Python: Introduce agent name field regex (#9887)

### Motivation and Context

The agent name Pydantic field currently does not have any pattern regex
config. If a user creates an agent with an incorrect name (something
other than `0-9A-Za-z_-`) they will get a 400. To validate and error out
earlier, we're introducing the regex check when the field is validated.

Note, this is a non-breaking change because an invalid name errors out
further down in the processing -- we're adding this regex check so that
it can help a user/dev understand earlier in the processing that they
need to update their agent name.

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### Description

Add the regex field validation for the agent name as `AGENT_NAME_REGEX =
r"^[0-9A-Za-z_-]+$"`. Unlike the SK plugin/function names, this name can
contain a `-`. Updates unit tests.
- Closes #9340 

<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [X] The code builds clean without any errors or warnings
- [X] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [X] All unit tests pass, and I have added new tests where possible
- [X] I didn't break anyone 😄

python/semantic_kernel/agents/agent.py

@@ -11,6 +11,7 @@
 from semantic_kernel.kernel_pydantic import KernelBaseModel
 from semantic_kernel.utils.experimental_decorator import experimental_class
 from semantic_kernel.utils.naming import generate_random_ascii_name
+from semantic_kernel.utils.validation import AGENT_NAME_REGEX
 
 
 @experimental_class
@@ -32,7 +33,7 @@ class Agent(KernelBaseModel):
 
     id: str = Field(default_factory=lambda: str(uuid.uuid4()))
     description: str | None = None
-    name: str = Field(default_factory=lambda: f"agent_{generate_random_ascii_name()}")
+    name: str = Field(default_factory=lambda: f"agent_{generate_random_ascii_name()}", pattern=AGENT_NAME_REGEX)
     instructions: str | None = None
     kernel: Kernel = Field(default_factory=Kernel)
     channel_type: ClassVar[type[AgentChannel] | None] = None

python/semantic_kernel/utils/validation.py

@@ -1,5 +1,6 @@
 # Copyright (c) Microsoft. All rights reserved.
 
+AGENT_NAME_REGEX = r"^[0-9A-Za-z_-]+$"
 PLUGIN_NAME_REGEX = r"^[0-9A-Za-z_]+$"
 FUNCTION_NAME_REGEX = r"^[0-9A-Za-z_]+$"
 FULLY_QUALIFIED_FUNCTION_NAME = r"^(?P<plugin>[0-9A-Za-z_]+)[.](?P<function>[0-9A-Za-z_]+)$"

python/tests/unit/agents/test_agent.py

@@ -12,7 +12,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, name: str = "Test Agent", description: str = "A test agent", id: str = None):
+    def __init__(self, name: str = "Test-Agent", description: str = "A test agent", id: str = None):
         args = {
             "name": name,
             "description": description,
@@ -30,7 +30,7 @@ async def create_channel(self) -> AgentChannel:
 
 @pytest.mark.asyncio
 async def test_agent_initialization():
-    name = "Test Agent"
+    name = "TestAgent"
     description = "A test agent"
     id_value = str(uuid.uuid4())
 
@@ -68,21 +68,21 @@ async def test_create_channel():
 async def test_agent_equality():
     id_value = str(uuid.uuid4())
 
-    agent1 = MockAgent(name="Test Agent", description="A test agent", id=id_value)
-    agent2 = MockAgent(name="Test Agent", description="A test agent", id=id_value)
+    agent1 = MockAgent(name="TestAgent", description="A test agent", id=id_value)
+    agent2 = MockAgent(name="TestAgent", description="A test agent", id=id_value)
 
     assert agent1 == agent2
 
-    agent3 = MockAgent(name="Test Agent", description="A different description", id=id_value)
+    agent3 = MockAgent(name="TestAgent", description="A different description", id=id_value)
     assert agent1 != agent3
 
-    agent4 = MockAgent(name="Another Agent", description="A test agent", id=id_value)
+    agent4 = MockAgent(name="AnotherAgent", description="A test agent", id=id_value)
     assert agent1 != agent4
 
 
 @pytest.mark.asyncio
 async def test_agent_equality_different_type():
-    agent = MockAgent(name="Test Agent", description="A test agent", id=str(uuid.uuid4()))
+    agent = MockAgent(name="TestAgent", description="A test agent", id=str(uuid.uuid4()))
     non_agent = "Not an agent"
 
     assert agent != non_agent
@@ -92,10 +92,10 @@ async def test_agent_equality_different_type():
 async def test_agent_hash():
     id_value = str(uuid.uuid4())
 
