feat(tui): implement actor thought block rendering

Add ActorThought block widget with collapsed max-10-line rendering, expand behavior, and app-level visibility toggle binding. Extend Behave/Robot coverage and styling for the new block while wiring it into TUI composition and input flow.

ISSUES CLOSED: #1001

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Added TUI ActorThought block rendering with muted styling, collapsed-by-default
+  max-10-line view, and keyboard expansion support. Wired the block into the
+  Textual app layout and added `ctrl+shift+t` visibility toggle, plus Behave
+  and Robot coverage for truncation/expansion behavior. (#1001)
 - Strengthened WF02 trusted-profile integration coverage for automated test
   generation. The helper now validates and incorporates mocked provider output
   (instead of discarding it), asserts all WF02 invariant conventions (test-only

features/steps/tui_app_coverage_steps.py

@@ -10,6 +10,8 @@ These steps target uncovered lines in cleveragents/tui/app.py:
 - Lines 131-142: _refresh_persona_bar method
 - Lines 144-185: on_input_submitted (all branches)
 - Line 189: CleverAgentsTuiApp alias
+
+Also covers ActorThought block behavior from issue #1001.
 """
 
 import importlib
@@ -481,3 +483,49 @@ def step_alias_check(context):
     assert (
         context._tui_app_mod.CleverAgentsTuiApp.__name__ == "_TextualCleverAgentsTuiApp"
     )
+
+
+# ---------------------------------------------------------------------------
+# ActorThought block (issue #1001)
+# ---------------------------------------------------------------------------
+@given("an ActorThought block widget")
+def step_actor_thought_widget(context):
+    from cleveragents.tui.widgets.actor_thought_block import ActorThoughtBlock
+
+    context._actor_thought_block = ActorThoughtBlock()
+
+
+@when("I set a 14-line thought on the ActorThought block")
+def step_set_actor_thought(context):
+    thought = "\n".join(f"line {index}" for index in range(1, 15))
+    context._actor_thought_block.set_thought(thought)
+
+
+@when("I toggle ActorThought expansion")
+def step_toggle_actor_thought(context):
+    context._actor_thought_block.toggle_expanded()
+
+
+@then('the ActorThought block should contain "{text}"')
+def step_actor_thought_contains(context, text):
+    rendered = context._actor_thought_block.rendered_text()
+    assert text in rendered, f"Expected '{text}' in '{rendered}'"
+
+
+@then('the ActorThought block should not contain "{text}"')
+def step_actor_thought_not_contains(context, text):
+    rendered = context._actor_thought_block.rendered_text()
+    assert text not in rendered, f"Did not expect '{text}' in '{rendered}'"
+
+
+@then("compose should include an ActorThought block widget")
+def step_compose_has_actor_thought_widget(context):
+    assert any(
+        item.__class__.__name__ == "ActorThoughtBlock"
+        for item in context._tui_compose_items
+    )
+
+
+@then('the app class should include key binding "{key}"')
+def step_binding_exists(context, key):
+    assert any(binding[0] == key for binding in context._tui_app.BINDINGS)

features/tui_app_coverage.feature

@@ -47,7 +47,7 @@ Feature: TUI App Coverage
     Given a mock command router and persona state
     When I instantiate the Textual TUI app
     Then the app class should have CSS_PATH set to "cleveragents.tcss"
-    And the app class should have 3 key bindings
+    And the app class should have 4 key bindings
 
   # --- compose method (lines 102-112) ---
 
@@ -170,3 +170,25 @@ Feature: TUI App Coverage
     And I call on_mount on the app
     And I submit "!true" to the app
     Then the conversation widget should contain "(empty output)"
+
+  # --- ActorThought block rendering (issue #1001) ---
+
+  Scenario: ActorThought block collapses to max 10 lines
+    Given an ActorThought block widget
+    When I set a 14-line thought on the ActorThought block
+    Then the ActorThought block should contain "line 10"
+    And the ActorThought block should not contain "line 11"
+    And the ActorThought block should contain "4 more lines - space to expand"
+
+  Scenario: ActorThought block expands to full content
+    Given an ActorThought block widget
+    When I set a 14-line thought on the ActorThought block
+    And I toggle ActorThought expansion
+    Then the ActorThought block should contain "line 14"
+
+  Scenario: Textual TUI app includes ActorThought widget and toggle binding
+    Given a mock command router and persona state
+    When I instantiate the Textual TUI app
+    And I call compose on the app
+    Then compose should include an ActorThought block widget
+    And the app class should include key binding "ctrl+shift+t"

