---
source: tests/rule_docs.rs
expression: render_rule_doc(rule.as_ref())
---
## `missing-required-argument`
Flag a command invoked with fewer `{…}` groups than the required arity in its curated built-in signature (ChkTeX warning 14, decided on the parse tree and signature database rather than line heuristics). TeX also accepts unbraced single-token arguments (`\frac12`), so the rule stays silent whenever a following token could still supply the missing argument and fires only at a hard boundary: the end of the enclosing group, math shell, or environment, an alignment `&`, a `\\` line break, a blank line, or the end of the file. Contexts where a bare command is deliberate are skipped -- macro-definition bodies (`\newcommand{\bold}{\textbf}`), arguments of unknown commands, standalone `{…}` scope groups, `\let`-style alias forms, and names the file itself redefines. Report-only: the missing argument's content is the author's to write, so no fix is correct by construction.
A fraction missing its denominator:
```tex
$\frac{1}$
```
```text
warning: missing-required-argument
--> example.tex:1:2
|
1 | $\frac{1}$
| ^^^^^ `\frac` is missing 1 of its 2 required arguments
```
A command left bare at the end of a group, with nothing to take:
```tex
\emph{see \textbf}
```
```text
warning: missing-required-argument
--> example.tex:1:11
|
1 | \emph{see \textbf}
| ^^^^^^^ `\textbf` is missing its required argument
```