-    agent1 = MockAgent(name="Test Agent", description="A test agent", id=id_value)
-    agent2 = MockAgent(name="Test Agent", description="A test agent", id=id_value)
+    agent1 = MockAgent(name="TestAgent", description="A test agent", id=id_value)
+    agent2 = MockAgent(name="TestAgent", description="A test agent", id=id_value)
 
     assert hash(agent1) == hash(agent2)
 
-    agent3 = MockAgent(name="Test Agent", description="A different description", id=id_value)
+    agent3 = MockAgent(name="TestAgent", description="A different description", id=id_value)
     assert hash(agent1) != hash(agent3)

python/tests/unit/agents/test_aggregator_termination_strategy.py

@@ -17,7 +17,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, id: str = None, name: str = "Test Agent", description: str = "A test agent"):
+    def __init__(self, id: str = None, name: str = "TestAgent", description: str = "A test agent"):
         args = {
             "name": name,
             "description": description,

python/tests/unit/agents/test_chat_completion_agent.py

@@ -3,6 +3,7 @@
 from unittest.mock import AsyncMock, create_autospec, patch
 
 import pytest
+from pydantic import ValidationError
 
 from semantic_kernel.agents import ChatCompletionAgent
 from semantic_kernel.agents.channels.chat_history_channel import ChatHistoryChannel
@@ -33,31 +34,43 @@ async def mock_response(chat_history, settings, kernel):
 async def test_initialization():
     agent = ChatCompletionAgent(
         service_id="test_service",
-        name="Test Agent",
+        name="TestAgent",
         id="test_id",
         description="Test Description",
         instructions="Test Instructions",
     )
 
     assert agent.service_id == "test_service"
-    assert agent.name == "Test Agent"
+    assert agent.name == "TestAgent"
     assert agent.id == "test_id"
     assert agent.description == "Test Description"
     assert agent.instructions == "Test Instructions"
 
 
+@pytest.mark.asyncio
+async def test_initialization_invalid_name_throws():
+    with pytest.raises(ValidationError):
+        _ = ChatCompletionAgent(
+            service_id="test_service",
+            name="Test Agent",
+            id="test_id",
+            description="Test Description",
+            instructions="Test Instructions",
+        )
+
+
 @pytest.mark.asyncio
 async def test_initialization_no_service_id():
     agent = ChatCompletionAgent(
-        name="Test Agent",
+        name="TestAgent",
         id="test_id",
         description="Test Description",
         instructions="Test Instructions",
     )
 
     assert agent.service_id == "default"
     assert agent.kernel is not None
-    assert agent.name == "Test Agent"
+    assert agent.name == "TestAgent"
     assert agent.id == "test_id"
     assert agent.description == "Test Description"
     assert agent.instructions == "Test Instructions"
@@ -67,15 +80,15 @@ async def test_initialization_no_service_id():
 async def test_initialization_with_kernel(kernel: Kernel):
     agent = ChatCompletionAgent(
         kernel=kernel,
-        name="Test Agent",
+        name="TestAgent",
         id="test_id",
         description="Test Description",
         instructions="Test Instructions",
     )
 
     assert agent.service_id == "default"
     assert kernel == agent.kernel
-    assert agent.name == "Test Agent"
+    assert agent.name == "TestAgent"
     assert agent.id == "test_id"
     assert agent.description == "Test Description"
     assert agent.instructions == "Test Instructions"
@@ -89,7 +102,7 @@ async def test_invoke():
         return_value=[ChatMessageContent(role=AuthorRole.SYSTEM, content="Processed Message")]
     )
     agent = ChatCompletionAgent(
-        kernel=kernel, service_id="test_service", name="Test Agent", instructions="Test Instructions"
+        kernel=kernel, service_id="test_service", name="TestAgent", instructions="Test Instructions"
     )
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
@@ -105,7 +118,7 @@ async def test_invoke_tool_call_added():
     kernel = create_autospec(Kernel)
     chat_completion_service = create_autospec(ChatCompletionClientBase)
     kernel.get_service.return_value = chat_completion_service
-    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="Test Agent")
+    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="TestAgent")
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
 
@@ -128,15 +141,15 @@ async def mock_get_chat_message_contents(chat_history, settings, kernel):
     assert len(history.messages) == 3
     assert history.messages[1].content == "Processed Message 1"
     assert history.messages[2].content == "Processed Message 2"
-    assert history.messages[1].name == "Test Agent"
-    assert history.messages[2].name == "Test Agent"
+    assert history.messages[1].name == "TestAgent"
+    assert history.messages[2].name == "TestAgent"
 
 
 @pytest.mark.asyncio
 async def test_invoke_no_service_throws():
     kernel = create_autospec(Kernel)
     kernel.get_service.return_value = None
-    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="Test Agent")
+    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="TestAgent")
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
 
