after property
After names a previous run's session, and starts this one from where that one stopped instead of from the repository's default. It is how a follow-up instruction — "now add tests for it" — builds on work already done rather than beginning again on a fresh clone. It sets the base and nothing else, so this run still writes its OWN branch. One run, one branch: a run that wrote back onto an earlier run's branch would break the rule the forge's ref policy is built on, and would leave two turns of work with one name to review. A caller who already knows the branch may pass Base directly; this exists because the branch is derived from a session id and nobody should have to know how. Base wins if both are given.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? after;