Python: fix(foundry-hosting): root hosted checkpoints under durable home dire…

python/packages/foundry_hosting/agent_framework_foundry_hosting/_responses.py

@@ -391,6 +391,27 @@ class ResponsesHostServer(ResponsesAgentServerHost):
     CHECKPOINT_STORAGE_PATH = "/.checkpoints"
     FUNCTION_APPROVAL_STORAGE_PATH = "/.function_approvals/approval_requests.json"
 
+    @staticmethod
+    def _resolve_checkpoint_root(is_hosted: bool) -> str:
+        """Resolve checkpoint storage path.
+
+        Hosted: $HOME/.checkpoints (or /home/session/.checkpoints).
+        Local: {cwd}/.checkpoints.
+        """
+        if not is_hosted:
+            return os.path.join(os.getcwd(), ".checkpoints")
+
+        home = os.environ.get("HOME", "").strip()
+        if home and home != "/":
+            try:
+                resolved = Path(home).resolve()
+                if str(resolved) != str(resolved.root):
+                    return str(resolved / ".checkpoints")
+            except (OSError, ValueError):
+                pass
+
+        return "/home/session/.checkpoints"
+
     def __init__(
         self,
         agent: SupportsAgentRun,
@@ -439,11 +460,7 @@ def __init__(
                     "There should not be a checkpoint storage already present in the workflow agent. "
                     "The hosting infrastructure will manage checkpoints instead."
                 )
-            self._checkpoint_storage_path = (
-                self.CHECKPOINT_STORAGE_PATH
-                if self.config.is_hosted
-                else os.path.join(os.getcwd(), self.CHECKPOINT_STORAGE_PATH.lstrip("/"))
-            )
+            self._checkpoint_storage_path = self._resolve_checkpoint_root(self.config.is_hosted)
             self._is_workflow_agent = True
 
         self._agent = agent

python/packages/foundry_hosting/tests/test_responses.py

@@ -11,9 +11,11 @@
 from __future__ import annotations
 
 import json
+import os
 import uuid
 from collections.abc import AsyncIterator, Awaitable, Callable, Sequence
 from dataclasses import dataclass
+from pathlib import Path
 from typing import Literal, overload
 from unittest.mock import AsyncMock, MagicMock, patch
 
@@ -4317,4 +4319,99 @@ async def test_round_trip_approval_response_rejected(self) -> None:
         assert approval_responses[0].approved is False  # type: ignore[attr-defined]
 
