feat(ai_client): Support external MCP tools and HITL approval

tests/test_external_mcp_hitl.py

@@ -0,0 +1,62 @@
+import asyncio
+import json
+import pytest
+from unittest.mock import MagicMock, patch, AsyncMock
+from src import ai_client
+from src import mcp_client
+from src import models
+
+@pytest.mark.asyncio
+async def test_external_mcp_hitl_approval():
+    # 1. Setup mock manager and server
+    mock_manager = mcp_client.ExternalMCPManager()
+    mock_server = AsyncMock()
+    mock_server.name = "test-server"
+    mock_server.tools = {"ext_tool": {"name": "ext_tool", "description": "desc"}}
+    mock_server.call_tool.return_value = "Success"
+    mock_manager.servers["test-server"] = mock_server
+    
+    with patch("src.mcp_client.get_external_mcp_manager", return_value=mock_manager):
+        # 2. Setup ai_client callbacks
+        mock_pre_tool = MagicMock(return_value="Approved")
+        ai_client.confirm_and_run_callback = mock_pre_tool
+        
+        # 3. Call _execute_single_tool_call_async
+        name = "ext_tool"
+        args = {"arg1": "val1"}
+        call_id = "call_123"
+        base_dir = "."
+        
+        # We need to pass the callback to the function
+        name, cid, out, orig_name = await ai_client._execute_single_tool_call_async(
+            name, args, call_id, base_dir, mock_pre_tool, None, 0
+        )
+        
+        # 4. Assertions
+        assert out == "Success"
+        mock_pre_tool.assert_called_once()
+        # Check description contains EXTERNAL MCP
+        call_args = mock_pre_tool.call_args[0]
+        assert "EXTERNAL MCP TOOL: ext_tool" in call_args[0]
+        assert "arg1: 'val1'" in call_args[0]
+
+@pytest.mark.asyncio
+async def test_external_mcp_hitl_rejection():
+    mock_manager = mcp_client.ExternalMCPManager()
+    mock_server = AsyncMock()
+    mock_server.name = "test-server"
+    mock_server.tools = {"ext_tool": {"name": "ext_tool"}}
+    mock_manager.servers["test-server"] = mock_server
+    
+    with patch("src.mcp_client.get_external_mcp_manager", return_value=mock_manager):
+        mock_pre_tool = MagicMock(return_value=None) # Rejection
+        
+        name = "ext_tool"
+        args = {"arg1": "val1"}
+        
+        name, cid, out, orig_name = await ai_client._execute_single_tool_call_async(
+            name, args, "id", ".", mock_pre_tool, None, 0
+        )
+        
+        assert out == "USER REJECTED: tool execution cancelled"
+        mock_server.call_tool.assert_not_called()