diff --git a/src/components/chat/utils/toolGrouping.ts b/src/components/chat/utils/toolGrouping.ts
index c9d56433..6a964571 100644
--- a/src/components/chat/utils/toolGrouping.ts
+++ b/src/components/chat/utils/toolGrouping.ts
@@ -1,6 +1,6 @@
 import type { ChatMessage } from '../types/types';
 
-export const TOOL_GROUP_THRESHOLD = 3;
+export const TOOL_GROUP_THRESHOLD = 2;
 
 export interface ToolGroupItem {
   _isGroup: true;
@@ -19,7 +19,17 @@ function isGroupableToolMessage(message: ChatMessage): message is ChatMessage &
   return Boolean(message.isToolUse && message.toolName && !message.isSubagentContainer);
 }
 
-export function groupConsecutiveTools(messages: ChatMessage[]): MessageListItem[] {
+// Messages that render nothing (e.g. reasoning hidden when showThinking is off)
+// shouldn't split an otherwise-continuous run of the same tool — providers like
+// Codex interleave hidden reasoning between consecutive tool calls.
+function rendersNothing(message: ChatMessage, showThinking: boolean): boolean {
+  return Boolean(message.isThinking && !showThinking);
+}
+
+export function groupConsecutiveTools(
+  messages: ChatMessage[],
+  showThinking: boolean = true,
+): MessageListItem[] {
   const items: MessageListItem[] = [];
   let index = 0;
 
@@ -35,13 +45,22 @@ export function groupConsecutiveTools(messages: ChatMessage[]): MessageListItem[
     const run: ChatMessage[] = [message];
     let nextIndex = index + 1;
 
-    while (
-      nextIndex < messages.length &&
-      isGroupableToolMessage(messages[nextIndex]) &&
-      messages[nextIndex].toolName === message.toolName
-    ) {
-      run.push(messages[nextIndex]);
-      nextIndex += 1;
+    while (nextIndex < messages.length) {
+      const candidate = messages[nextIndex];
+
+      // Skip invisible interleaved messages so they don't break the run.
+      if (rendersNothing(candidate, showThinking)) {
+        nextIndex += 1;
+        continue;
+      }
+
+      if (isGroupableToolMessage(candidate) && candidate.toolName === message.toolName) {
+        run.push(candidate);
+        nextIndex += 1;
+        continue;
+      }
+
+      break;
     }
 
     if (run.length >= TOOL_GROUP_THRESHOLD) {
diff --git a/src/components/chat/view/subcomponents/ChatMessagesPane.tsx b/src/components/chat/view/subcomponents/ChatMessagesPane.tsx
index bb61096a..55029c58 100644
--- a/src/components/chat/view/subcomponents/ChatMessagesPane.tsx
+++ b/src/components/chat/view/subcomponents/ChatMessagesPane.tsx
@@ -120,7 +120,10 @@ function ChatMessagesPane({
   const messageKeyMapRef = useRef<WeakMap<ChatMessage, string>>(new WeakMap());
   const allocatedKeysRef = useRef<Set<string>>(new Set());
   const generatedMessageKeyCounterRef = useRef(0);
-  const groupedVisibleMessages = useMemo(() => groupConsecutiveTools(visibleMessages), [visibleMessages]);
+  const groupedVisibleMessages = useMemo(
+    () => groupConsecutiveTools(visibleMessages, Boolean(showThinking)),
+    [visibleMessages, showThinking],
+  );
 
   // Keep keys stable across prepends so existing MessageComponent instances retain local state.
   const getMessageKey = useCallback((message: ChatMessage) => {