# HARN-FMT-003 — formatter normalized trailing comma layout
**Category:** Formatter (FMT)
**Variant:** `Code::FormatterTrailingComma` (formatter trailing comma)
## What it means
The formatter could not produce a canonical layout for this source — either
because parsing failed first, or because the existing layout drifts from the
canonical form.
Specifically: formatter normalized trailing comma layout.
## How to fix
- Run `harn fmt` to bring the file to canonical form, or fix the parse error blocking the formatter.
## Stability
This code is stable. Its identifier, category, and meaning will not change
without a deprecation cycle. Cross-language tooling and IDE integrations can
dispatch on it directly.