diff --git a/sdk/python/tests/app_server_harness.py b/sdk/python/tests/app_server_harness.py
index 1a80a39d63..7bc6469727 100644
--- a/sdk/python/tests/app_server_harness.py
+++ b/sdk/python/tests/app_server_harness.py
@@ -77,19 +77,11 @@ class MockSseResponse:
         return chunks
 
 
-@dataclass(frozen=True)
-class MockJsonResponse:
-    """One queued JSON response served by the mock Responses API."""
-
-    body: Json
-
-
 class MockResponsesServer:
     """Local HTTP server that records `/v1/responses` requests and returns SSE."""
 
     def __init__(self) -> None:
         self._responses: queue.Queue[MockSseResponse] = queue.Queue()
-        self._compact_responses: queue.Queue[MockJsonResponse] = queue.Queue()
         self._requests: list[CapturedResponsesRequest] = []
         self._requests_lock = threading.Lock()
         self._server = _ResponsesHttpServer(("127.0.0.1", 0), _ResponsesHandler, self)
@@ -144,21 +136,6 @@ class MockResponsesServer:
             )
         )
 
-    def enqueue_compaction_summary(self, summary: str) -> None:
-        """Queue a compact endpoint response with one synthetic compaction item."""
-        self._compact_responses.put(
-            MockJsonResponse(
-                body={
-                    "output": [
-                        {
-                            "type": "compaction",
-                            "encrypted_content": summary,
-                        }
-                    ]
-                }
-            )
-        )
-
     def requests(self) -> list[CapturedResponsesRequest]:
         """Return all recorded Responses API requests."""
         with self._requests_lock:
@@ -203,10 +180,6 @@ class MockResponsesServer:
         """Return the next queued SSE response or fail the HTTP request."""
         return self._responses.get_nowait()
 
-    def _next_compact_response(self) -> MockJsonResponse:
-        """Return the next queued compact JSON response or fail the HTTP request."""
-        return self._compact_responses.get_nowait()
-
 
 class AppServerHarness:
     """Test fixture that points a pinned runtime app-server at MockResponsesServer."""
@@ -303,22 +276,11 @@ class _ResponsesHandler(BaseHTTPRequestHandler):
         self.send_error(404, f"unexpected GET {self.path}")
 
     def do_POST(self) -> None:
-        """Serve queued responses for `/v1/responses` and compact requests."""
+        """Serve queued SSE responses for `/v1/responses` requests."""
         length = int(self.headers.get("content-length", "0"))
         body = self.rfile.read(length)
         self.server.mock._record_request(self, body)
 
-        if self.path.endswith("/v1/responses/compact") or self.path.endswith(
-            "/responses/compact"
-        ):
-            try:
-                response = self.server.mock._next_compact_response()
-            except queue.Empty:
-                self.send_error(500, "no queued compact response")
-                return
-            self._send_json(response.body)
-            return
-
         if not (self.path.endswith("/v1/responses") or self.path.endswith("/responses")):
             self.send_error(404, f"unexpected POST {self.path}")
             return
diff --git a/sdk/python/tests/test_mock_app_server_integration.py b/sdk/python/tests/test_mock_app_server_integration.py
index 1d50969230..1a241ec92f 100644
--- a/sdk/python/tests/test_mock_app_server_integration.py
+++ b/sdk/python/tests/test_mock_app_server_integration.py
@@ -581,11 +581,13 @@ def test_approval_modes_preserve_real_app_server_state_without_override(
 ) -> None:
     """Resume, fork, and next turn should inherit approval settings unless overridden."""
     with AppServerHarness(tmp_path) as harness:
+        harness.responses.enqueue_assistant_message("source seeded", response_id="turn-mode-0")
         harness.responses.enqueue_assistant_message("turn override", response_id="turn-mode-1")
         harness.responses.enqueue_assistant_message("turn inherited", response_id="turn-mode-2")
 
         with Codex(config=harness.app_server_config()) as codex:
             source = codex.thread_start(approval_mode=ApprovalMode.deny_all)
+            source_result = source.run("seed the source rollout")
             resumed = codex.thread_resume(source.id)
             forked = codex.thread_fork(source.id)
             explicit_fork = codex.thread_fork(
@@ -634,6 +636,7 @@ def test_approval_modes_preserve_real_app_server_state_without_override(
     assert {
         "policies": inherited_policies,
         "final_responses": [
+            source_result.final_response,
             first_result.final_response,
             second_result.final_response,
         ],
@@ -645,7 +648,7 @@ def test_approval_modes_preserve_real_app_server_state_without_override(
             "after_turn_override": AskForApprovalValue.never.value,
             "after_omitted_turn": AskForApprovalValue.never.value,
         },
-        "final_responses": ["turn override", "turn inherited"],
+        "final_responses": ["source seeded", "turn override", "turn inherited"],
     }
 
 
@@ -757,7 +760,10 @@ def test_models_and_compact_use_real_app_server_rpcs(tmp_path) -> None:
     """Model listing and compaction should go through real app-server methods."""
     with AppServerHarness(tmp_path) as harness:
         harness.responses.enqueue_assistant_message("history", response_id="compact-history")
-        harness.responses.enqueue_compaction_summary("compact summary")
+        harness.responses.enqueue_assistant_message(
+            "compact summary",
+            response_id="compact-summary",
+        )
 
         with Codex(config=harness.app_server_config()) as codex:
             models = codex.models(include_hidden=True)
@@ -781,7 +787,7 @@ def test_models_and_compact_use_real_app_server_rpcs(tmp_path) -> None:
         "models_payload_has_data": True,
         "run_final_response": "history",
         "compact_response": {},
-        "request_kinds": ["responses", "compact"],
+        "request_kinds": ["responses", "responses"],
     }