A tool is a specialized instance of a stock tool. Tools appear in the Tool Palettes window and implement tool functionality. A tool can be defined either in the stock tool's COM component or in its own module. Its definition always references the stock tool's class ID for its basic definition. Specialized configuration occurs in the tool's properties.
The IAcadTool interface encapsulates a tool's functionality and provides access to its content. This interface is the primary means of communication between the framework and a tool's implementation. When this interface is passed to the framework via the IAcadStockTool::CreateTool() method, the framework uses it to query the tool's data and display properties. After the tool is loaded, the framework calls its IAcadTool::Execute() method when the user selects or drags the tool. The tool developer's implementation of this method executes the tool's functionality.