Python: [Breaking] removed pydantic from types and workflows (#917)

* removed pydantic from types

* fix test

* fix test

* fix tests

* fix assistants client

* Remove Pydantic usage from workflow code.

* updated pydantic removal

* updated lock and test fixes

* fix mypy

* updated build system

* updated chat client parsing

* fix broken test

---------

Co-authored-by: Evan Mattson <evan.mattson@microsoft.com>

python/packages/a2a/agent_framework_a2a/_agent.py

@@ -68,9 +68,6 @@ class A2AAgent(BaseAgent):
     Can be initialized with a URL, AgentCard, or existing A2A Client instance.
     """
 
-    client: Client
-    _http_client: httpx.AsyncClient | None = None
-
     def __init__(
         self,
         *,
@@ -81,6 +78,7 @@ class A2AAgent(BaseAgent):
         url: str | None = None,
         client: Client | None = None,
         http_client: httpx.AsyncClient | None = None,
+        **kwargs: Any,
     ) -> None:
         """Initialize the A2AAgent.
 
@@ -92,42 +90,40 @@ class A2AAgent(BaseAgent):
             url: The URL for the A2A server.
             client: The A2A client for the agent.
             http_client: Optional httpx.AsyncClient to use.
+            kwargs: any additional properties, passed to BaseAgent.
         """
-        if client is None:
-            if agent_card is None:
-                if url is None:
-                    raise ValueError("Either agent_card or url must be provided")
-                # Create minimal agent card from URL
-                agent_card = minimal_agent_card(url, [TransportProtocol.jsonrpc])
+        super().__init__(id=id, name=name, description=description, **kwargs)
+        self._http_client: httpx.AsyncClient | None = http_client
+        if client is not None:
+            self.client = client
+            self._close_http_client = True
+            return
+        if agent_card is None:
+            if url is None:
+                raise ValueError("Either agent_card or url must be provided")
+            # Create minimal agent card from URL
+            agent_card = minimal_agent_card(url, [TransportProtocol.jsonrpc])
 
-            # Create or use provided httpx client
-            if http_client is None:
-                timeout = httpx.Timeout(
-                    connect=10.0,  # 10 seconds to establish connection
-                    read=60.0,  # 60 seconds to read response (A2A operations can take time)
-                    write=10.0,  # 10 seconds to send request
-                    pool=5.0,  # 5 seconds to get connection from pool
-                )
-                headers = prepend_agent_framework_to_user_agent()
-                http_client = httpx.AsyncClient(timeout=timeout, headers=headers)
-                self._http_client = http_client  # Store for cleanup
-
-            # Create A2A client using factory
-            config = ClientConfig(
-                httpx_client=http_client,
-                supported_transports=[TransportProtocol.jsonrpc],
+        # Create or use provided httpx client
+        if http_client is None:
+            timeout = httpx.Timeout(
+                connect=10.0,  # 10 seconds to establish connection
+                read=60.0,  # 60 seconds to read response (A2A operations can take time)
+                write=10.0,  # 10 seconds to send request
+                pool=5.0,  # 5 seconds to get connection from pool
             )
-            factory = ClientFactory(config)
-            client = factory.create(agent_card)
+            headers = prepend_agent_framework_to_user_agent()
+            http_client = httpx.AsyncClient(timeout=timeout, headers=headers)
+            self._http_client = http_client  # Store for cleanup
+            self._close_http_client = True
 
-        args: dict[str, Any] = {"client": client}
-        if name:
-            args["name"] = name
-        if id:
-            args["id"] = id
-        if description:
-            args["description"] = description
-        super().__init__(**args)
+        # Create A2A client using factory
+        config = ClientConfig(
+            httpx_client=http_client,
+            supported_transports=[TransportProtocol.jsonrpc],
+        )
+        factory = ClientFactory(config)
+        self.client = factory.create(agent_card)
 
     async def __aenter__(self) -> "A2AAgent":
         """Async context manager entry."""
@@ -141,7 +137,7 @@ class A2AAgent(BaseAgent):
     ) -> None:
         """Async context manager exit with httpx client cleanup."""
         # Close our httpx client if we created it
-        if self._http_client is not None:
+        if self._http_client is not None and self._close_http_client:
             await self._http_client.aclose()
 
     async def run(

python/packages/a2a/tests/test_a2a_agent.py

@@ -90,14 +90,14 @@ def mock_a2a_client() -> MockA2AClient:
 @fixture
 def a2a_agent(mock_a2a_client: MockA2AClient) -> A2AAgent:
     """Fixture that provides an A2AAgent with a mock client."""
-    return A2AAgent.model_construct(name="Test Agent", id="test-agent", client=mock_a2a_client, _http_client=None)
+    return A2AAgent(name="Test Agent", id="test-agent", client=mock_a2a_client, http_client=None)
 
