System Value sources provide access to special values passed in from the execution environment.


This system value source has several sub-sources, each providing different information.


Returns a map of environment variables. Access individual variables using an expression like:


Java/JVM system properties

Returns a map of Java system properties. Access individual variables using an expression like:


Many Java system properties are set automatically, such as java.version, shown above. Some are listed here. Custom system properties can be set from the Java command-line, as shown below. But note that these cannot be passed from the Muse CLI - only mentioned here for the case where Muse tasks are executed by your code running in a JVM.

java -Dcustom1=value1 -Dcustom2=value2 MyAppClass


Returns the current username (as provided by the OS to the JVM). Access using this expression:



Returns the hostname of the computer (as determined by the DefaultEnvironmentPropertiesProvider class - see it for details). Access using this expression:



Command-line options

Access command-line options by name.

Named options are passed through the Muse CLI like this:

muse -o param1=value1 -o param2=value2 run task1

Access the options like this:



Provide the unique ID assigned to the task execution.


Operating System

Provides the name of the operating system (Windows, macOS, Linux, unknown).


Project Location

Provides the location of the project storage.



Provides access to metadata about the task.