diff --git a/tests/tools/test_mcp_tool_session_expired.py b/tests/tools/test_mcp_tool_session_expired.py
index 4533282e70..59601ba1c3 100644
--- a/tests/tools/test_mcp_tool_session_expired.py
+++ b/tests/tools/test_mcp_tool_session_expired.py
@@ -53,6 +53,17 @@ def test_is_session_expired_detects_session_terminated():
     assert _is_session_expired_error(RuntimeError("Session terminated")) is True
 
 
+def test_is_session_expired_detects_stale_pipe_and_closed_transport_variants():
+    """Stdio/AnyIO stale-pipe failures usually surface as closed-resource
+    or broken-pipe text, not an HTTP session-expired JSON-RPC error."""
+    from tools.mcp_tool import _is_session_expired_error
+    assert _is_session_expired_error(RuntimeError("ClosedResourceError")) is True
+    assert _is_session_expired_error(RuntimeError("closed resource in MCP child")) is True
+    assert _is_session_expired_error(RuntimeError("transport is closed")) is True
+    assert _is_session_expired_error(RuntimeError("Broken pipe while writing request")) is True
+    assert _is_session_expired_error(RuntimeError("End of file from MCP server")) is True
+
+
 def test_is_session_expired_is_case_insensitive():
     """Match uses lower-cased comparison so servers that emit the
     message in different cases (SDK formatter quirks) still trigger."""
diff --git a/tools/mcp_tool.py b/tools/mcp_tool.py
index b2e0ae802c..5c45f1c4f2 100644
--- a/tools/mcp_tool.py
+++ b/tools/mcp_tool.py
@@ -1739,6 +1739,12 @@ _SESSION_EXPIRED_MARKERS: tuple = (
     "session not found",
     "unknown session",
     "session terminated",
+    "closedresourceerror",
+    "closed resource",
+    "transport is closed",
+    "connection closed",
+    "broken pipe",
+    "end of file",
 )