Shared Validation Rule

Use this skill when the request is to create or update a reusable rule in packages/shared/src/validation/rules.

Objective

• Create new reusable validation rules within packages/shared.
• Follow exactly the structural, semantic, and testing pattern already adopted in the project.
• Reuse packages/shared/src/validation/rule.utils.ts whenever it makes sense.
• Create robust, concise unit tests focused on the rule's observable contract.
• Ensure correct integration with the shared package exports.
• Deliver a simple, predictable, reusable, and maintainable rule.

Required inputs

Run the implementation only when these inputs are clear in the request or can be inferred with low risk: