diff --git a/cli.py b/cli.py
index 3b555a288fa..70c30f00730 100644
--- a/cli.py
+++ b/cli.py
@@ -890,6 +890,10 @@ def _cleanup_all_browsers(*args, **kwargs):
 
 # Guard to prevent cleanup from running multiple times on exit
 _cleanup_done = False
+# One-shot CLI finalization runs before process cleanup so plugins can observe
+# the session boundary while the agent is still attached. If a signal lands in
+# that narrow window, atexit cleanup must not emit that session finalize again.
+_single_query_finalize_attempted_session_ids: set[str | None] = set()
 # Weak reference to the active AIAgent for memory provider shutdown at exit
 _active_agent_ref = None
 _deferred_agent_startup_done = False
@@ -989,11 +993,13 @@ def _run_cleanup(*, notify_session_finalize: bool = True):
     # Shut down memory provider (on_session_end + shutdown_all) at actual
     # session boundary — NOT per-turn inside run_conversation().
     if notify_session_finalize:
-        _notify_session_finalize(
-            session_id=_active_agent_ref.session_id if _active_agent_ref else None,
-            platform="cli",
-            reason="shutdown",
-        )
+        cleanup_session_id = _active_agent_ref.session_id if _active_agent_ref else None
+        if _should_emit_cleanup_session_finalize(cleanup_session_id):
+            _notify_session_finalize(
+                session_id=cleanup_session_id,
+                platform="cli",
+                reason="shutdown",
+            )
     try:
         if _active_agent_ref and hasattr(_active_agent_ref, 'shutdown_memory_provider'):
             # Forward the agent's own transcript so memory providers'
@@ -1011,6 +1017,14 @@ def _run_cleanup(*, notify_session_finalize: bool = True):
         pass
 
 
+def _should_emit_cleanup_session_finalize(session_id: str | None) -> bool:
+    if not _single_query_finalize_attempted_session_ids:
+        return True
+    if session_id is None:
+        return False
+    return session_id not in _single_query_finalize_attempted_session_ids
+
+
 def _notify_session_finalize(
     *,
     session_id: str | None,
@@ -1068,11 +1082,17 @@ def _emit_interrupted_session_end(cli, *, reason: str = "keyboard_interrupt") ->
 def _notify_single_query_session_finalize(cli, *, reason: str = "shutdown") -> None:
     agent = getattr(cli, "agent", None)
     session_id = getattr(agent, "session_id", None) or getattr(cli, "session_id", None)
-    _notify_session_finalize(
-        session_id=session_id,
-        platform=getattr(agent, "platform", None) or "cli",
-        reason=reason,
-    )
+    if session_id in _single_query_finalize_attempted_session_ids:
+        return
+
+    try:
+        _notify_session_finalize(
+            session_id=session_id,
+            platform=getattr(agent, "platform", None) or "cli",
+            reason=reason,
+        )
+    finally:
+        _single_query_finalize_attempted_session_ids.add(session_id)
 
 
 def _finalize_single_query(cli) -> None:
diff --git a/tests/cli/test_single_query_session_finalize.py b/tests/cli/test_single_query_session_finalize.py
index 37ad56ff7a8..20a75acd37b 100644
--- a/tests/cli/test_single_query_session_finalize.py
+++ b/tests/cli/test_single_query_session_finalize.py
@@ -5,6 +5,12 @@ import pytest
 import cli
 
 
+@pytest.fixture(autouse=True)
+def reset_single_query_finalize_state(monkeypatch):
+    monkeypatch.setattr(cli, "_single_query_finalize_attempted_session_ids", set())
+    monkeypatch.setattr(cli, "_cleanup_done", False)
+
+
 def test_finalize_single_query_runs_cleanup_without_reemitting_finalize_before_release(monkeypatch):
     calls = []
     fake_cli = SimpleNamespace(_release_active_session=lambda: calls.append(("release", {})))
@@ -70,6 +76,54 @@ def test_finalize_single_query_runs_cleanup_when_finalize_hook_fails(monkeypatch
     assert calls == ["finalize", "cleanup", "release"]
 
 
+def test_finalize_single_query_signal_window_does_not_reemit_during_atexit(monkeypatch):
+    calls = []
+    fake_agent = SimpleNamespace(session_id="agent-session", platform="cli")
+    fake_cli = SimpleNamespace(
+        agent=fake_agent,
+        session_id="cli-session",
+        _release_active_session=lambda: calls.append(("release", {})),
+    )
+
+    def invoke_hook(name, **kwargs):
+        calls.append((name, kwargs))
+
+    def interrupted_cleanup(**_kwargs):
+        raise KeyboardInterrupt()
+
+    expected_finalize = (
+        "on_session_finalize",
+        {
+            "session_id": "agent-session",
+            "platform": "cli",
+            "reason": "shutdown",
+        },
+    )
+
+    original_run_cleanup = cli._run_cleanup
+    monkeypatch.setattr("hermes_cli.plugins.invoke_hook", invoke_hook)
+    monkeypatch.setattr(cli, "_run_cleanup", interrupted_cleanup)
+
+    with pytest.raises(KeyboardInterrupt):
+        cli._finalize_single_query(fake_cli)
+
+    assert calls == [expected_finalize, ("release", {})]
+
+    # Simulate later atexit cleanup after the interrupted one-shot path. The
+    # active agent may already be unavailable by then.
+    monkeypatch.setattr(cli, "_run_cleanup", original_run_cleanup)
+    monkeypatch.setattr(cli, "_active_agent_ref", None)
+    monkeypatch.setattr(cli, "_reset_terminal_input_modes_on_exit", lambda: None)
+    monkeypatch.setattr(cli, "_cleanup_all_terminals", lambda: None)
+    monkeypatch.setattr(cli, "_cleanup_all_browsers", lambda: None)
+    monkeypatch.setattr("tools.mcp_tool.shutdown_mcp_servers", lambda: None)
+    monkeypatch.setattr("agent.auxiliary_client.shutdown_cached_clients", lambda: None)
+
+    cli._run_cleanup()
+
+    assert calls == [expected_finalize, ("release", {})]
+
+
 def test_notify_single_query_session_finalize_uses_agent_session(monkeypatch):
     calls = []
     fake_agent = SimpleNamespace(session_id="agent-session", platform="cli")