diff --git a/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddSheet.svelte b/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddSheet.svelte
index c78b42ea88..6b4f12376f 100644
--- a/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddSheet.svelte
+++ b/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddSheet.svelte
@@ -281,7 +281,7 @@
 		</span>
 
 		<Checkbox
-			{checked}
+			checked={checked && !indeterminate}
 			class="{ICON_CLASS_DEFAULT} shrink-0"
 			{indeterminate}
 			onCheckedChange={() => toolsPanel.toggleGroupByKey(group.key)}
diff --git a/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddToolsSubmenu.svelte b/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddToolsSubmenu.svelte
index b6e539b345..6f32ad0920 100644
--- a/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddToolsSubmenu.svelte
+++ b/tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddToolsSubmenu.svelte
@@ -79,7 +79,7 @@
 	{@const isExpanded = toolsPanel.expandedGroups.has(group.key)}
 	{@const checked = toolsPanel.isGroupChecked(group)}
 	{@const enabledCount = toolsPanel.getEnabledToolCount(group)}
-	// parent on but nothing under it enabled, or partially enabled: show mixed state
+	<!-- mixed state: parent on but nothing or only part of it enabled -->
 	{@const indeterminate =
 		group.tools.length > 0 && (enabledCount === 0 ? checked : enabledCount < group.tools.length)}
 	{@const favicon = toolsPanel.getFavicon(group)}
@@ -124,7 +124,7 @@
 					{#snippet child({ props })}
 						<Checkbox
 							{...props}
-							{checked}
+							checked={checked && !indeterminate}
 							class="mr-2 {ICON_CLASS_DEFAULT} shrink-0"
 							{indeterminate}
 							onCheckedChange={() => toolsPanel.toggleGroupByKey(group.key)}