 
+@pytest.mark.filterwarnings("ignore::DeprecationWarning")
+class TestCheckpointStoragePath:
+    """
+    In hosted mode, WorkflowAgent checkpoints must be stored under
+    $HOME/.checkpoints (durable across compute recreation), not
+    /.checkpoints (ephemeral root path that is wiped on idle).
+    """
+
+    @staticmethod
+    def _make_mock_workflow_agent() -> MagicMock:
+        """Create a mock WorkflowAgent for path-only tests."""
+        mock_workflow = MagicMock()
+        mock_workflow._runner_context.has_checkpointing.return_value = False
+        mock_workflow.name = "test-checkpoint-path"
+
+        mock_agent = MagicMock(spec=WorkflowAgent)
+        mock_agent.workflow = mock_workflow
+        mock_agent.context_providers = []
+
+        return mock_agent
+
+    def test_local_checkpoint_path_uses_cwd(self) -> None:
+        """In local mode, checkpoints should be under cwd, NOT root `/`."""
+        mock_agent = self._make_mock_workflow_agent()
+        _original_isinstance = isinstance
+
+        def _patched_isinstance(obj: Any, cls: Any) -> bool:
+            if cls is WorkflowAgent:
+                return True
+            return _original_isinstance(obj, cls)
+
+        with patch(
+            "agent_framework_foundry_hosting._responses.isinstance",
+            side_effect=_patched_isinstance,
+        ):
+            server = _make_server(mock_agent)
+
+        assert server._checkpoint_storage_path == os.path.join(os.getcwd(), ".checkpoints")
+
+    def test_hosted_checkpoint_path_uses_home(self, monkeypatch: pytest.MonkeyPatch) -> None:
+        """In hosted mode with valid HOME, checkpoints must be under $HOME/.checkpoints."""
+        monkeypatch.setenv("FOUNDRY_HOSTING_ENVIRONMENT", "true")
+        monkeypatch.setenv("HOME", "/home/testuser")
+        mock_agent = self._make_mock_workflow_agent()
+        _original_isinstance = isinstance
+
+        def _patched_isinstance(obj: Any, cls: Any) -> bool:
+            if cls is WorkflowAgent:
+                return True
+            return _original_isinstance(obj, cls)
+
+        with patch(
+            "agent_framework_foundry_hosting._responses.isinstance",
+            side_effect=_patched_isinstance,
+        ):
+            server = ResponsesHostServer(mock_agent, store=InMemoryResponseProvider())
+
+        checkpoint_path  = server._checkpoint_storage_path
+        assert checkpoint_path is not None
+        actual_normalized = checkpoint_path.replace("\\", "/")
+        assert actual_normalized.endswith("/home/testuser/.checkpoints")
+        assert not actual_normalized.startswith("/.checkpoints")
+
+    def test_hosted_without_home_env_uses_default_session_dir(self, monkeypatch: pytest.MonkeyPatch) -> None:
+        """When HOME is unset in hosted mode, fall back to /home/session/.checkpoints."""
+        monkeypatch.setenv("FOUNDRY_HOSTING_ENVIRONMENT", "true")
+        monkeypatch.delenv("HOME", raising=False)
+        mock_agent = self._make_mock_workflow_agent()
+
+        with patch(
+            "agent_framework_foundry_hosting._responses.isinstance",
+            side_effect=lambda o, c: c is WorkflowAgent or isinstance(o, c),
+        ):
+            server = ResponsesHostServer(mock_agent, store=InMemoryResponseProvider())
+
+        assert server._checkpoint_storage_path == "/home/session/.checkpoints"
+
+    @pytest.mark.parametrize("bad_home", ["/", "", "   "])
+    def test_hosted_with_unusable_home_falls_back_to_default(
+        self, monkeypatch: pytest.MonkeyPatch, bad_home: str
+    ) -> None:
+        """Filesystem-root or empty HOME must NOT produce /.checkpoints."""
+        monkeypatch.setenv("FOUNDRY_HOSTING_ENVIRONMENT", "true")
+        monkeypatch.setenv("HOME", bad_home)
+        mock_agent = self._make_mock_workflow_agent()
+
+        with patch(
+            "agent_framework_foundry_hosting._responses.isinstance",
+            side_effect=lambda o, c: c is WorkflowAgent or isinstance(o, c),
+        ):
+            server = ResponsesHostServer(mock_agent, store=InMemoryResponseProvider())
+
+        assert server._checkpoint_storage_path == "/home/session/.checkpoints"
+        assert server._checkpoint_storage_path != "/.checkpoints"
+
 # endregion

python/packages/foundry_hosting/tests/test_responses_int.py

@@ -259,6 +259,14 @@ async def test_input_image_url(self, server: ResponsesHostServer) -> None:
         output_text = output_messages[0]["content"][0]["text"].lower()
         assert "cat" in output_text
 
+    @pytest.mark.xfail(
+        reason=(
+            "Foundry Responses API rejects inline base64 data URIs in image_url with "
+            "'invalid_payload: ... is not a valid absolute URI'. It requires an absolute "
+            "http(s) URI or an uploaded file_id. Re-enable if Foundry adds data-URI support."
+        ),
+        strict=False,
+    )
     @pytest.mark.flaky
     @pytest.mark.integration
     @skip_if_foundry_hosting_integration_tests_disabled