fix(feishu): prevent tool hint stacking and clean hints on stream_end

Three fixes for inline tool hints:

1. Consecutive tool hints now replace the previous one instead of
   stacking — the old suffix is stripped before appending the new one.

2. When _resuming flushes the buffer, any trailing tool hint suffix
   is removed so it doesn't persist into the next streaming segment.

3. When final _stream_end closes the card, tool hint suffix is
   cleaned from the text before the final card update.

Adds 3 regression tests covering all three scenarios.

Made-with: Cursor

nanobot/channels/feishu.py

@@ -1287,6 +1287,9 @@ class FeishuChannel(BaseChannel):
                 # next segment appends to the same card.
                 buf = self._stream_bufs.get(chat_id)
                 if buf and buf.card_id and buf.text:
+                    if buf.tool_hint_len > 0:
+                        buf.text = buf.text[:-buf.tool_hint_len]
+                        buf.tool_hint_len = 0
                     buf.sequence += 1
                     await loop.run_in_executor(
                         None, self._stream_update_text_sync, buf.card_id, buf.text, buf.sequence,
@@ -1296,6 +1299,9 @@ class FeishuChannel(BaseChannel):
             buf = self._stream_bufs.pop(chat_id, None)
             if not buf or not buf.text:
                 return
+            if buf.tool_hint_len > 0:
+                buf.text = buf.text[:-buf.tool_hint_len]
+                buf.tool_hint_len = 0
             if buf.card_id:
                 buf.sequence += 1
                 await loop.run_in_executor(
@@ -1376,6 +1382,8 @@ class FeishuChannel(BaseChannel):
                     return
                 buf = self._stream_bufs.get(msg.chat_id)
                 if buf and buf.card_id:
+                    if buf.tool_hint_len > 0:
+                        buf.text = buf.text[:-buf.tool_hint_len]
                     suffix = f"\n\n---\n🔧 {hint}"
                     buf.text += suffix
                     buf.tool_hint_len = len(suffix)

tests/channels/test_feishu_streaming.py

@@ -349,6 +349,70 @@ class TestToolHintInlineStreaming:
         assert "oc_chat1" not in ch._stream_bufs
         ch._client.im.v1.message.create.assert_called_once()
 
+    @pytest.mark.asyncio
+    async def test_consecutive_tool_hints_replace_previous(self):
+        """When multiple tool hints arrive consecutively, each replaces the previous one."""
+        ch = _make_channel()
+        ch._stream_bufs["oc_chat1"] = _FeishuStreamBuf(
+            text="Partial answer", card_id="card_1", sequence=2, last_edit=0.0,
+        )
+        ch._client.cardkit.v1.card_element.content.return_value = _mock_content_response()
+
+        msg1 = OutboundMessage(
+            channel="feishu", chat_id="oc_chat1",
+            content='$ cd /project', metadata={"_tool_hint": True},
+        )
+        await ch.send(msg1)
+
+        msg2 = OutboundMessage(
+            channel="feishu", chat_id="oc_chat1",
+            content='$ git status', metadata={"_tool_hint": True},
+        )
+        await ch.send(msg2)
+
+        buf = ch._stream_bufs["oc_chat1"]
+        assert buf.text.count("$ cd /project") == 0
+        assert buf.text.count("$ git status") == 1
+        assert buf.text.startswith("Partial answer")
+        assert buf.text.endswith("🔧 $ git status")
+
+    @pytest.mark.asyncio
+    async def test_tool_hint_stripped_on_resuming_flush(self):
+        """When _resuming flushes the buffer, tool hint suffix is cleaned."""
+        ch = _make_channel()
+        suffix = "\n\n---\n🔧 $ cd /project"
+        ch._stream_bufs["oc_chat1"] = _FeishuStreamBuf(
+            text="Partial answer" + suffix,
+            card_id="card_1", sequence=2, last_edit=0.0,
+            tool_hint_len=len(suffix),
+        )
+        ch._client.cardkit.v1.card_element.content.return_value = _mock_content_response()
+
+        await ch.send_delta("oc_chat1", "", metadata={"_stream_end": True, "_resuming": True})
+
+        buf = ch._stream_bufs["oc_chat1"]
+        assert buf.text == "Partial answer"
+        assert buf.tool_hint_len == 0
+
+    @pytest.mark.asyncio
+    async def test_tool_hint_stripped_on_final_stream_end(self):
+        """When final _stream_end closes the card, tool hint suffix is cleaned from text."""
+        ch = _make_channel()
+        suffix = "\n\n---\n🔧 web_fetch(\"url\")"
+        ch._stream_bufs["oc_chat1"] = _FeishuStreamBuf(
+            text="Final content" + suffix,
+            card_id="card_1", sequence=3, last_edit=0.0,
+            tool_hint_len=len(suffix),
+        )
+        ch._client.cardkit.v1.card_element.content.return_value = _mock_content_response()
+        ch._client.cardkit.v1.card.settings.return_value = _mock_content_response()
+
+        await ch.send_delta("oc_chat1", "", metadata={"_stream_end": True})
+
+        assert "oc_chat1" not in ch._stream_bufs
+        update_call = ch._client.cardkit.v1.card_element.content.call_args[0][0]
+        assert "🔧" not in update_call.body.content
+
 
 class TestSendMessageReturnsId:
     def test_returns_message_id_on_success(self):