refactor streaming response handling in Formatter class; implement lock for concurrent Live panel management and improve error handling

swarms/structs/agent.py

@@ -1144,7 +1144,6 @@ class Agent:
                             self.tool_call_completed = True
                             # Reset expecting_tool_call so subsequent requests can stream
                             self.expecting_tool_call = False
-
                         # Handle MCP tools
                         if (
                             exists(self.mcp_url)
@@ -2558,7 +2557,6 @@ class Agent:
         try:
             # Decide whether streaming should be used for this call
             streaming_enabled = self.streaming_on and not getattr(self, "expecting_tool_call", False)
-
             # Set streaming parameter in LLM if streaming is enabled for this call
             if streaming_enabled and hasattr(self.llm, "stream"):
                 original_stream = self.llm.stream
@@ -2573,7 +2571,7 @@ class Agent:
                         task=task, *args, **kwargs
                     )
 
-                # If we get a streaming response, handle it with the streaming panel
+                # If we get a streaming response, handle it with the new streaming panel
                 if hasattr(
                     streaming_response, "__iter__"
                 ) and not isinstance(streaming_response, str):
@@ -3079,11 +3077,9 @@ class Agent:
                 Focus on the key information and insights that would be most relevant to the user's original request.
                 {self.run_task}
                 If there are any errors or issues, highlight them prominently.
-
                 Tool Output:
                 {output}
                 """
-
             # Stream the tool summary only if the agent is configured for streaming
             if self.streaming_on and self.print_on:
                 # Handle streaming response with streaming panel

swarms/utils/formatter.py

@@ -9,6 +9,12 @@ from rich.progress import Progress, SpinnerColumn, TextColumn
 from rich.table import Table
 from rich.text import Text
 
+# Global lock to ensure only a single Rich Live context is active at any moment.
+# Rich's Live render is **not** thread-safe; concurrent Live contexts on the same
+# console raise runtime errors. Using a module-level lock serialises access and
+# prevents crashes when multiple agents stream simultaneously in different
+# threads (e.g., in ConcurrentWorkflow).
+live_render_lock = threading.Lock()
 
 def choose_random_color():
     import random
@@ -209,6 +215,10 @@ class Formatter:
         complete_response = ""
         chunks_collected = []
 
+        # Acquire the lock so that only one Live panel is active at a time.
+        # Other threads will wait here until the current streaming completes,
+        # avoiding Rich.Live concurrency errors.
+        with live_render_lock:
             # TRUE streaming with Rich's automatic text wrapping
             with Live(
                 create_streaming_panel(streaming_text),