Built-in Rules

FSH Lint comes with a comprehensive set of 25+ built-in rules organized into categories:

Rule Categories

Blocking Rules (4 rules)

Rules that must pass before other rules can run. These validate critical requirements.

• Blocking Rules - Critical validation rules

Correctness (11 rules)

Rules that ensure FHIR specification compliance and prevent errors

• Correctness Rules

Style (2 rules)

Rules that enforce consistent naming and formatting patterns

• Style Rules

Suspicious (2 rules)

Rules that detect potentially problematic patterns in FSH code

• Suspicious Rules

Documentation (4 rules)

Rules that ensure proper resource metadata and documentation

• Documentation Rules

Rule Severity Levels

• Error - Must be fixed; prevents compilation or causes runtime issues
• Warning - Should be fixed; best practice violation or potential issue
• Info - Informational; suggestions for improvement
• Hint - Optional; minor style suggestions

Configuring Rules

See the Rule Configuration guide for details on:

• Enabling/disabling rules
• Changing rule severity
• Rule-specific options
• Creating custom rules

Rule Statistics

Total built-in rules: 25

By severity:

• Error: Most critical rules
• Warning: Best practice violations
• Info: Documentation suggestions