Skill Claude CodeCodex
Review a system design for security and reliability tradeoffs before implementation begins. Use when: evaluating an architecture proposal or design document and need to identify where security and reliability requirements conflict with feature or cost requirements; auditing a proposed design to determine whether…
Skill Claude CodeCodex
Select and implement a layered security testing strategy for a codebase: design unit tests for security properties (boundary conditions, negative inputs, access control invariants), set up integration testing with non-production seed data (avoiding the production data copy anti-pattern), choose and configure dynamic…
Plugin Claude Code
15 skills for GoF design pattern selection and implementation, extracted from Design Patterns by Gamma, Helm, Johnson, Vlissides.
Skill Claude CodeCodex
Implement the Abstract Factory pattern to create families of related objects without specifying their concrete classes. Use when a system must be independent of how its products are created, when it must work with multiple product families, when products are designed to be used together and you need to enforce that…
Skill Claude CodeCodex
Choose the right behavioral design pattern from the 11 GoF behavioral patterns. Use when someone asks "how do I make this algorithm swappable?", "should I use Strategy or State?", "how do I decouple senders from receivers?", "what's the difference between Observer and Mediator?", "how do I add undo/redo?", "how do I…
Skill Claude CodeCodex
Implement the Bridge pattern to decouple an abstraction from its implementation so both can vary independently. Use when you want to avoid a permanent binding between abstraction and implementation, when both abstractions and implementations should be extensible by subclassing, when implementation changes should not…
Skill Claude CodeCodex
Implement the Command pattern to encapsulate requests as objects, enabling parameterized operations, queuing, logging, and undo/redo. Use when you need to decouple UI elements from operations, implement multi-level undo with command history, support macro recording, queue or schedule requests, or log operations for…
Skill Claude CodeCodex
Implement the Composite pattern to compose objects into tree structures representing part-whole hierarchies, letting clients treat individual objects and compositions uniformly. Use when building file systems, UI component trees, organization charts, document structures, or any recursive containment hierarchy.…
Skill Claude CodeCodex
Choose the right creational design pattern (Abstract Factory, Builder, Factory Method, Prototype, or Singleton) for an object creation problem. Use when someone asks "which factory pattern should I use?", "should I use Abstract Factory or Factory Method?", "how do I create objects without specifying the concrete…
Skill Claude CodeCodex
Implement the Decorator pattern to attach additional responsibilities to objects dynamically, providing a flexible alternative to subclassing. Use when you need to add behaviors like logging, caching, validation, authentication, compression, or UI embellishments without creating a subclass for every combination.…
Skill Claude CodeCodex
Select the right GoF design pattern for a specific object-oriented design problem. Use when facing any of these situations: object creation inflexibility (too many concrete class references), tight coupling between classes, subclass explosion from trying to extend behavior, inability to modify a class you don't own…
Skill Claude CodeCodex
Design a system using multiple coordinated design patterns, moving beyond single-pattern application to pattern composition. Use when facing a complex system with multiple design problems — object creation inflexibility, structural rigidity, and behavioral coupling occurring simultaneously. Guides through the Lexi…
Skill Claude CodeCodex
Implement the Observer pattern to establish one-to-many dependencies where changing one object automatically notifies and updates all dependents. Use when a spreadsheet model needs to update multiple chart views, when UI components must react to data changes, when event systems need publish-subscribe, or when you need…
Skill Claude CodeCodex
Evaluate object-oriented designs against the two foundational GoF principles: 'Program to an interface, not an implementation' and 'Favor object composition over class inheritance.' Use when reviewing class hierarchies, assessing reuse strategies, or deciding between inheritance and composition for a specific design…
Skill Claude CodeCodex
Detect common OO design smells in a codebase and recommend corrective design patterns. Use when reviewing code for design quality, investigating why changes are difficult, or auditing coupling and inheritance depth. Scans for 8 categories of design fragility — hardcoded object creation, operation dependencies…
Skill Claude CodeCodex
Implement the Strategy pattern to encapsulate a family of interchangeable algorithms behind a common interface. Use when you have multiple conditional branches selecting between algorithm variants, when algorithms need different space-time trade-offs, when a class has multiple behaviors expressed as conditionals, or…
Skill Claude CodeCodex
Choose the right structural design pattern (Adapter, Bridge, Composite, Decorator, Facade, Flyweight, or Proxy) for a structural design problem. Use when you need to adapt interfaces between incompatible classes, decouple an abstraction from its implementation so both can vary independently, build part-whole…
Skill Claude CodeCodex
Implement the Visitor pattern to define new operations on an object structure without changing the classes of the elements it operates on. Use when you have a stable class hierarchy but frequently add new operations, when many unrelated operations need to be performed on an object structure, or when you want to…
Plugin Claude Code
14 agent skills for designing data-intensive systems — data models, storage engines, replication, partitioning, transactions, distributed failures, consistency, batch/stream processing, and data integration architecture. From Designing Data-Intensive Applications by Martin Kleppmann.
Skill Claude CodeCodex
Design batch data processing pipelines for large-scale, bounded datasets processed offline. Use when building ETL workflows, processing logs or clickstream data at scale, generating ML feature pipelines or search indexes, or joining two large datasets that cannot fit in memory. Trigger phrases: "design a batch…
Skill Claude CodeCodex
Scan application code, SQL queries, or ORM code for exposure to the 6 database concurrency anomalies and produce a findings report with severity, affected locations, and fix recommendations. Use when: debugging a nondeterministic data corruption or race condition bug under concurrent load; auditing transaction code…
Skill Claude CodeCodex
Choose the correct consistency model (linearizability, causal consistency, or eventual consistency) for each operation in a distributed system, and select the matching implementation mechanism. Use when designing a new distributed data system, deciding whether ZooKeeper or etcd is needed for coordination, evaluating…
Skill Claude CodeCodex
Design the integration architecture for systems with multiple specialized data stores (Postgres, Elasticsearch, Redis, data warehouses) that must stay in sync. Use when deciding how data flows between components, avoiding dual writes, reasoning about correctness across system boundaries (idempotency, end-to-end…
Skill Claude CodeCodex
Choose between relational, document, and graph data models for an application by analyzing data shape, relationship complexity, and query patterns. Use when asked "should I use MongoDB or PostgreSQL?", "when does a graph database make sense?", "how do I choose between SQL and NoSQL?", or "what data model fits my…