feat(feishu): display tool calls in code block messages

- Add special handling for tool hint messages (_tool_hint metadata)
- Send tool calls using Feishu's "code" message type with formatting
- Tool calls now appear as formatted code snippets in Feishu chat
- Add unit tests for the new functionality

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

nanobot/channels/feishu.py

@@ -822,6 +822,21 @@ class FeishuChannel(BaseChannel):
             receive_id_type = "chat_id" if msg.chat_id.startswith("oc_") else "open_id"
             loop = asyncio.get_running_loop()
 
+            # Handle tool hint messages as code blocks
+            if msg.metadata.get("_tool_hint"):
+                if msg.content and msg.content.strip():
+                    code_content = {
+                        "title": "Tool Call",
+                        "code": msg.content.strip(),
+                        "language": "text"
+                    }
+                    await loop.run_in_executor(
+                        None, self._send_message_sync,
+                        receive_id_type, msg.chat_id, "code",
+                        json.dumps(code_content, ensure_ascii=False),
+                    )
+                return
+
             for file_path in msg.media:
                 if not os.path.isfile(file_path):
                     logger.warning("Media file not found: {}", file_path)

tests/test_feishu_tool_hint_code_block.py

@@ -0,0 +1,110 @@
+"""Tests for FeishuChannel tool hint code block formatting."""
+
+import json
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from nanobot.bus.events import OutboundMessage
+from nanobot.channels.feishu import FeishuChannel
+
+
+@pytest.fixture
+def mock_feishu_channel():
+    """Create a FeishuChannel with mocked client."""
+    config = MagicMock()
+    config.app_id = "test_app_id"
+    config.app_secret = "test_app_secret"
+    config.encrypt_key = None
+    config.verification_token = None
+    bus = MagicMock()
+    channel = FeishuChannel(config, bus)
+    channel._client = MagicMock()  # Simulate initialized client
+    return channel
+
+
+def test_tool_hint_sends_code_message(mock_feishu_channel):
+    """Tool hint messages should be sent as code blocks."""
+    msg = OutboundMessage(
+        channel="feishu",
+        chat_id="oc_123456",
+        content='web_search("test query")',
+        metadata={"_tool_hint": True}
+    )
+
+    with patch.object(mock_feishu_channel, '_send_message_sync') as mock_send:
+        # Run send in async context
+        import asyncio
+        asyncio.run(mock_feishu_channel.send(msg))
+
+        # Verify code message was sent
+        assert mock_send.call_count == 1
+        call_args = mock_send.call_args[0]
+        receive_id_type, receive_id, msg_type, content = call_args
+
+        assert receive_id_type == "chat_id"
+        assert receive_id == "oc_123456"
+        assert msg_type == "code"
+
+        # Parse content to verify structure
+        content_dict = json.loads(content)
+        assert content_dict["title"] == "Tool Call"
+        assert content_dict["code"] == 'web_search("test query")'
+        assert content_dict["language"] == "text"
+
+
+def test_tool_hint_empty_content_does_not_send(mock_feishu_channel):
+    """Empty tool hint messages should not be sent."""
+    msg = OutboundMessage(
+        channel="feishu",
+        chat_id="oc_123456",
+        content="   ",  # whitespace only
+        metadata={"_tool_hint": True}
+    )
+
+    with patch.object(mock_feishu_channel, '_send_message_sync') as mock_send:
+        import asyncio
+        asyncio.run(mock_feishu_channel.send(msg))
+
+        # Should not send any message
+        mock_send.assert_not_called()
+
+
+def test_tool_hint_without_metadata_sends_as_normal(mock_feishu_channel):
+    """Regular messages without _tool_hint should use normal formatting."""
+    msg = OutboundMessage(
+        channel="feishu",
+        chat_id="oc_123456",
+        content="Hello, world!",
+        metadata={}
+    )
+
+    with patch.object(mock_feishu_channel, '_send_message_sync') as mock_send:
+        import asyncio
+        asyncio.run(mock_feishu_channel.send(msg))
+
+        # Should send as text message (detected format)
+        assert mock_send.call_count == 1
+        call_args = mock_send.call_args[0]
+        _, _, msg_type, content = call_args
+        assert msg_type == "text"
+        assert json.loads(content) == {"text": "Hello, world!"}
+
+
+def test_tool_hint_multiple_tools_in_one_message(mock_feishu_channel):
+    """Multiple tool calls should be in a single code block."""
+    msg = OutboundMessage(
+        channel="feishu",
+        chat_id="oc_123456",
+        content='web_search("query"), read_file("/path/to/file")',
+        metadata={"_tool_hint": True}
+    )
+
+    with patch.object(mock_feishu_channel, '_send_message_sync') as mock_send:
+        import asyncio
+        asyncio.run(mock_feishu_channel.send(msg))
+
+        call_args = mock_send.call_args[0]
+        content = json.loads(call_args[3])
+        assert content["code"] == 'web_search("query"), read_file("/path/to/file")'
+        assert "\n" not in content["code"]  # Single line as intended