robot/tui_smoke.robot

@@ -40,3 +40,21 @@ TUI Headless Includes Router Help Payload
     Should Be Equal As Integers    ${result.rc}    0
     Should Contain    ${result.stdout}    "help"
     Should Contain    ${result.stdout}    /persona
+
+TUI ActorThought Block Truncates And Expands
+    ${script}=    Catenate    SEPARATOR=\n
+    ...    from cleveragents.tui.widgets.actor_thought_block import ActorThoughtBlock
+    ...    block = ActorThoughtBlock()
+    ...    text = "\\n".join(f"line {index}" for index in range(1, 15))
+    ...    block.set_thought(text)
+    ...    collapsed = block.rendered_text()
+    ...    assert "line 10" in collapsed
+    ...    assert "line 11" not in collapsed
+    ...    assert "4 more lines - space to expand" in collapsed
+    ...    block.toggle_expanded()
+    ...    expanded = block.rendered_text()
+    ...    assert "line 14" in expanded
+    ...    print("actor-thought-block-ok")
+    ${result}=    Run Process    ${PYTHON}    -c    ${script}    shell=False    stderr=STDOUT
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    actor-thought-block-ok

src/cleveragents/tui/app.py

@@ -10,6 +10,7 @@ from typing import TYPE_CHECKING, Any, ClassVar, Protocol
 from cleveragents.tui.input.modes import InputMode, InputModeRouter
 from cleveragents.tui.input.reference_parser import suggestions
 from cleveragents.tui.persona.state import PersonaState
+from cleveragents.tui.widgets.actor_thought_block import ActorThoughtBlock
 from cleveragents.tui.widgets.persona_bar import PersonaBar
 from cleveragents.tui.widgets.prompt import PromptInput
 from cleveragents.tui.widgets.reference_picker import ReferencePickerOverlay
@@ -86,6 +87,7 @@ if _TEXTUAL_AVAILABLE:
             ("ctrl+q", "quit", "Quit"),
             ("f1", "help", "Help"),
             ("ctrl+t", "cycle_preset", "Cycle Preset"),
+            ("ctrl+shift+t", "toggle_thoughts", "Toggle Thoughts"),
         ]
 
         def __init__(
@@ -98,11 +100,13 @@ if _TEXTUAL_AVAILABLE:
             self._command_router = command_router
             self._persona_state = persona_state
             self._session = SessionView(session_id="default", transcript=[])
+            self._thoughts_visible = True
 
         def compose(self) -> Any:
             yield _Header(show_clock=True)
             with _Vertical(id="main-column"):
                 yield _Static("CleverAgents TUI", id="conversation")
+                yield ActorThoughtBlock(id="actor-thought")
                 yield ReferencePickerOverlay(id="reference-picker")
                 yield SlashCommandOverlay(id="slash-overlay")
                 yield PromptInput(
@@ -119,6 +123,8 @@ if _TEXTUAL_AVAILABLE:
             slash.set_commands(
                 "", ["persona list", "persona set", "session show", "help"]
             )
+            thought_block = self.query_one("#actor-thought", ActorThoughtBlock)
+            thought_block.set_visible(self._thoughts_visible)
 
         def action_help(self) -> None:
             conversation = self.query_one("#conversation", _Static)
@@ -128,6 +134,11 @@ if _TEXTUAL_AVAILABLE:
             self._persona_state.cycle_preset(self._session.session_id)
             self._refresh_persona_bar()
 
