BatchParamKey

See https://www.ibm.com/docs/en/workload-automation/9.3.0?topic=zos-coding-variables-in-jcl to get details about limits for both keys and values: 8 for keys (variable names), 44 for values (variable values) In addition, keys will be only alphabetic characters and digits, without any space or special characters (dash, underscore, etc ...)

Parameter key: the first character must be alphabetic. Can be of up to 8 alphanumeric characters.