Scope Fields In Frontmatter

Scoped instruction files must declare their scope boundary in frontmatter using scope:, globs:, or applies_to: fields. Without a declared scope, the file's targeting is ambiguous and the agent cannot determine which files the instructions apply to.

Antipatterns

• Describing scope in prose ("This rule applies to Python files") without a frontmatter field. The check looks for scope:, globs:, or applies_to: key-value declarations, not prose descriptions.
• Using a non-standard field name like targets: or files:. The pattern matches scope, globs, and applies_to specifically.
• Omitting scope fields entirely because the file is "obviously" scoped by its directory path. The rule requires explicit declaration regardless of directory placement.

Pass / Fail

Pass

---
globs: "src/**/*.py"
---
# Python Style

Use `ruff` for formatting.

Fail

---
title: Python Style
---
# Python Style

Use `ruff` for formatting Python files.

Threshold

The check is gated by file size: rules below 30 lines do not fire. Tiny rules consumed in one narrow context get little benefit from explicit scope fields, and the noise drowns out genuine missing-scope cases on load-bearing rules.

Override the threshold per project in .ails/config.yml:

rule_thresholds:
  CORE:S:0013:
    min_lines: 50

Setting min_lines: 0 removes the gate and restores fire-on-every-rule behavior.

Limitations

Checks for scope-related frontmatter fields (scope, globs, applies_to). Does not validate whether the declared scope is correct.