diff --git a/nanobot/utils/helpers.py b/nanobot/utils/helpers.py
index 3ce15ad6..ae008bec 100644
--- a/nanobot/utils/helpers.py
+++ b/nanobot/utils/helpers.py
@@ -63,8 +63,8 @@ def strip_think(text: str) -> str:
     # Stream chunks may end in the middle of a control tag. Strip only known
     # control-token prefixes at the very end.
     partial_control_tag = (
-        r"</?(?:t|th|thi|thin|think|tho|thou|thoug|though|thought)"
-        r"|<\|?(?:c|ch|cha|chan|chann|channe|channel|channel\|?)"
+        r"</?(?:t|th|thi|thin|think|tho|thou|thoug|though|thought)>?"
+        r"|<\|?(?:c|ch|cha|chan|chann|channe|channel)(?:\|?>?)?"
     )
     text = re.sub(rf"(?:{partial_control_tag})$", "", text)
     text = re.sub(r"^\s*<\|?$", "", text)
diff --git a/tests/agent/test_runner.py b/tests/agent/test_runner.py
index 79af0a67..10d25348 100644
--- a/tests/agent/test_runner.py
+++ b/tests/agent/test_runner.py
@@ -993,6 +993,27 @@ async def test_loop_stream_filter_hides_partial_trailing_think_prefix(tmp_path):
     assert deltas == ["Hello", " World"]
 
 
+@pytest.mark.asyncio
+async def test_loop_stream_filter_hides_complete_trailing_think_tag(tmp_path):
+    loop = _make_loop(tmp_path)
+    deltas: list[str] = []
+
+    async def chat_stream_with_retry(*, on_content_delta, **kwargs):
+        await on_content_delta("Hello <think>")
+        await on_content_delta("hidden</think>World")
+        return LLMResponse(content="Hello <think>hidden</think>World", tool_calls=[], usage={})
+
+    loop.provider.chat_stream_with_retry = chat_stream_with_retry
+
+    async def on_stream(delta: str) -> None:
+        deltas.append(delta)
+
+    final_content, _, _, _, _ = await loop._run_agent_loop([], on_stream=on_stream)
+
+    assert final_content == "Hello World"
+    assert deltas == ["Hello", " World"]
+
+
 @pytest.mark.asyncio
 async def test_loop_retries_think_only_final_response(tmp_path):
     loop = _make_loop(tmp_path)
diff --git a/tests/utils/test_strip_think.py b/tests/utils/test_strip_think.py
index 7adbe7bc..5db93e65 100644
--- a/tests/utils/test_strip_think.py
+++ b/tests/utils/test_strip_think.py
@@ -105,10 +105,12 @@ class TestStripThinkMalformedLeaks:
     def test_partial_trailing_think_tag_after_visible_text(self):
         assert strip_think("喷泉策略说明 <thin") == "喷泉策略说明"
         assert strip_think("answer <thought") == "answer"
+        assert strip_think("answer <think>") == "answer"
 
     def test_partial_trailing_channel_marker_after_visible_text(self):
         assert strip_think("喷泉策略说明 <|chan") == "喷泉策略说明"
         assert strip_think("answer <channel") == "answer"
+        assert strip_think("answer <|channel|>") == "answer"
 
 
 class TestStripThinkConservativePreserve: