Activation Contract
Load when picking a design pattern for a concrete problem, reviewing code for SOLID violations, choosing between Clean/Hexagonal/Screaming Architecture, structuring UI with atomic design or container/presentational, or when a pattern is proposed with no forcing problem behind it.
Hard Rules
- Name the forcing problem before naming a pattern: what varies, what must stay closed to change.
- Indirection that removes no duplication and isolates no real axis of change is over-engineering — reject it.
- Apply a SOLID principle only when its violation causes a real symptom (rigidity, fragility, immobility) — not as a checklist.
- Clean/Hexagonal Architecture: dependencies point inward only; domain/use-case code imports nothing from framework, DB, or transport.
- Screaming Architecture: top-level folders name the business domain (
billing/), never the framework (controllers/).
- Atomic design layers (atoms → molecules → organisms → templates → pages) compose upward only.
- Container/presentational: presentational components take only props and render; containers own state, side effects, and data fetching.
Decision Gates
| Symptom |
Pattern family |
Rule prefix |
| Object creation scattered or duplicated |
Creational (Factory Method, Builder, Singleton, Prototype, Abstract Factory) |
rules/creational-* |
| Incompatible interfaces or subsystems must cooperate |
Structural (Adapter, Facade, Decorator, Composite, Bridge, Proxy, Flyweight) |
rules/structural-* |
| Behavior or algorithm must vary at runtime |
Behavioral (Strategy, Observer, Command, State, +6 more) |
rules/behavioral-* |
| Business logic coupled to framework/DB/UI, folders mirror the framework, UI markup duplicated across granularities, or a component mixes fetching with rendering |
Architecture style (Clean/Hexagonal, Screaming, Atomic Design, Container/Presentational) |
rules/architecture-* |
Execution Steps
- State the forcing problem in one sentence: what changes, what must not break.
- Match it in the Decision Gate table, then read the matching
rules/<prefix>-*.md files for intent, problem/solution, and when to avoid.
- Propose the smallest pattern that solves it — reject heavier variants applied "for the future."
- If code already violates the pattern's shape, cite the violation (file/line) before the fix.
- Confirm the pattern doesn't cross an existing architecture boundary (e.g., a Strategy inside a Hexagonal domain layer must not import infra).
Output Contract
Report: forcing problem, pattern(s) proposed, one-sentence trade-off, file/line of any violation found.
References
One rule file per pattern under rules/, named <category>-<pattern-slug>.md:
rules/creational-*.md (5) and rules/structural-*.md (7) and rules/behavioral-*.md (10) — the 22 GoF patterns, matching refactoring.guru's catalog order, each with intent, problem/solution, when to avoid, and its source URL.rules/architecture-*.md (4) — Clean/Hexagonal Architecture, Screaming Architecture, Atomic Design, Container/Presentational (not from refactoring.guru).
1---2name: design-patterns3description: Trigger: design pattern, SOLID, Clean Architecture, Hexagonal Architecture, Screaming Architecture, atomic design, container-presentational, over-engineering, patron de diseno, refactor for maintainability. Picks the pattern the problem forces.4license: MIT5---67## Activation Contract89Load when picking a design pattern for a concrete problem, reviewing code for SOLID violations, choosing between Clean/Hexagonal/Screaming Architecture, structuring UI with atomic design or container/presentational, or when a pattern is proposed with no forcing problem behind it.1011## Hard Rules1213- Name the forcing problem before naming a pattern: what varies, what must stay closed to change.14- Indirection that removes no duplication and isolates no real axis of change is over-engineering — reject it.15- Apply a SOLID principle only when its violation causes a real symptom (rigidity, fragility, immobility) — not as a checklist.16- Clean/Hexagonal Architecture: dependencies point inward only; domain/use-case code imports nothing from framework, DB, or transport.17- Screaming Architecture: top-level folders name the business domain (`billing/`), never the framework (`controllers/`).18- Atomic design layers (atoms → molecules → organisms → templates → pages) compose upward only.19- Container/presentational: presentational components take only props and render; containers own state, side effects, and data fetching.2021## Decision Gates2223| Symptom | Pattern family | Rule prefix |24|---|---|---|25| Object creation scattered or duplicated | Creational (Factory Method, Builder, Singleton, Prototype, Abstract Factory) | `rules/creational-*` |26| Incompatible interfaces or subsystems must cooperate | Structural (Adapter, Facade, Decorator, Composite, Bridge, Proxy, Flyweight) | `rules/structural-*` |27| Behavior or algorithm must vary at runtime | Behavioral (Strategy, Observer, Command, State, +6 more) | `rules/behavioral-*` |28| Business logic coupled to framework/DB/UI, folders mirror the framework, UI markup duplicated across granularities, or a component mixes fetching with rendering | Architecture style (Clean/Hexagonal, Screaming, Atomic Design, Container/Presentational) | `rules/architecture-*` |2930## Execution Steps31321. State the forcing problem in one sentence: what changes, what must not break.332. Match it in the Decision Gate table, then read the matching `rules/<prefix>-*.md` files for intent, problem/solution, and when to avoid.343. Propose the smallest pattern that solves it — reject heavier variants applied "for the future."354. If code already violates the pattern's shape, cite the violation (file/line) before the fix.365. Confirm the pattern doesn't cross an existing architecture boundary (e.g., a Strategy inside a Hexagonal domain layer must not import infra).3738## Output Contract3940Report: forcing problem, pattern(s) proposed, one-sentence trade-off, file/line of any violation found.4142## References4344One rule file per pattern under `rules/`, named `<category>-<pattern-slug>.md`:4546- `rules/creational-*.md` (5) and `rules/structural-*.md` (7) and `rules/behavioral-*.md` (10) — the 22 GoF patterns, matching refactoring.guru's catalog order, each with intent, problem/solution, when to avoid, and its source URL.47- `rules/architecture-*.md` (4) — Clean/Hexagonal Architecture, Screaming Architecture, Atomic Design, Container/Presentational (not from refactoring.guru).
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