@@ -150,7 +163,7 @@ async def test_invoke_stream():
     kernel = create_autospec(Kernel)
     kernel.get_service.return_value = create_autospec(ChatCompletionClientBase)
 
-    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="Test Agent")
+    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="TestAgent")
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
 
@@ -172,7 +185,7 @@ async def test_invoke_stream_tool_call_added(mock_streaming_chat_completion_resp
     kernel = create_autospec(Kernel)
     chat_completion_service = create_autospec(ChatCompletionClientBase)
     kernel.get_service.return_value = chat_completion_service
-    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="Test Agent")
+    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="TestAgent")
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
 
@@ -190,7 +203,7 @@ async def test_invoke_stream_tool_call_added(mock_streaming_chat_completion_resp
 async def test_invoke_stream_no_service_throws():
     kernel = create_autospec(Kernel)
     kernel.get_service.return_value = None
-    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="Test Agent")
+    agent = ChatCompletionAgent(kernel=kernel, service_id="test_service", name="TestAgent")
 
     history = ChatHistory(messages=[ChatMessageContent(role=AuthorRole.USER, content="Initial Message")])
 

python/tests/unit/agents/test_kernel_function_selection_strategy.py

@@ -18,7 +18,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, id: str = None, name: str = "Test Agent", description: str = "A test agent"):
+    def __init__(self, id: str = None, name: str = "TestAgent", description: str = "A test agent"):
         args = {
             "name": name,
             "description": description,
@@ -37,14 +37,14 @@ async def create_channel(self) -> AgentChannel:
 @pytest.fixture
 def agents():
     """Fixture that provides a list of mock agents."""
-    return [MockAgent(id=f"agent-{i}", name=f"Agent-{i}") for i in range(3)]
+    return [MockAgent(id=f"agent-{i}", name=f"Agent_{i}") for i in range(3)]
 
 
 @pytest.mark.asyncio
 async def test_kernel_function_selection_next_success(agents):
     history = [MagicMock(spec=ChatMessageContent)]
     mock_function = AsyncMock(spec=KernelFunction)
-    mock_function.invoke.return_value = MagicMock(value="Agent-1")
+    mock_function.invoke.return_value = MagicMock(value="Agent_1")
     mock_kernel = MagicMock(spec=Kernel)
 
     strategy = KernelFunctionSelectionStrategy(
@@ -53,7 +53,7 @@ async def test_kernel_function_selection_next_success(agents):
 
     selected_agent = await strategy.next(agents, history)
 
-    assert selected_agent.name == "Agent-1"
+    assert selected_agent.name == "Agent_1"
     mock_function.invoke.assert_awaited_once()
 
 
@@ -115,7 +115,7 @@ async def test_kernel_function_selection_next_exception_during_invoke(agents):
 async def test_kernel_function_selection_result_parser_is_async(agents):
     history = [MagicMock(spec=ChatMessageContent)]
     mock_function = AsyncMock(spec=KernelFunction)
-    mock_function.invoke.return_value = MagicMock(value="Agent-2")
+    mock_function.invoke.return_value = MagicMock(value="Agent_2")
     mock_kernel = MagicMock(spec=Kernel)
 
     async def async_result_parser(result):
@@ -127,5 +127,5 @@ async def async_result_parser(result):
 
     selected_agent = await strategy.next(agents, history)
 
-    assert selected_agent.name == "Agent-2"
+    assert selected_agent.name == "Agent_2"
     mock_function.invoke.assert_awaited_once()

python/tests/unit/agents/test_kernel_function_termination_strategy.py

@@ -16,7 +16,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, id: str = None, name: str = "Test Agent", description: str = "A test agent"):
+    def __init__(self, id: str = None, name: str = "TestAgent", description: str = "A test agent"):
         args = {
             "name": name,
             "description": description,

python/tests/unit/agents/test_sequential_strategy_selection.py

@@ -12,7 +12,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, id: str = None, name: str = "Test Agent", description: str = "A test agent"):
+    def __init__(self, id: str = None, name: str = "TestAgent", description: str = "A test agent"):
         args = {
             "name": name,
             "description": description,

python/tests/unit/agents/test_termination_strategy.py

@@ -13,7 +13,7 @@
 class MockAgent(Agent):
     """A mock agent for testing purposes."""
 
-    def __init__(self, id: str = None, name: str = "Test Agent", description: str = "A test agent"):
+    def __init__(self, id: str = None, name: str = "TestAgent", description: str = "A test agent"):
         args = {
             "name": name,
             "description": description,