Adversarial TS Patterns Gate

A design-pattern usage gate for TypeScript and React application code — a pass/fail gate: a single blind reviewer subagent judges the work against this gate's rules with an adversarial mandate, and the work passes only when every rule is PASS or N/A. This skill renders verdicts; it never fixes the work.

The gate judges in both directions. Over-abstraction — Gang of Four and enterprise machinery ported from Java/C# where idiomatic TypeScript reaches for a function, a module, or a tagged union. Under-modeling — implicit state machines whose impossible states compile: boolean-flag lifecycles, effect chains, hand-synced derived state, silent default branches.

When to Apply

• A TypeScript/React diff or feature is about to merge and needs an objective PASS/FAIL on pattern usage, not advisory feedback.
• An agent (Claude, Codex) authored the code and you want an independent check that it is not reproducing Java/C# training-data idioms — Singleton classes, factory hierarchies, repository wrappers, JavaBean accessors.
• A migration from another stack (Java, C#, Angular-style DI) claims completion and the ported architecture needs auditing for layers that lost their justification in TypeScript.
• Component or store state grew organically and you want the implicit-state-machine failure modes (contradictory booleans, effect chains, non-exhaustive matches) caught before they ship.

Do not apply to non-TypeScript codebases (the reviewer prompt's precondition aborts with "GATE NOT APPLICABLE"), or when the user wants explanations and refactors rather than a verdict — that is the job of the curated implementation-design-patterns and implementation-functional-patterns skills. React-specific rules go N/A in non-React TypeScript projects; the rest of the gate works in any TypeScript application.

Review Protocol

Follow these steps exactly — the gate's value is that every review runs the same way.