diff --git a/agent/conversation_loop.py b/agent/conversation_loop.py
index bf2b306bc602e..38d6b2794c24b 100644
--- a/agent/conversation_loop.py
+++ b/agent/conversation_loop.py
@@ -1799,7 +1799,33 @@ def run_conversation(
             )
 
         api_messages = []
+        _interrupt_scaffold = (
+            "[This response was interrupted by a user correction.]"
+        )
         for idx, msg in enumerate(messages):
+            # Legacy ghost rows from the incomplete #73146 else branch: a
+            # hidden assistant placeholder whose content/api_content is the
+            # raw interrupt scaffold. Replaying that as an assistant message
+            # makes the model echo it and self-replicate (#81841). Drop them
+            # so pre-fix session history cannot keep poisoning new turns.
+            _ghost_content = msg.get("content")
+            _ghost_api = msg.get("api_content")
+            if (
+                msg.get("display_kind") == "hidden"
+                and msg.get("role") == "assistant"
+                and (
+                    (
+                        isinstance(_ghost_content, str)
+                        and _ghost_content.strip() == _interrupt_scaffold
+                    )
+                    or (
+                        isinstance(_ghost_api, str)
+                        and _ghost_api.strip() == _interrupt_scaffold
+                    )
+                )
+            ):
+                continue
+
             # Structural clone, NOT msg.copy(): every in-place transform
             # below (canonicalize/repair, surrogate + non-ASCII sanitizers,
             # cache decoration) must be unable to reach the persisted
diff --git a/tests/run_agent/test_run_agent.py b/tests/run_agent/test_run_agent.py
index a997214c5bf50..c63bd4e5a8a21 100644
--- a/tests/run_agent/test_run_agent.py
+++ b/tests/run_agent/test_run_agent.py
@@ -3649,6 +3649,56 @@ class TestRunConversation:
         )
         assert correction["content"] == "Use the corrected approach."
 
+    def test_legacy_interrupt_scaffold_ghost_dropped_from_api_replay(self, agent):
+        """Pre-#81841 hidden assistant rows with the interrupt scaffold must
+        not be replayed to the provider — that is what made the model echo
+        them into a self-replicating ghost loop."""
+        self._setup_agent(agent)
+        scaffold = "[This response was interrupted by a user correction.]"
+        history = [
+            {"role": "user", "content": "first"},
+            {
+                "role": "assistant",
+                "content": scaffold,
+                "api_content": scaffold,
+                "display_kind": "hidden",
+            },
+            {"role": "user", "content": "real follow-up"},
+            {"role": "assistant", "content": "ok"},
+        ]
+        requests = []
+
+        def _fake_api_call(api_kwargs):
+            requests.append(api_kwargs)
+            return _mock_response(content="done", finish_reason="stop")
+
+        with (
+            patch.object(agent, "_interruptible_api_call", side_effect=_fake_api_call),
+            patch.object(agent, "_persist_session"),
+            patch.object(agent, "_save_trajectory"),
+            patch.object(agent, "_cleanup_task_resources"),
+        ):
+            result = agent.run_conversation(
+                "next turn", conversation_history=history
+            )
+
+        assert result["completed"] is True
+        assert len(requests) == 1
+        replayed = requests[0]["messages"]
+        assert not any(
+            isinstance(m.get("content"), str) and m["content"].strip() == scaffold
+            for m in replayed
+            if m.get("role") == "assistant"
+        )
+        # Real history around the ghost still reaches the provider.
+        assert any(
+            m.get("role") == "user" and m.get("content") == "real follow-up"
+            for m in replayed
+        )
+        assert any(
+            m.get("role") == "assistant" and m.get("content") == "ok"
+            for m in replayed
+        )
 
     def test_nous_401_refreshes_after_remint_and_retries(self, agent):
         self._setup_agent(agent)