Plug-in item names are used to name callback functions, so these names must be valid identifiers in your chosen programming language. The general rules for naming plug-in items are as follows:
In JScript, Python, C#, C++, the first character may also be an underscore (_).
Subsequent characters can be letters, numbers or underscore (_) characters.
Plug-in Names vs. Plug-in Item Names
In some cases you may be able to use a plug-in name that begins with a number if you use a different plug-in item name. For example, a company called 123GO may want to use their name to prefix their plug-ins for branding purposes. In this case they could create a plug-in called 123GO_PolyFix but the command must be called PolyFix or some other name beginning with a letter (or an underscore if the implementation language allows it).
Each wizard manages the relationship between the plug-in name and the plug-in item name slightly differently. Specific information is available on each wizard's help page.
Naming Conventions for Custom Parameters
Parameters added to custom properties must follow the same naming convention as plug-in items, because parameter names are also used in callback function names. For example, CCmdWizard_ScriptingName_OnChanged is the OnChanged callback for the ScriptingName parameter of the CCmdWizard property.