The syntax for referencing substitution variables is: %<variable name>%. All text entry fields support replacement.
Note that for an entry substitution variable the syntax is @entry@.
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, Update Issues, or Create Subtask post functions.
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. But referencing custom fields by their id will allow the configuration to survive the renaming of a custom field.
Leave the Value field empty while defining the custom field(s) in your post function to set the respective custom field value to blank in the issue being created or updated.
In the issue being created or updated:
The ID value is copied for customfield_id.
The field value itself is copied for customfield_name.
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 parentheses following the substitution variable name. For example: %created(yyyy-MM-dd)% will result in replacement like 2013-05-28.