Address copilot comments

python/packages/foundry_hosting/agent_framework_foundry_hosting/_toolbox.py

@@ -4,7 +4,8 @@ from __future__ import annotations
 
 import logging
 import os
-from typing import TYPE_CHECKING
+from contextlib import _AsyncGeneratorContextManager  # pyright: ignore[reportPrivateUsage]
+from typing import TYPE_CHECKING, Any, override
 from urllib.parse import urlsplit
 
 import httpx
@@ -170,6 +171,9 @@ class FoundryToolbox(MCPStreamableHTTPTool):
             auth=_ToolboxAuth(credential, token_scope),
             timeout=timeout,
         )
+        self._credential = credential
+        self._token_scope = token_scope
+        self._timeout = timeout
 
         super().__init__(
             name=tool_name,
@@ -179,8 +183,22 @@ class FoundryToolbox(MCPStreamableHTTPTool):
             load_tools=load_tools,
         )
 
+    @override
+    def get_mcp_client(self) -> _AsyncGeneratorContextManager[Any, None]:
+        """Get an authenticated MCP HTTP client.
+
+        Recreates the underlying HTTP client if it was previously closed.
+        """
+        if self._httpx_client is None:
+            self._httpx_client = httpx.AsyncClient(
+                auth=_ToolboxAuth(self._credential, self._token_scope),
+                timeout=self._timeout,
+            )
+        return super().get_mcp_client()
+
+    @override
     async def close(self) -> None:
-        """Close the MCP session and the toolbox-owned HTTP client."""
+        """Close the MCP session and toolbox HTTP client while preserving credentials and timeout for reconnection."""
         try:
             await super().close()
         finally:

python/packages/foundry_hosting/tests/test_toolbox.py

@@ -1,4 +1,5 @@
 # Copyright (c) Microsoft. All rights reserved.
+# pyright: reportPrivateUsage=false
 
 """Unit tests for FoundryToolbox."""
 
@@ -229,3 +230,62 @@ async def test_skills_source_uses_connected_session(monkeypatch: pytest.MonkeyPa
 
     assert result == ["skill-a"]
     assert captured["client"] is sentinel_session
+
+
+class TestFoundryToolboxReconnection:
+    async def test_close_preserves_credential_for_reconnection(self) -> None:
+        """After close(), get_mcp_client() should recreate an authenticated client."""
+        cred = _FakeCredential("reconnect-token")
+        toolbox = FoundryToolbox(
+            cred,
+            url="https://h/toolboxes/recon/mcp",
+            timeout=60.0,
+        )
+
+        assert toolbox._credential is cred
+        assert toolbox._token_scope == "https://ai.azure.com/.default"
+        assert toolbox._timeout == 60.0
+
+        assert toolbox._httpx_client is not None
+        assert isinstance(toolbox._httpx_client.auth, _ToolboxAuth)
+        original_auth = toolbox._httpx_client.auth
+
+        client = toolbox._httpx_client
+        client.aclose = AsyncMock()
+        await toolbox.close()
+
+        client.aclose.assert_awaited_once()
+        assert toolbox._httpx_client is None
+
+        assert toolbox._credential is cred
+        assert toolbox._timeout == 60.0
+
+        ctx_manager = toolbox.get_mcp_client()
+        assert toolbox._httpx_client is not None
+        assert isinstance(toolbox._httpx_client.auth, _ToolboxAuth)
+
+        new_auth = toolbox._httpx_client.auth
+        assert new_auth is not original_auth
+        assert new_auth._credential is cred
+
+        assert hasattr(ctx_manager, "__aenter__")
+        assert hasattr(ctx_manager, "__aexit__")
+
+        await toolbox.close()
+
+    async def test_close_idempotent_with_reconnection(self) -> None:
+        """Multiple close() calls don't break reconnection."""
+        cred = _FakeCredential()
+        toolbox = FoundryToolbox(
+            cred,
+            url="https://h/toolboxes/idem/mcp",
+        )
+
+        await toolbox.close()
+        await toolbox.close()
+
+        toolbox.get_mcp_client()
+        assert toolbox._httpx_client is not None
+        assert isinstance(toolbox._httpx_client.auth, _ToolboxAuth)
+
+        await toolbox.close()