Use when jest configuration, setup files, module resolution, and project organization for optimal testing environments.

Write JavaScript/TypeScript tests with Jest including unit tests, mocking, snapshots, and coverage. Test React components, async code, and Node.js. Use for JavaScript testing, React testing, or test automation.

Jest testing patterns, anti-patterns, and quality rules

Comprehensive React component testing with Jest and React Testing Library covering configuration, mocking strategies, async testing patterns, hooks testing, and integration testing best practices

Scaffolds Jest unit tests for React components and hooks. Use when creating tests for frontend components.

Execute and generate Jest tests for JavaScript/TypeScript projects with support for unit, integration, and E2E testing

Expert assistant for Juju charm development using jhack utilities. Use when debugging charms, inspecting relations, syncing code, replaying events, testing scenarios, or performing rapid development iterations. Keywords include jhack, Juju debugging, charm testing, relation inspection, event replay, sync, tail, fire, show-relation, show-stored.

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Expert in mapping SpecWeave increments to JIRA structure (Increment → Epic + Stories + Subtasks) with bidirectional sync. Use when exporting increments to JIRA, importing JIRA epics as increments, or configuring field mapping. Maintains traceability across systems.

Use jira CLI for Jira operations including issue management, project queries, transitions, and JQL search

Sync guidance for SpecWeave increments with JIRA epics/stories (content SpecWeave→JIRA, status JIRA→SpecWeave). Use when asking about JIRA integration setup or troubleshooting sync. For actual syncing, use /sw-jira:sync command instead.

This skill should be used when estimating development time for Jira tickets. It provides both manual and AI-assisted estimates with T-shirt sizes, story points, and phase-by-phase time breakdowns based on task type classification, complexity scoring, and project architecture (monolithic/serverless/frontend/fullstack/mobile/test_automation).

This skill should be used when users need to fetch Jira ticket content using either a specific ticket ID (like RD-3891) or search for tickets by title/description. It defaults to searching within the current sprint but can extend to all tickets when needed. The skill uses the Jira CLI to retrieve ticket details, status, assignee, and descriptions.

Control Chrome browser via CLI for testing, automation, and debugging. Use when the user needs browser automation, screenshots, form filling or page inspection.

Jira ticket creation and management for AI agent commands, with severity-based processing and proper integration

Master Jito bundles for MEV protection and priority fee optimization on Solana - bundle submission, tip strategies, and transaction landing. Use for trading bots, high-priority transactions, and MEV-aware applications.

Integrate third-party repository history into the monorepo by adding remotes and creating workspaces. Use when testing patches to upstream projects, making local modifications to dependencies, or maintaining forks that need to track upstream changes. (project)

Create isolated jj workspaces for testing changes, running experiments in parallel, and exploring alternative implementations. Use when testing breaking changes, comparing different approaches, or running long-running operations without blocking other work. (project)

Search the JLCPCB electronic components database (~7 million parts) for hardware/electronics projects. Use when the user needs to: (1) Find electronic components (resistors, capacitors, ICs, connectors, etc.), (2) Look up specific part numbers or manufacturers, (3) Find alternatives or equivalents for components, (4) Check component availability and stock at JLCPCB, (5) Get component specifications (package type, description, etc.), or (6) Search for parts for PCB assembly projects.

Search for jobs at a company OR parse a specific job posting. Extracts requirements, calculates fit scores, and tracks market skills.

Extract specific fields from JSON files efficiently using jq instead of reading entire files, saving 80-95% context.

Enforce ESLint standards by fixing violations systematically

Fix JSDoc errors and warnings from build/lint with content preservation

Self-contained command for coverage generation and analysis

Jobs to Be Done (JTBD) framework by Clayton Christensen. Analyzes requirements through the lens of what 'job' customers hire products to do. Covers functional, emotional, and social jobs. Use when understanding underlying customer motivations or reframing features as outcomes.

Expert guidance for Julia package development following SciML standards, Distributions.jl patterns, and Julia ecosystem best practices

Guide for creating Claude Code hooks - shell commands that execute at specific lifecycle events (SessionStart, SessionEnd, PreToolUse, PostToolUse, etc.). Use when users want to automate actions, add validation, logging, or integrate external tools into Claude Code workflows.

Get OpenAI Codex CLI's opinion on code, bugs, or implementation. Use when you want a second AI perspective during coding sessions.

Get Gemini CLI's opinion on code, architecture, or implementation. Use when you want a second AI perspective during coding sessions.

JUnit 5 core testing patterns with AAA structure, test organization, and coverage standards

Use when jUnit extensions including custom extensions, rules, and conditional test execution.

Use when jUnit fundamentals including annotations, assertions, and test lifecycle for Java testing.

Maven integration testing with Failsafe plugin, IT naming conventions, and profile configuration

Use when jUnit parameterized tests with various value sources and test factories.

Integrate Jupiter aggregator for swaps - API usage, route optimization, slippage handling, and frontend/bot implementation. Use when building swap UIs or trading bots.

- [Execution Enforcement](#execution-enforcement)

Best practices for using just command runner and task automation in development workflows.

This skill provides patterns for setting up just (command runner) in projects. Use PROACTIVELY when creating build systems, setting up new repos, or when the user asks about just/justfile configuration. Covers both simple single-project repos and monorepos with hierarchical justfile modules.

Just command runner for saving and running project-specific commands

Level 3 patterns - test-smart, deploy, migrate, logs, status (production systems)

Five-level maturity progression - assessment criteria, upgrade paths, YAGNI enforcement

Ralph research agent for discovering global youth justice cases and advocacy campaigns

Expert JVZoo integration specialist for building backend systems that handle JVZoo purchases, create user accounts, manage software licenses, and process IPN notifications. Use when implementing JVZoo product licensing, account creation workflows, payment processing, refund handling, or connecting software products to JVZoo marketplace by product ID.

Identify and exploit vulnerabilities in JSON Web Token (JWT) implementations, including algorithm confusion attacks, secret key cracking, signature bypass, and claim manipulation. JWTs are widely used

Эксперт k6 нагрузочного тестирования. Используй для performance testing, load scenarios и stress tests.

kafka-consumer-implementation

Expert in Apache Kafka, Event Streaming, and Real-time Data Pipelines. Specializes in Kafka Connect, KSQL, and Schema Registry.

kafka-integration-testing

MCP server integration for Kafka operations with Claude Desktop and SpecWeave. Use when configuring Kafka MCP servers, connecting Claude to Kafka topics, or choosing between MCP implementations.

kafka-producer-implementation