On a paper form, a blank required field started a conversation. The clerk noticed the gap, picked up the phone, asked what you meant. The asterisk marked where attention was needed, but the clerk supplied the judgment — deciding whether an answer was missing, wrong, or simply unclear.
HTML5's required attribute, finalized in 2014, kept the first check and quietly discarded the rest. Its constraint fires on exactly one condition: the field is empty. The violation is called valueMissing. Any non-empty string clears it. The institution's demand for completeness survived; its capacity to distinguish completeness from plausibility did not.
When an agent encounters a required field without a known answer, it infers one from the label and surrounding context. The form submits. The specification cannot distinguish a value that was known from one that was guessed. We automated the symbol of institutional diligence while stripping away the diligence itself — and now we're surprised that systems built to fill in blanks are very good at filling in blanks.
1970s Asterisks appear on mainframe data-entry screens to flag required fields. The convention's origin is undocumented.
Mid-20th c. Paper forms adopt the symbol with a footnote legend: * = required. Clerks catch blanks, call submitters, flag ambiguities.
1990s Web designers inherit the red asterisk. Enforcement is hand-coded JavaScript — no HTML standard names the concept.
2014 HTML5 adds the required attribute. Its full constraint: "There must be a value (if set)."
Now Agents fill required fields by inference. Research on agent hallucination distinguishes agents that recognize when a field can't be reliably filled from those that guess anyway.