diff --git a/pubspec.yaml b/pubspec.yaml
index 5d005f1a..25835bf0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -18,7 +18,7 @@ repository: https://github.com/postmeridiem/clide
 
 # Pre-push line-coverage floor. Ratchets up only — see D-66.
 # Reading: `awk -F: '/^coverage_floor:/ {gsub(/ /,"",$2); print $2}' pubspec.yaml`.
-coverage_floor: 79
+coverage_floor: 80
 
 # Project metadata (was project.yaml, folded in per D-056).
 # version: above is the single source of truth. The Makefile reads
diff --git a/test/builtin/default_layout/widget_test.dart b/test/builtin/default_layout/widget_test.dart
index 6eb7c343..1b110ece 100644
--- a/test/builtin/default_layout/widget_test.dart
+++ b/test/builtin/default_layout/widget_test.dart
@@ -45,5 +45,114 @@ void main() {
         hasLength(1),
       );
     });
+
+    test('all commands return not-activated errors before activate', () async {
+      final ext = DefaultLayoutExtension();
+      final cmds = ext.contributions.whereType<CommandContribution>().toList();
+      // 12+ commands including the 5 sidebar.section.N variants.
+      expect(cmds.length, greaterThan(10));
+      for (final cmd in cmds) {
+        final r = await cmd.run(const []);
+        expect(r.ok, isFalse, reason: 'expected ${cmd.command} to fail pre-activate');
+        expect(r.error!.message, contains('not activated'));
+      }
+    });
+
+    test('palette.toggle flips palette open state', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      expect(f.services.palette.isOpen, isFalse);
+      final r1 = await f.services.commands.execute('palette.toggle');
+      expect(r1.ok, isTrue);
+      expect(r1.data['open'], isTrue);
+      expect(f.services.palette.isOpen, isTrue);
+      final r2 = await f.services.commands.execute('palette.toggle');
+      expect(r2.data['open'], isFalse);
+    });
+
+    test('sidebar.collapse + context.collapse toggle their respective slots', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      expect(f.services.arrangement.isCollapsed(Slots.sidebar), isFalse);
+      await f.services.commands.execute('sidebar.collapse');
+      expect(f.services.arrangement.isCollapsed(Slots.sidebar), isTrue);
+      await f.services.commands.execute('sidebar.collapse');
+      expect(f.services.arrangement.isCollapsed(Slots.sidebar), isFalse);
+      await f.services.commands.execute('context.collapse');
+      expect(f.services.arrangement.isCollapsed(Slots.contextPanel), isTrue);
+    });
+
+    test('panel.focus.{left,middle,right} expand collapsed sides + set focus', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      // Collapse both side panels first.
+      f.services.arrangement.setCollapsed(Slots.sidebar, true);
+      f.services.arrangement.setCollapsed(Slots.contextPanel, true);
+      // Focus left: re-expands sidebar.
+      await f.services.commands.execute('panel.focus.left');
+      expect(f.services.arrangement.isCollapsed(Slots.sidebar), isFalse);
+      // Focus right: re-expands context.
+      await f.services.commands.execute('panel.focus.right');
+      expect(f.services.arrangement.isCollapsed(Slots.contextPanel), isFalse);
+      // Focus middle: no expansion needed, just sets focus.
+      final r = await f.services.commands.execute('panel.focus.middle');
+      expect(r.ok, isTrue);
+    });
+
+    test('panel.focusMode toggles focus mode on the active slot', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      expect(f.services.arrangement.isInFocusMode, isFalse);
+      await f.services.commands.execute('panel.focusMode');
+      expect(f.services.arrangement.isInFocusMode, isTrue);
+    });
+
+    test('panel.focusMode.exit unwinds focus-mode → editor → palette', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      // Focus mode: exit clears it.
+      f.services.arrangement.toggleFocusMode(Slots.workspace);
+      expect(f.services.arrangement.isInFocusMode, isTrue);
+      await f.services.commands.execute('panel.focusMode.exit');
+      expect(f.services.arrangement.isInFocusMode, isFalse);
+      // Editor open: exit closes it.
+      f.services.arrangement.openEditor();
+      expect(f.services.arrangement.editorOpen, isTrue);
+      await f.services.commands.execute('panel.focusMode.exit');
+      expect(f.services.arrangement.editorOpen, isFalse);
+      // Palette open: exit closes it.
+      f.services.palette.toggle();
+      expect(f.services.palette.isOpen, isTrue);
+      await f.services.commands.execute('panel.focusMode.exit');
+      expect(f.services.palette.isOpen, isFalse);
+      // Nothing to exit: returns ok with empty data.
+      final noop = await f.services.commands.execute('panel.focusMode.exit');
+      expect(noop.ok, isTrue);
+    });
+
+    test('editor.open and editor.close toggle the editor split', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      expect(f.services.arrangement.editorOpen, isFalse);
+      await f.services.commands.execute('editor.open');
+      expect(f.services.arrangement.editorOpen, isTrue);
+      await f.services.commands.execute('editor.close');
+      expect(f.services.arrangement.editorOpen, isFalse);
+      // editor.close when already closed → ok no-op.
+      final noop = await f.services.commands.execute('editor.close');
+      expect(noop.ok, isTrue);
+    });
+
+    test('sidebar.section.N activates the Nth sidebar tab', () async {
+      f.services.extensions.register(DefaultLayoutExtension());
+      await f.services.extensions.activateAll();
+      // Collapse sidebar so we exercise the re-expand branch.
+      f.services.arrangement.setCollapsed(Slots.sidebar, true);
+      // No-op when no tabs are contributed.
+      final r = await f.services.commands.execute('sidebar.section.1');
+      expect(r.ok, isTrue);
+      // Sidebar auto-expanded.
+      expect(f.services.arrangement.isCollapsed(Slots.sidebar), isFalse);
+    });
   });
 }