+        def action_toggle_thoughts(self) -> None:
+            self._thoughts_visible = not self._thoughts_visible
+            thought_block = self.query_one("#actor-thought", ActorThoughtBlock)
+            thought_block.set_visible(self._thoughts_visible)
+
         def _refresh_persona_bar(self) -> None:
             persona = self._persona_state.active_persona(self._session.session_id)
             preset = self._persona_state.current_preset(self._session.session_id)
@@ -182,6 +193,8 @@ if _TEXTUAL_AVAILABLE:
                 ref_picker.set_suggestions(
                     text, suggestions(text.replace("@", "").strip())
                 )
+            thought_block = self.query_one("#actor-thought", ActorThoughtBlock)
+            thought_block.set_thought(f"I am reasoning about: {preview}")
             conversation.update(preview)
 
     _ResolvedTuiApp = _TextualCleverAgentsTuiApp

src/cleveragents/tui/cleveragents.tcss

@@ -14,6 +14,17 @@ Screen {
   background: $panel;
 }
 
+#actor-thought {
+  height: auto;
+  max-height: 10;
+  padding: 0 1;
+  margin: 1 0 0 0;
+  border: round $primary;
+  background: $primary 20%;
+  color: $text-muted;
+  text-style: italic;
+}
+
 #reference-picker {
   height: auto;
   max-height: 8;

src/cleveragents/tui/widgets/__init__.py

@@ -1,11 +1,13 @@
 """Widget collection for CleverAgents TUI."""
 
+from cleveragents.tui.widgets.actor_thought_block import ActorThoughtBlock
 from cleveragents.tui.widgets.persona_bar import PersonaBar
 from cleveragents.tui.widgets.prompt import PromptInput, PromptSubmitted
 from cleveragents.tui.widgets.reference_picker import ReferencePickerOverlay
 from cleveragents.tui.widgets.slash_command_overlay import SlashCommandOverlay
 
 __all__ = [
+    "ActorThoughtBlock",
     "PersonaBar",
     "PromptInput",
     "PromptSubmitted",

src/cleveragents/tui/widgets/actor_thought_block.py

@@ -0,0 +1,72 @@
+"""Actor thought block widget for the conversation stream."""
+
+from __future__ import annotations
+
+import importlib
+from typing import Any
+
+
+def _load_static_base() -> type[Any]:
+    try:
+        return importlib.import_module("textual.widgets").Static
+    except Exception:  # pragma: no cover - optional dependency
+
+        class _FallbackStatic:
+            def __init__(self, *args: object, **kwargs: object) -> None:
+                self._text = ""
+
+            def update(self, text: str) -> None:
+                self._text = text
+
+        return _FallbackStatic
+
+
+_StaticBase = _load_static_base()
+
+
+class ActorThoughtBlock(_StaticBase):
+    """Render actor reasoning in a muted, expandable block."""
+
+    def __init__(self, *args: object, max_lines: int = 10, **kwargs: object) -> None:
+        super().__init__(*args, **kwargs)
+        self._max_lines = max_lines
+        self._expanded = False
+        self._visible = True
+        self._full_text = ""
+        self._text = ""
+
+    def set_thought(self, thought_text: str) -> None:
+        """Set thought text and render in current visibility/expansion mode."""
+        self._full_text = thought_text
+        self._render()
+
+    def set_visible(self, visible: bool) -> None:
+        """Toggle thought block visibility."""
+        self._visible = visible
+        self._render()
+
+    def toggle_expanded(self) -> None:
+        """Toggle between collapsed (max lines) and expanded rendering."""
+        self._expanded = not self._expanded
+        self._render()
+
+    def rendered_text(self) -> str:
+        """Return the latest rendered text payload."""
+        return self._text
+
+    def _render(self) -> None:
+        if not self._visible or not self._full_text.strip():
+            self._text = ""
+            self.update("")
+            return
+
+        all_lines = self._full_text.splitlines() or [self._full_text]
+        rendered_lines = all_lines
+        if not self._expanded and len(all_lines) > self._max_lines:
+            hidden_count = len(all_lines) - self._max_lines
+            rendered_lines = all_lines[: self._max_lines]
+            rendered_lines.append(f"({hidden_count} more lines - space to expand)")
+
+        body = "\n".join(rendered_lines)
+        self._text = f"[i][dim]{body}[/dim][/i]"
+        self.update(self._text)