diff --git a/tests/test_tui_gateway_server.py b/tests/test_tui_gateway_server.py
index dacc55df5..2e385eec9 100644
--- a/tests/test_tui_gateway_server.py
+++ b/tests/test_tui_gateway_server.py
@@ -1066,6 +1066,18 @@ def test_config_set_reasoning_updates_live_session_and_agent(tmp_path, monkeypat
     )
     assert resp_show["result"]["value"] == "show"
     assert server._sessions["sid"]["show_reasoning"] is True
+    assert server._load_cfg()["display"]["sections"]["thinking"] == "expanded"
+
+    resp_hide = server.handle_request(
+        {
+            "id": "3",
+            "method": "config.set",
+            "params": {"session_id": "sid", "key": "reasoning", "value": "hide"},
+        }
+    )
+    assert resp_hide["result"]["value"] == "hide"
+    assert server._sessions["sid"]["show_reasoning"] is False
+    assert server._load_cfg()["display"]["sections"]["thinking"] == "hidden"
 
 
 def test_config_set_verbose_updates_session_mode_and_agent(tmp_path, monkeypatch):
diff --git a/tui_gateway/server.py b/tui_gateway/server.py
index fee8e9550..24f6baf71 100644
--- a/tui_gateway/server.py
+++ b/tui_gateway/server.py
@@ -3105,12 +3105,34 @@ def _(rid, params: dict) -> dict:
 
             arg = str(value or "").strip().lower()
             if arg in ("show", "on"):
-                _write_config_key("display.show_reasoning", True)
+                cfg = _load_cfg()
+                display = cfg.get("display") if isinstance(cfg.get("display"), dict) else {}
+                sections = (
+                    display.get("sections")
+                    if isinstance(display.get("sections"), dict)
+                    else {}
+                )
+                display["show_reasoning"] = True
+                sections["thinking"] = "expanded"
+                display["sections"] = sections
+                cfg["display"] = display
+                _save_cfg(cfg)
                 if session:
                     session["show_reasoning"] = True
                 return _ok(rid, {"key": key, "value": "show"})
             if arg in ("hide", "off"):
-                _write_config_key("display.show_reasoning", False)
+                cfg = _load_cfg()
+                display = cfg.get("display") if isinstance(cfg.get("display"), dict) else {}
+                sections = (
+                    display.get("sections")
+                    if isinstance(display.get("sections"), dict)
+                    else {}
+                )
+                display["show_reasoning"] = False
+                sections["thinking"] = "hidden"
+                display["sections"] = sections
+                cfg["display"] = display
+                _save_cfg(cfg)
                 if session:
                     session["show_reasoning"] = False
                 return _ok(rid, {"key": key, "value": "hide"})
diff --git a/ui-tui/src/__tests__/createSlashHandler.test.ts b/ui-tui/src/__tests__/createSlashHandler.test.ts
index 3ec340b8a..56128e388 100644
--- a/ui-tui/src/__tests__/createSlashHandler.test.ts
+++ b/ui-tui/src/__tests__/createSlashHandler.test.ts
@@ -76,6 +76,45 @@ describe('createSlashHandler', () => {
     })
   })
 
+  it('applies /reasoning hide to the thinking section immediately', async () => {
+    patchUiState({ sections: { thinking: 'expanded' }, showReasoning: true, sid: 'sid-abc' })
+    const ctx = buildCtx({
+      gateway: {
+        ...buildGateway(),
+        rpc: vi.fn(() => Promise.resolve({ value: 'hide' }))
+      }
+    })
+
+    expect(createSlashHandler(ctx)('/reasoning hide')).toBe(true)
+
+    await vi.waitFor(() => {
+      expect(getUiState().showReasoning).toBe(false)
+      expect(getUiState().sections.thinking).toBe('hidden')
+    })
+    expect(ctx.gateway.rpc).toHaveBeenCalledWith('config.set', {
+      key: 'reasoning',
+      session_id: 'sid-abc',
+      value: 'hide'
+    })
+  })
+
+  it('applies /reasoning show to the thinking section immediately', async () => {
+    patchUiState({ sections: { thinking: 'hidden' }, showReasoning: false, sid: 'sid-abc' })
+    const ctx = buildCtx({
+      gateway: {
+        ...buildGateway(),
+        rpc: vi.fn(() => Promise.resolve({ value: 'show' }))
+      }
+    })
+
+    expect(createSlashHandler(ctx)('/reasoning show')).toBe(true)
+
+    await vi.waitFor(() => {
+      expect(getUiState().showReasoning).toBe(true)
+      expect(getUiState().sections.thinking).toBe('expanded')
+    })
+  })
+
   it('opens the skills hub locally for bare /skills', () => {
     const ctx = buildCtx()
 
