The following identifiers are reserved as keywords and must not be used for defining MDL names or types:
| AliasedModel | Select | evaluate | protected |
| CompilerProject | Static | false | quiet |
| End | break | for | return |
| Info | calc | if | scanner |
| Instance | call | initialize | set |
| Interface | compile | instantiate | to |
| LinkMap | construct | link | true |
| LoadObjectLibrary | continue | listModels | undef |
| Local | destruct | method | verbose |
| Model | do | of | while |
| NewModel | else | parser | |
| Parameter | errors | private |
These restrictions do not apply to MDL parameter literals or string values.