Fix MCPStreamableHTTPTool auth headers not being passed correctly (#146)

* Fix MCPStreamableHTTPTool auth headers not being passed correctly

* code review

* code review

* Add unit tests for httpx client configuration in MCP tool registration

Tests verify that:
- Authorization header is set on httpx.AsyncClient
- User-Agent header is set on httpx.AsyncClient
- MCP_HTTP_CLIENT_TIMEOUT_SECONDS constant (90s) is used
- MCPStreamableHTTPTool receives http_client param (not headers)
- httpx clients are tracked in _http_clients for cleanup
- cleanup() properly closes all httpx clients

These tests prevent regression to the bug where passing headers
directly to MCPStreamableHTTPTool was silently ignored.

* Add end-to-end httpx client lifecycle tests

New TestHttpxClientLifecycle class with 4 tests:
- test_full_client_lifecycle_single_server: verifies client created by
  add_tool_servers_to_agent() is properly closed by cleanup()
- test_full_client_lifecycle_multiple_servers: verifies all clients are
  tracked and cleaned up when multiple MCP servers are configured
- test_cleanup_idempotent_no_clients: verifies cleanup() is safe when
  no clients exist
- test_cleanup_called_twice_after_creating_clients: verifies calling
  cleanup() multiple times doesn't cause issues

These tests ensure connection/file-descriptor leaks are prevented by
verifying the full client lifecycle from creation to cleanup.

* Add httpx as runtime dependency for agentframework tooling extension

httpx is now used directly in mcp_tool_registration_service.py to create
AsyncClient instances with pre-configured headers. Without this explicit
dependency, consumers could hit ModuleNotFoundError if httpx isn't
available through transitive dependencies.

* Fix linting issues in MCP tool registration tests

- Remove unused httpx import
- Remove unused mock_mcp_tool variable assignments
- Sort imports properly
- Remove trailing whitespace from blank lines

* Apply ruff formatting to test file

---------

Co-authored-by: Josina Joy <josjoy@microsoft.com>

Author: Josina20

libraries/microsoft-agents-a365-tooling-extensions-agentframework/microsoft_agents_a365/tooling/extensions/agentframework/services/mcp_tool_registration_service.py

@@ -9,6 +9,7 @@
 from agent_framework import ChatAgent, ChatMessage, ChatMessageStoreProtocol, MCPStreamableHTTPTool
 from agent_framework.azure import AzureOpenAIChatClient
 from agent_framework.openai import OpenAIChatClient
+import httpx
 
 from microsoft_agents.hosting.core import Authorization, TurnContext
 
@@ -24,6 +25,10 @@
 )
 
 
+# Default timeout for MCP server HTTP requests (in seconds)
+MCP_HTTP_CLIENT_TIMEOUT_SECONDS = 90.0
+
+
 class McpToolRegistrationService:
     """
     Provides MCP tool registration services for Agent Framework agents.
@@ -46,6 +51,7 @@ def __init__(self, logger: Optional[logging.Logger] = None):
             logger=self._logger
         )
         self._connected_servers = []
+        self._http_clients: List[httpx.AsyncClient] = []
 
     async def add_tool_servers_to_agent(
         self,
@@ -114,11 +120,17 @@ async def add_tool_servers_to_agent(
                         self._orchestrator_name
                     )
 
-                    # Create and configure MCPStreamableHTTPTool
+                    # Create httpx client with auth headers configured
+                    http_client = httpx.AsyncClient(
+                        headers=headers, timeout=MCP_HTTP_CLIENT_TIMEOUT_SECONDS
+                    )
+                    self._http_clients.append(http_client)
+
+                    # Create and configure MCPStreamableHTTPTool with http_client
                     mcp_tools = MCPStreamableHTTPTool(
                         name=server_name,
                         url=config.url,
-                        headers=headers,
+                        http_client=http_client,
                         description=f"MCP tools from {server_name}",
                     )
 
@@ -339,12 +351,21 @@ async def send_chat_history_from_store(
     async def cleanup(self):
         """Clean up any resources used by the service."""
         try:
+            # Close MCP server connections
             for plugin in self._connected_servers:
                 try:
                     if hasattr(plugin, "close"):
                         await plugin.close()
                 except Exception as cleanup_ex:
-                    self._logger.debug(f"Error during cleanup: {cleanup_ex}")
+                    self._logger.debug(f"Error during plugin cleanup: {cleanup_ex}")
             self._connected_servers.clear()
+
+            # Close httpx clients to prevent connection/file descriptor leaks
+            for http_client in self._http_clients:
+                try:
+                    await http_client.aclose()
+                except Exception as client_ex:
+                    self._logger.debug(f"Error closing http client: {client_ex}")
+            self._http_clients.clear()
         except Exception as ex:
             self._logger.debug(f"Error during service cleanup: {ex}")

libraries/microsoft-agents-a365-tooling-extensions-agentframework/pyproject.toml

@@ -28,6 +28,7 @@ dependencies = [
     "agent-framework-azure-ai >= 1.0.0b251114",
     "azure-identity >= 1.12.0",
     "typing-extensions >= 4.0.0",
+    "httpx >= 0.27.0",
 ]
 
 [project.urls]