diff --git a/ui-tui/src/app/slash/commands/session.ts b/ui-tui/src/app/slash/commands/session.ts
index ecd1b7866..cfe84f942 100644
--- a/ui-tui/src/app/slash/commands/session.ts
+++ b/ui-tui/src/app/slash/commands/session.ts
@@ -332,7 +332,29 @@ export const sessionCommands: SlashCommand[] = [
 
       ctx.gateway
         .rpc<ConfigSetResponse>('config.set', { key: 'reasoning', session_id: ctx.sid, value: arg })
-        .then(ctx.guarded<ConfigSetResponse>(r => r.value && ctx.transcript.sys(`reasoning: ${r.value}`)))
+        .then(
+          ctx.guarded<ConfigSetResponse>(r => {
+            if (!r.value) {
+              return
+            }
+
+            if (r.value === 'hide') {
+              patchUiState(state => ({
+                ...state,
+                sections: { ...state.sections, thinking: 'hidden' },
+                showReasoning: false
+              }))
+            } else if (r.value === 'show') {
+              patchUiState(state => ({
+                ...state,
+                sections: { ...state.sections, thinking: 'expanded' },
+                showReasoning: true
+              }))
+            }
+
+            ctx.transcript.sys(`reasoning: ${r.value}`)
+          })
+        )
     }
   },
 
diff --git a/ui-tui/src/app/useMainApp.ts b/ui-tui/src/app/useMainApp.ts
index 70dc96fec..9ec18337b 100644
--- a/ui-tui/src/app/useMainApp.ts
+++ b/ui-tui/src/app/useMainApp.ts
@@ -711,6 +711,9 @@ export function useMainApp(gw: GatewayClient) {
   const anyPanelVisible = SECTION_NAMES.some(
     s => sectionMode(s, ui.detailsMode, ui.sections, ui.detailsModeCommandOverride) !== 'hidden'
   )
+  const thinkingPanelVisible = sectionMode('thinking', ui.detailsMode, ui.sections, ui.detailsModeCommandOverride) !== 'hidden'
+  const toolsPanelVisible = sectionMode('tools', ui.detailsMode, ui.sections, ui.detailsModeCommandOverride) !== 'hidden'
+  const activityPanelVisible = sectionMode('activity', ui.detailsMode, ui.sections, ui.detailsModeCommandOverride) !== 'hidden'
 
   const showProgressArea = useTurnSelector(state =>
     anyPanelVisible
@@ -718,12 +721,25 @@ export function useMainApp(gw: GatewayClient) {
           ui.busy ||
           state.outcome ||
           state.streamPendingTools.length ||
-          state.streamSegments.length ||
+          state.streamSegments.some(segment => {
+            const hasThinking = Boolean(segment.thinking?.trim())
+            const hasTrailTools = Boolean(segment.tools?.length)
+
+            if (segment.kind === 'trail' && !segment.text) {
+              return (thinkingPanelVisible && hasThinking) || ((toolsPanelVisible || activityPanelVisible) && hasTrailTools)
+            }
+
+            return (
+              Boolean(segment.text?.trim()) ||
+              (thinkingPanelVisible && hasThinking) ||
+              ((toolsPanelVisible || activityPanelVisible) && hasTrailTools)
+            )
+          }) ||
           state.subagents.length ||
           state.tools.length ||
           state.todos.length ||
           state.turnTrail.length ||
-          hasReasoning ||
+          (thinkingPanelVisible && hasReasoning) ||
           state.activity.length
         )
       : state.activity.some(item => item.tone !== 'info')