diff --git a/python/docs/src/user-guide/agentchat-user-guide/tutorial/agents.ipynb b/python/docs/src/user-guide/agentchat-user-guide/tutorial/agents.ipynb
index cb081f552..efd530e1b 100644
--- a/python/docs/src/user-guide/agentchat-user-guide/tutorial/agents.ipynb
+++ b/python/docs/src/user-guide/agentchat-user-guide/tutorial/agents.ipynb
@@ -433,6 +433,13 @@
     "when agent behavior needs to be consistent across different models.\n",
     "This should be done at the model client level.\n",
     "\n",
+    "```{important}\n",
+    "When using {py:class}`~autogen_agentchat.tools.AgentTool` or {py:class}`~autogen_agentchat.tools.TeamTool`,\n",
+    "you **must** disable parallel tool calls to avoid concurrency issues.\n",
+    "These tools cannot run concurrently as agents and teams maintain internal state\n",
+    "that would conflict with parallel execution.\n",
+    "```\n",
+    "\n",
     "For {py:class}`~autogen_ext.models.openai.OpenAIChatCompletionClient` and {py:class}`~autogen_ext.models.openai.AzureOpenAIChatCompletionClient`,\n",
     "set `parallel_tool_calls=False` to disable parallel tool calls."
    ]
diff --git a/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_agent.py b/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_agent.py
index e4d51195d..d7ef31418 100644
--- a/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_agent.py
+++ b/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_agent.py
@@ -22,6 +22,13 @@ class AgentTool(TaskRunnerTool, Component[AgentToolConfig]):
 
     The tool returns the result of the task execution as a :class:`~autogen_agentchat.base.TaskResult` object.
 
+    .. important::
+        When using AgentTool, you **must** disable parallel tool calls in the model client configuration
+        to avoid concurrency issues. Agents cannot run concurrently as they maintain internal state
+        that would conflict with parallel execution. For example, set ``parallel_tool_calls=False``
+        for :class:`~autogen_ext.models.openai.OpenAIChatCompletionClient` and
+        :class:`~autogen_ext.models.openai.AzureOpenAIChatCompletionClient`.
+
     Args:
         agent (BaseChatAgent): The agent to be used for running the task.
         return_value_as_last_message (bool): Whether to use the last message content of the task result
@@ -51,9 +58,12 @@ class AgentTool(TaskRunnerTool, Component[AgentToolConfig]):
                     system_message="Write well.",
                 )
                 writer_tool = AgentTool(agent=writer)
+
+                # Create model client with parallel tool calls disabled for the main agent
+                main_model_client = OpenAIChatCompletionClient(model="gpt-4", parallel_tool_calls=False)
                 assistant = AssistantAgent(
                     name="assistant",
-                    model_client=model_client,
+                    model_client=main_model_client,
                     tools=[writer_tool],
                     system_message="You are a helpful assistant.",
                 )
diff --git a/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_team.py b/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_team.py
index 28bbb0daa..4a7167eb6 100644
--- a/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_team.py
+++ b/python/packages/autogen-agentchat/src/autogen_agentchat/tools/_team.py
@@ -25,6 +25,13 @@ class TeamTool(TaskRunnerTool, Component[TeamToolConfig]):
 
     The tool returns the result of the task execution as a :class:`~autogen_agentchat.base.TaskResult` object.
 
+    .. important::
+        When using TeamTool, you **must** disable parallel tool calls in the model client configuration
+        to avoid concurrency issues. Teams cannot run concurrently as they maintain internal state
+        that would conflict with parallel execution. For example, set ``parallel_tool_calls=False``
+        for :class:`~autogen_ext.models.openai.OpenAIChatCompletionClient` and
+        :class:`~autogen_ext.models.openai.AzureOpenAIChatCompletionClient`.
+
     Args:
         team (BaseGroupChat): The team to be used for running the task.
         name (str): The name of the tool.
@@ -48,6 +55,7 @@ class TeamTool(TaskRunnerTool, Component[TeamToolConfig]):
 
 
             async def main() -> None:
+                # Disable parallel tool calls when using TeamTool
                 model_client = OllamaChatCompletionClient(model="llama3.2")
 
                 writer = AssistantAgent(name="writer", model_client=model_client, system_message="You are a helpful assistant.")
@@ -65,12 +73,17 @@ class TeamTool(TaskRunnerTool, Component[TeamToolConfig]):
 
                 # Create a TeamTool that uses the team to run tasks, returning the last message as the result.
                 tool = TeamTool(
-                    team=team, name="writing_team", description="A tool for writing tasks.", return_value_as_last_message=True
+                    team=team,
+                    name="writing_team",
+                    description="A tool for writing tasks.",
+                    return_value_as_last_message=True,
                 )
 
+                # Create model client with parallel tool calls disabled for the main agent
+                main_model_client = OllamaChatCompletionClient(model="llama3.2", parallel_tool_calls=False)
                 main_agent = AssistantAgent(
                     name="main_agent",
-                    model_client=model_client,
+                    model_client=main_model_client,
                     system_message="You are a helpful assistant that can use the writing tool.",
                     tools=[tool],
                 )