Python: [BREAKING] Simplify API: ChatAgent -> Agent, ChatMessage -> Message (#3747)

* [BREAKING] Rename ChatAgent -> Agent, ChatMessage -> Message, ChatClientProtocol -> SupportsChatGetResponse

Simplify the public API by removing redundant 'Chat' prefix from core types:
- ChatAgent -> Agent
- RawChatAgent -> RawAgent
- ChatMessage -> Message
- ChatClientProtocol -> SupportsChatGetResponse

Also renamed internal WorkflowMessage (was Message in _runner_context) to avoid collision.

No backward compatibility aliases - this is a clean breaking change.

* [BREAKING] Rename Agent chat_client parameter to client

* Fix rebase issues: WorkflowMessage references and broken markdown links

* Fix formatting and lint issues from code quality checks

* Fix import ordering in workflow sample files

* fixed rebase

* Fix test failures: use WorkflowMessage and A2AMessage after ChatMessage→Message rename

- Replace Message(data=..., source_id=...) with WorkflowMessage(...) in workflow tests
- Fix isinstance check in A2A agent to use A2AMessage instead of Message
- Fix import in test_workflow_observability.py (Message→WorkflowMessage)

* Fix lint, fmt, and sample errors after ChatMessage→Message rename

- Auto-fix 70+ ruff lint issues across samples (ChatMessage→Message refs)
- Fix HostedVectorStoreContent→Content.from_hosted_vector_store in file search sample
- Fix _normalize_messages→normalize_messages in custom agent sample
- Fix context.terminate→raise MiddlewareTermination in middleware samples
- Fix with_update_hook→with_transform_hook in override middleware sample
- Add TOptions_co import back to custom_chat_client sample
- Add noqa for FastAPI File() default in chatkit sample
- Fix B023 loop variable capture in weather agent sample

* fix: update Agent constructor calls from chat_client to client in declaration-only tool tests

* fix: add register_cleanup to devui lazy-loading proxy and type stub

* fixed tests and updated new pieces

* fix agui typevar

* fix merge errors

* fix merge conflicts

* fiux merge

* Remove unused links

---------

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

python/packages/claude/agent_framework_claude/_agent.py

@@ -14,10 +14,10 @@ from agent_framework import (
     AgentResponseUpdate,
     AgentThread,
     BaseAgent,
-    ChatMessage,
     Content,
     ContextProvider,
     FunctionTool,
+    Message,
     ToolProtocol,
     get_logger,
     normalize_messages,
@@ -541,7 +541,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
         if "permission_mode" in options:
             await self._client.set_permission_mode(options["permission_mode"])
 
-    def _format_prompt(self, messages: list[ChatMessage] | None) -> str:
+    def _format_prompt(self, messages: list[Message] | None) -> str:
         """Format messages into a prompt string.
 
         Args:
@@ -557,7 +557,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
     @overload
     def run(
         self,
-        messages: str | ChatMessage | Sequence[str | ChatMessage] | None = None,
+        messages: str | Message | Sequence[str | Message] | None = None,
         *,
         stream: Literal[True],
         thread: AgentThread | None = None,
@@ -568,7 +568,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
     @overload
     async def run(
         self,
-        messages: str | ChatMessage | Sequence[str | ChatMessage] | None = None,
+        messages: str | Message | Sequence[str | Message] | None = None,
         *,
         stream: Literal[False] = ...,
         thread: AgentThread | None = None,
@@ -578,7 +578,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
 
     def run(
         self,
-        messages: str | ChatMessage | Sequence[str | ChatMessage] | None = None,
+        messages: str | Message | Sequence[str | Message] | None = None,
         *,
         stream: bool = False,
         thread: AgentThread | None = None,
@@ -608,7 +608,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
 
     async def _run_non_streaming(
         self,
-        messages: str | ChatMessage | Sequence[str | ChatMessage] | None = None,
+        messages: str | Message | Sequence[str | Message] | None = None,
         *,
         thread: AgentThread | None = None,
         options: OptionsT | MutableMapping[str, Any] | None = None,
@@ -622,7 +622,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
 
     async def _run_streaming(
         self,
-        messages: str | ChatMessage | Sequence[str | ChatMessage] | None = None,
+        messages: str | Message | Sequence[str | Message] | None = None,
         *,
         thread: AgentThread | None = None,
         options: OptionsT | MutableMapping[str, Any] | None = None,

python/packages/claude/tests/test_claude_agent.py

@@ -4,7 +4,7 @@ from typing import Any
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
-from agent_framework import AgentResponseUpdate, AgentThread, ChatMessage, Content, tool
+from agent_framework import AgentResponseUpdate, AgentThread, Content, Message, tool
 
 from agent_framework_claude import ClaudeAgent, ClaudeAgentOptions, ClaudeAgentSettings
 from agent_framework_claude._agent import TOOLS_MCP_SERVER_NAME
@@ -686,7 +686,7 @@ class TestFormatPrompt:
     def test_format_user_message(self) -> None:
         """Test formatting user message."""
         agent = ClaudeAgent()
-        msg = ChatMessage(
+        msg = Message(
             role="user",
             contents=[Content.from_text(text="Hello")],
         )
@@ -697,9 +697,9 @@ class TestFormatPrompt:
         """Test formatting multiple messages."""
         agent = ClaudeAgent()
         messages = [
-            ChatMessage(role="user", contents=[Content.from_text(text="Hi")]),
-            ChatMessage(role="assistant", contents=[Content.from_text(text="Hello!")]),
-            ChatMessage(role="user", contents=[Content.from_text(text="How are you?")]),
+            Message(role="user", contents=[Content.from_text(text="Hi")]),
+            Message(role="assistant", contents=[Content.from_text(text="Hello!")]),
+            Message(role="user", contents=[Content.from_text(text="How are you?")]),
         ]
         result = agent._format_prompt(messages)  # type: ignore[reportPrivateUsage]
         assert "Hi" in result