 
 def test_a2a_agent_initialization_with_client(mock_a2a_client: MockA2AClient) -> None:
     """Test A2AAgent initialization with provided client."""
     # Use model_construct to bypass Pydantic validation for mock objects
-    agent = A2AAgent.model_construct(
-        name="Test Agent", id="test-agent-123", description="A test agent", client=mock_a2a_client, _http_client=None
+    agent = A2AAgent(
+        name="Test Agent", id="test-agent-123", description="A test agent", client=mock_a2a_client, http_client=None
     )
 
     assert agent.name == "Test Agent"
@@ -266,7 +266,7 @@ def test_get_uri_data_invalid_uri() -> None:
 def test_a2a_parts_to_contents_conversion(a2a_agent: A2AAgent) -> None:
     """Test A2A parts to contents conversion."""
 
-    agent = A2AAgent.model_construct(name="Test Agent", client=MockA2AClient(), _http_client=None)
+    agent = A2AAgent(name="Test Agent", client=MockA2AClient(), _http_client=None)
 
     # Create A2A parts
     parts = [Part(root=TextPart(text="First part")), Part(root=TextPart(text="Second part"))]
@@ -369,7 +369,8 @@ async def test_context_manager_cleanup() -> None:
     mock_http_client = AsyncMock()
     mock_a2a_client = MagicMock()
 
-    agent = A2AAgent.model_construct(client=mock_a2a_client, _http_client=mock_http_client)
+    agent = A2AAgent(client=mock_a2a_client)
+    agent._http_client = mock_http_client
 
     # Test context manager cleanup
     async with agent:
@@ -384,7 +385,7 @@ async def test_context_manager_no_cleanup_when_no_http_client() -> None:
 
     mock_a2a_client = MagicMock()
 
-    agent = A2AAgent.model_construct(client=mock_a2a_client, _http_client=None)
+    agent = A2AAgent(client=mock_a2a_client, _http_client=None)
 
     # This should not raise any errors
     async with agent:
@@ -394,7 +395,7 @@ async def test_context_manager_no_cleanup_when_no_http_client() -> None:
 def test_chat_message_to_a2a_message_with_multiple_contents() -> None:
     """Test conversion of ChatMessage with multiple contents."""
 
-    agent = A2AAgent.model_construct(client=MagicMock(), _http_client=None)
+    agent = A2AAgent(client=MagicMock(), _http_client=None)
 
     # Create message with multiple content types
     message = ChatMessage(
@@ -422,7 +423,7 @@ def test_chat_message_to_a2a_message_with_multiple_contents() -> None:
 def test_a2a_parts_to_contents_with_data_part() -> None:
     """Test conversion of A2A DataPart."""
 
-    agent = A2AAgent.model_construct(client=MagicMock(), _http_client=None)
+    agent = A2AAgent(client=MagicMock(), _http_client=None)
 
     # Create DataPart
     data_part = Part(root=DataPart(data={"key": "value", "number": 42}, metadata={"source": "test"}))
@@ -438,7 +439,7 @@ def test_a2a_parts_to_contents_with_data_part() -> None:
 
 def test_a2a_parts_to_contents_unknown_part_kind() -> None:
     """Test error handling for unknown A2A part kind."""
-    agent = A2AAgent.model_construct(client=MagicMock(), _http_client=None)
+    agent = A2AAgent(client=MagicMock(), _http_client=None)
 
     # Create a mock part with unknown kind
     mock_part = MagicMock()
@@ -451,7 +452,7 @@ def test_a2a_parts_to_contents_unknown_part_kind() -> None:
 def test_chat_message_to_a2a_message_with_hosted_file() -> None:
     """Test conversion of ChatMessage with HostedFileContent to A2A message."""
 
-    agent = A2AAgent.model_construct(client=MagicMock(), _http_client=None)
+    agent = A2AAgent(client=MagicMock(), _http_client=None)
 
     # Create message with hosted file content
     message = ChatMessage(
@@ -477,7 +478,7 @@ def test_chat_message_to_a2a_message_with_hosted_file() -> None:
 def test_a2a_parts_to_contents_with_hosted_file_uri() -> None:
     """Test conversion of A2A FilePart with hosted file URI back to UriContent."""
 
-    agent = A2AAgent.model_construct(client=MagicMock(), _http_client=None)
+    agent = A2AAgent(client=MagicMock(), _http_client=None)
 
     # Create FilePart with hosted file URI (simulating what A2A would send back)
     file_part = Part(