Whether an entry is caller-filled at start/spawn — the only source that
reads initialFields. Every other source (query/literal/fieldRead, or
working memory) resolves itself at materialisation, so a $fields.<name>
read of it can never bind on any read surface that evaluates a
start.filter. The deploy read-check keys on this.
Whether an entry is caller-filled at start/spawn — the only source that reads
initialFields. Every other source (query/literal/fieldRead, or working memory) resolves itself at materialisation, so a$fields.<name>read of it can never bind on any read surface that evaluates astart.filter. The deploy read-check keys on this.