rfc2119

name	rfc2119
description	Enforce correct usage of RFC 2119 requirement level keywords (MUST, SHOULD, MAY, etc.) in documentation and specifications. You MUST load this skill when writing or reviewing standards, specifications, or when applying RFC 2119 terminology.
license	MIT

Skill: rfc2119

Enforce the standardized meaning of requirement level keywords as defined in BCP 14 (RFC 2119).

Core Principles

• Absolute Requirements: Use MUST, REQUIRED, or SHALL only for absolute requirements of the specification.
• Absolute Prohibitions: Use MUST NOT or SHALL NOT only for absolute prohibitions.
• Strong Recommendations: Use SHOULD or RECOMMENDED when valid reasons exist to ignore an item, but the full implications must be understood and weighed.
• Weak Prohibitions: Use SHOULD NOT or NOT RECOMMENDED when a behavior is acceptable or useful in specific circumstances, but implications must be weighed before implementation.
• Optional Features: Use MAY or OPTIONAL for truly optional items. Implementations must interoperate regardless of feature presence.
• Capitalization: ALWAYS capitalize these keywords when used in their RFC 2119 context.
• Sparseness: Use imperatives sparingly. Limit usage to requirements necessary for interoperation or to prevent harm.