Principle Classification Model

The catalogue uses explicit classifications because lists of “best practices” often mix unlike concepts.

Classification	Meaning	Normative role
principle	General design rule expressing a desired relationship or property.	Usually context-sensitive and interpreted by a Core Skill.
heuristic	Useful default that may be overridden by evidence.	SHOULD-level guidance, rarely MUST.
technique	A concrete implementation mechanism.	Selected only when it realizes an active policy.
method	A structured way of working or specifying behavior.	Optional unless a profile or user requires it.
development-method	A development workflow such as TDD.	Never universal by default.
development-cycle	A repeated sequence inside a method.	Active only with its parent method or explicit selection.
architecture-pattern	A recurring structural arrangement.	Requires architectural justification.
architecture-style	A broader system organization.	MUST NOT be imposed on small tasks without authority.
architecture-rule	A directional or boundary rule from an architecture family.	MAY be used without adopting the entire family.
system-property	A property such as idempotency or eventual consistency.	Required when the system’s semantics demand it.
design-property	A local or systemic quality such as immutability.	Applied selectively according to costs.
security-principle	A rule governing authority or trust.	MAY become mandatory under a security modifier.
testing-principle	A rule about what tests protect.	Interpreted through testing strategy.
testing-pattern	A test-structure convention.	Optional structure, not a correctness guarantee.
testing-heuristic	A default for test scope or organization.	MUST NOT be reduced to a numeric rule.
testing-strategy	A distribution or portfolio of test types.	Chosen according to architecture and risk.
versioning-method	A convention for communicating evolution.	Requires a defined public API.
evolution-principle	Guidance for changing public or shared systems.	Stronger when consumers cannot update atomically.
organizational-principle	Guidance for code organization and ownership.	Applied at module or repository scale.
change-principle	Guidance for safe incremental modification.	Bounded by task scope and architecture authority.
law	An empirical or rhetorical observation about engineering systems.	Used as a review lens, never as a direct command.
design-philosophy	A broad stance on trade-offs and adoption.	Requires translation into specific decisions.
process-model	A sequence for implementation and improvement.	Adapted to known constraints.
umbrella-concept	A label that groups multiple practices.	Cannot be used as standalone justification.

A Core Skill MUST preserve the classification of its entries. It MUST NOT turn every heuristic into a mandatory rule or every law into an implementation instruction.