LongText.acceptVariableAsPlaceholder welded a fact about the value to a
rendering choice: only a field also drawn as a textarea could say it is
interpolated. That left LLMDescriptor.model unable to declare it - the
capability worked, since the executors resolve the field as a template,
but nothing in the schema said so and nothing in the editor showed it.
@AcceptsVariablePlaceholder is that fact on its own. LongText keeps its
flag as the shorthand for the many prompt fields that are both, and the
new metadata is applied after it so that LongText writing the same key as
false cannot win: either annotation saying yes is enough.
The model field also gains a description, so the editor can say what an
empty value and a placeholder each do rather than leaving both to be
guessed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>