The syntax for referencing substitution variables is: %<variable name>%. All text entry fields support replacement.
Several example substitution variables are listed on the post function screen as an aid when creating definitions. However, the table below contains a more complete and detailed list of substitution variables available as you work with the Create Issue or Create Sub-task post function.
Table: containing valid substitution variables and their descriptions.
Working with custom fields
Custom fields are identified by either name or id (e.g., customfield_12345). Referencing a custom field by its name is often easier to know what the value is referring to. Yet, by referencing custom fields by their id will allow the configuration to survive the renaming of a custom field.
Configured date format
For date substitution variables, the format of the replacement variable can be specified if the default format is not desirable. The format is specified by a Simple Date Format string enclosed in parenthesis following the substitution variable name. For example: %created(yyyy-MM-dd)% will result in replacement like 2013-05-28.