The command line of an Activity allows your application to customize how the engine will start, to open or not a model on startup, which script to load (if applicable) and which appbundle to load. This section of the documentation deep dive into this topic. Here is a typical command line attribute value, note it's passing the engine path, then the file to load on start, the appbundle to load and, last, the script to execute.
$(engine.path)\InventorCoreConsole.exe /i $(args[InventorDoc].path) /al $(appbundles[SomeApp].path) /s $(settings[script].path)
Design Automation service controls the engine and script path value, but your application will provide the actual start model (args.path) and the appbundle (appbundles.path) values. And those values may contain space or other chars, leading to an ambiguous command line. To avoid such a scenario, most command-line tools that require users (or developers) to pass values between quotes.
Starting October 1st, Design Automation will enforce the quotes for start model (args.path) and appbundle (appbundles.path) parameters.
As an example, here is an adjusted command line with quotes.
$(engine.path)\InventorCoreConsole.exe /i "$(args[InventorDoc].path)" /al "$(appbundles[SomeApp].path)" /s $(settings[script].path)
Need more samples?
Check more command line samples at the Learn Forge tutorial, Activity section.