develop

Use when tests pass locally but fail in CI, pass some runs and fail others, or someone suspects a test is unreliable but cannot reproduce the failure consistently. Diagnoses root causes and provides concrete fixes. Triggers on: "flaky test", "intermittent test failure", "passes locally fails in CI", "test is non-deterministic", "random test failure", "테스트가 가끔 실패", "간헐적 테스트 오류", "CI에서만 실패하는 테스트", "flaky". Best for: timing races, shared state pollution, ordering dependencies, CI environment differences. Not for: consistently failing tests with a known error (those are bugs, not flakiness).

Use when someone needs to build or fix UI — React components, page layouts, client-side interactivity, data-fetching hooks, styling, or form handling. Defaults to Next.js App Router, TypeScript, and Tailwind. Triggers on: "build a React component", "Next.js page", "Tailwind styling", "fix this UI", "data fetching hook", "form validation", "React 컴포넌트 만들기", "프론트엔드 개발", "UI 구현", "Next.js App Router". Best for: React/Next.js components, custom hooks, TanStack Query integration, Zod form validation. Not for: Vue, Svelte, or non-React frontends; backend APIs (use spring-boot-engineer or relevant server skill).

Guides the developer-side incident lifecycle from triage through mitigation to blameless RCA — with severity classification, Slack update templates, escalation paths, and a structured post-mortem format. Use when a production issue is active or recently resolved and you need a fast, structured response rather than ad-hoc troubleshooting, or when writing a post-mortem after the fact. Not for designing SLOs, alerting rules, or reliability posture — use sre-engineer for that.

Use when someone is writing Kotlin code and needs idiomatic guidance — coroutine and Flow patterns, Kotlin Multiplatform (KMP) structure, Android with Jetpack Compose, Ktor server setup, or type-safe DSL authoring. Triggers on: "Kotlin coroutines", "KMP", "Kotlin Multiplatform", "Jetpack Compose", "Ktor server", "Flow", "suspend function", "코틀린", "코루틴", "안드로이드 Compose", "KMP 설정". Best for: idiomatic coroutine patterns, multiplatform source-set structure, Compose UI. Not for: general Java backend (use spring-boot-engineer), Android XML layouts.

Use when someone wants to expose an external service or API as a tool an LLM can call — building an MCP server from scratch, designing tool schemas, handling auth, or structuring resources and prompts. Triggers on: "build an MCP server", "MCP tool", "expose this API to Claude", "Model Context Protocol server", "MCP 서버 만들기", "외부 API를 LLM 도구로 노출", "MCP tool schema", "FastMCP", "MCP SDK". Best for: TypeScript MCP SDK, Python FastMCP, tool schema design, evaluation creation. Not for: CLI wrappers without MCP protocol (use cli-developer); general API integrations.