fix(gateway): reduce false duplicate-send alarms

gateway/run_turn.py

@@ -3633,9 +3633,18 @@ async def _run_agent_mark_streamed_delivery(self, response: Any, turn_ctx: TurnC
                     ok=("Edited streamed message %s for session %s to include plugin-transformed content.", _sc.message_id, _sk),
                     fail_result=None, fail_exc="Failed to edit streamed message for session %s: %s",
                 )
+        elif _sc is not None and not (_streamed or _previewed or _content_delivered):
+            # No stream delivery signal was set, so the normal final send is the only answer delivery.
+            # A consumer's mere existence cannot duplicate a reply and must not raise a delivery alarm.
+            logger.info(
+                "Stream consumer completed without user-visible final delivery for session %s: "
+                "normal final send required (streamed=%s previewed=%s content_delivered=%s "
+                "transformed=%s final_len=%d).",
+                _sk, _streamed, _previewed, _content_delivered, _transformed, len(_final),
+            )
         elif _sc is not None:
-            # DUPLICATE-RISK DIAGNOSTIC: a stream consumer existed but suppression did NOT fire; log the
-            # decision inputs ("signal never set" vs "ack-pending race").
+            # A delivery signal existed but could not prove the complete final was rendered. Keep this
+            # as a warning for the genuine acknowledgement/mismatch diagnostic family.
             logger.warning(
                 "Normal final-send NOT suppressed despite active stream consumer for session %s: "
                 "streamed=%s previewed=%s content_delivered=%s transformed=%s final_len=%d — "

tests/gateway/test_suppression_contract_matrix.py

@@ -26,11 +26,14 @@
 """
 
 import asyncio
+import logging
+from types import SimpleNamespace
 
 import pytest
 
 from gateway.config import Platform, PlatformConfig
 from gateway.platforms.base import BasePlatformAdapter, SendResult
+from gateway.session import SessionSource
 from gateway.stream_consumer import GatewayStreamConsumer, StreamConsumerConfig
 
 CURSOR = " ▉"
@@ -232,6 +235,38 @@ async def test_suppression_requires_the_complete_answer_on_the_wire(
         )
 
 
+@pytest.mark.asyncio
+async def test_no_delivery_signal_is_not_reported_as_a_duplicate_risk(caplog):
+    """A consumer that delivered no final content requires the normal final send.
+
+    Its existence alone cannot produce a duplicate: both delivery signals are
+    false. The diagnostic should retain that fact without raising a duplicate
+    alert for the health-check monitor.
+    """
+    from gateway.run import GatewayRunner
+
+    consumer = SimpleNamespace(
+        final_response_sent=False,
+        final_content_delivered=False,
+        delivered_final_matches=lambda final_text: False,
+    )
+    turn_ctx = SimpleNamespace(
+        stream_consumer_holder=[consumer],
+        source=SessionSource(platform=Platform.TELEGRAM, chat_id="chat-1"),
+        session_key="agent:main:telegram:dm:chat-1",
+    )
+    response = {"final_response": "Complete final answer."}
+
+    with caplog.at_level(logging.INFO, logger="gateway.run"):
+        await GatewayRunner._run_agent_mark_streamed_delivery(
+            object.__new__(GatewayRunner), response, turn_ctx
+        )
+
+    assert response.get("already_sent") is not True
+    assert "possible duplicate send" not in caplog.text
+    assert "normal final send required" in caplog.text
+
+
 @pytest.mark.parametrize(
     "edit_behaviour,send_behaviour,prefers_fresh_final,interrupt",
     list(_scenarios(lying_edits=True)),