Testing & Debugging for Claude Code

Write idiomatic Elixir code with OTP patterns, supervision trees, and Phoenix LiveView. Masters concurrency, fault tolerance, and distributed systems.

Systematic error diagnosis and resolution using first-principle analysis. Use when encountering any error message, stack trace, or unexpected behavior. Supports replay functionality to record and reuse solutions.

Use this agent when distributed system errors occur and need coordinated handling across multiple components, or when you need to implement comprehensive error recovery strategies with automated failure detection and cascade prevention. Specifically:\\n\\n<example>\\nContext: A database service fails, and multiple dependent microservices start experiencing timeouts and connection errors. The team needs to correlate these errors, prevent cascading failures, and coordinate recovery.\\nuser: \"We h

Use this agent when you need to diagnose why errors are occurring in your system, correlate errors across services, identify root causes, and prevent future failures. Specifically:\\n\\n<example>\\nContext: Production system is experiencing intermittent failures across multiple microservices with unclear root cause.\\nuser: \"We have 50+ errors per minute in production with timeout exceptions in the API gateway, database connection errors, and queue failures. The incidents started after a deploy

Evaluates code generation models across HumanEval, MBPP, MultiPL-E, and 15+ benchmarks with pass@k metrics. Use when benchmarking code models, comparing coding abilities, testing multi-language support, or measuring code generation quality. Industry standard from BigCode Project used by HuggingFace leaderboards.

Provide expert C++ software engineering guidance using modern C++ and industry best practices.

Provide expert .NET software engineering guidance using modern software design patterns.

Perform comprehensive exploratory data analysis on scientific data files across 200+ file formats. This skill should be used when analyzing any scientific data file to understand its structure, content, quality, and characteristics. Automatically detects file type and generates detailed markdown reports with format-specific analysis, quality metrics, and downstream analysis recommendations. Covers chemistry, bioinformatics, microscopy, spectroscopy, proteomics, metabolomics, and general scientif

Plan and build production-ready FastAPI endpoints with async SQLAlchemy, Pydantic v2 models, dependency injection for auth, and pytest tests. Uses interview-driven planning to clarify data models, authentication method, pagination strategy, and caching before writing any code.

This skill should be used when the user asks to "test for directory traversal", "exploit path traversal vulnerabilities", "read arbitrary files through web applications", "find LFI vulnerabilities", or "access files outside web root". It provides comprehensive file path traversal attack and testing methodologies.

Please analyze and fix the GitHub issue: $ARGUMENTS.

Identify and resolve code issues

Framework for computational fluid dynamics simulations using Python. Use when running fluid dynamics simulations including Navier-Stokes equations (2D/3D), shallow water equations, stratified flows, or when analyzing turbulence, vortex dynamics, or geophysical flows. Provides pseudospectral methods with FFT, HPC support, and comprehensive output analysis.

Use PROACTIVELY to analyze game performance bottlenecks and generate optimization recommendations across multiple platforms

Use PROACTIVELY to implement comprehensive game testing frameworks with automated validation, performance testing, and multi-platform verification

Generate comprehensive test cases with automatic analysis and coverage optimization

Generate a complete test file for a specified source file or component. Use when the user explicitly asks to write, create, or generate tests for a specific file.

Inspect GitHub PR checks with gh, pull failing GitHub Actions logs, summarize failure context, then create a fix plan and implement after user approval. Use when a user asks to debug or fix failing PR CI/CD checks on GitHub Actions and wants a plan + code changes; for external checks (e.g., Buildkite), only report the details URL and mark them out of scope.

Use PROACTIVELY to guide automated git bisect sessions for finding regression commits with smart test execution

| A tool for creating and managing Garry's Mod addons, including Lua scripting, content creation, and addon packaging. Use when: developing new addons, writing Lua scripts for GMod, organizing addon files, or when user mentions Garry's Mod, GMod, Lua scripting, or addon development.

Expert assistant for building Model Context Protocol (MCP) servers in Go using the official SDK.

Query the code graph database to understand component relationships, dependencies, and change impact. Use when the user asks to "find callers", "check dependencies", "what uses this", "show relationships", "find serializers", or when reading code and needing to understand what depends on a component before modifications.

Use this agent when designing or evolving GraphQL schemas across microservices, implementing federation architectures, or optimizing query performance in distributed graphs. Specifically:\n\n<example>\nContext: A team is building a multi-service architecture and needs to design a federated GraphQL schema.\nuser: \"We have three services (users, orders, products) that need to be exposed through a unified GraphQL API. Can you design the federation structure?\"\nassistant: \"I'll analyze your servi

GraphQL performance analysis and optimization specialist. Use PROACTIVELY for query performance issues, N+1 problems, caching strategies, and production GraphQL API optimization. Specifically:\n\n<example>\nContext: An existing resolver file is causing visible slowdowns when loading lists of users with their related orders.\nuser: \"Our user list page takes 3–4 seconds to load. Each user has related orders fetched in a separate resolver. Can you diagnose and fix it?\"\nassistant: \"I'll scan the

Expert Haskell engineer specializing in advanced type systems, pure

Run comprehensive CI checks and fix issues until repository is in working state

Generate testable hypotheses. Formulate from observations, design experiments, explore competing explanations, develop predictions, propose mechanisms, for scientific inquiry across domains.

This skill should be used when the user asks to "test for insecure direct object references," "find IDOR vulnerabilities," "exploit broken access control," "enumerate user IDs or object references," or "bypass authorization to access other users' data." It provides comprehensive guidance for detecting, exploiting, and remediating IDOR vulnerabilities in web applications.

Expert SRE incident responder specializing in rapid problem resolution, modern observability, and comprehensive incident management.

Handles production incidents with urgency and precision. Use IMMEDIATELY when production issues occur. Coordinates debugging, implements fixes, and documents post-mortems.

Native iOS development specialist with Swift and SwiftUI. Use PROACTIVELY for iOS applications, UIKit/SwiftUI components, Core Data integration, app lifecycle management, and App Store optimization.

Master modern JavaScript with ES6+, async patterns, and Node.js APIs. Handles promises, event loops, and browser/Node compatibility.

Comprehensive k6 load testing skill for API, browser, and scalability testing. Write realistic load scenarios, analyze results, and integrate with CI/CD.

Expert patterns for Kotlin Coroutines and Flow, covering structured concurrency, error handling, and testing.

Expert assistant for building Model Context Protocol (MCP) servers in Kotlin using the official SDK.

Expert KQL assistant for live Azure Data Explorer analysis via Azure MCP server

Expert in Langfuse - the open-source LLM observability platform. Covers tracing, prompt management, evaluation, datasets, and integration with LangChain, LlamaIndex, and OpenAI. Essential for debugging, monitoring, and improving LLM applications in production. Use when: langfuse, llm observability, llm tracing, prompt management, llm evaluation.