diff --git a/routes/chat.py b/routes/chat.py
index 764c0fc..6d98388 100644
--- a/routes/chat.py
+++ b/routes/chat.py
@@ -93,6 +93,7 @@ async def enhanced_generate_stream_response(
                 chunk_id = 0
                 message_tag = ""
                 current_tool_name = ""
+                current_is_ui_tool = False
                 last_answer_first_char_duration_ms = None
                 waiting_for_answer_first_char = False
                 agent, checkpointer, sandbox = await init_agent(config)
@@ -114,9 +115,12 @@ async def enhanced_generate_stream_response(
                                 chunk_args = tool_call_chunk.get("args") if isinstance(tool_call_chunk, dict) else getattr(tool_call_chunk, "args", None)
                                 if chunk_name:
                                     current_tool_name = chunk_name
+                                    current_is_ui_tool = False
                                 # Always output ui:// protocol tool calls even when tool_response is disabled
-                                is_ui_tool = isinstance(chunk_args, str) and '"ui://' in (chunk_args or '')
-                                if config.tool_response or is_ui_tool:
+                                # Detect ui:// in chunk args; once detected, all subsequent chunks for this tool are UI
+                                if isinstance(chunk_args, str) and '"ui://' in chunk_args:
+                                    current_is_ui_tool = True
+                                if config.tool_response or current_is_ui_tool:
                                     if chunk_name:
                                         new_content = f"[{message_tag}] {chunk_name}\n"
                                     if chunk_args: