c in stripped):
+                continue
+            out = line
+            for prefix in StrixTUIApp._ICON_PREFIXES:
+                if stripped.startswith(prefix):
+                    leading = line[: len(line) - len(line.lstrip())]
+                    out = leading + stripped[len(prefix) :]
+                    break
+            cleaned.append(out)
+        return "\n".join(cleaned)
+
+    def _auto_copy_selection(self) -> None:
+        copied = False
+
+        try:
+            if self.screen.selections:
+                selected = self.screen.get_selected_text()
+                self.screen.clear_selection()
+                if selected:
+                    cleaned = self._clean_copied_text(selected)
+                    self.copy_to_clipboard(cleaned if cleaned.strip() else selected)
+                    copied = True
+        except Exception:  # noqa: BLE001
+            logger.debug("Failed to copy screen selection", exc_info=True)
+
+        if not copied:
+            try:
+                chat_input = self.query_one("#chat_input", ChatTextArea)
+                selected = chat_input.selected_text
+                if selected and selected.strip():
+                    self.copy_to_clipboard(selected)
+                    chat_input.move_cursor(chat_input.cursor_location)
+                    copied = True
+            except Exception:  # noqa: BLE001
+                logger.debug("Failed to copy chat input selection", exc_info=True)
+
+        if copied:
+            self.notify("Copied to clipboard", timeout=2)
+
 
 async def run_tui(args: argparse.Namespace) -> None:
     """Run strix in interactive TUI mode with textual."""