Testing and QA: skills, plugins, subagents, slash commands and mcp servers

improve-codebase-architecture Matt Pocock skill This skill scans a codebase for architectural friction, then builds a visual HTML report with refactoring candidates. Use it before a deeper architecture review. Claude Code 1,163,035installs design-taste-frontend Leonxlnx skill This skill directs the design of public pages and work screens, then checks the result in a browser through screenshots. Use it when an interface feels generic or unfinished. Claude Code CX Codex Cursor +1 673,100installs tdd Matt Pocock skill Guides the red-green TDD loop: ensures tests are written first, keep them at public interfaces, and avoid coupling to implementation details. Claude Code 1,141,062installs skill-creator official anthropics skill Creates and refines skills, then tests them with prompts, evaluations, and performance checks. Claude Code Claude.ai 414,180installs agent-browser vercel-labs skill A CLI skill for browser control: it opens pages, fills forms, clicks buttons, and tests web apps. Use it when an agent needs to act inside a website. Claude Code CX Codex Cursor +1 1,200,000installs prototype Matt Pocock skill Creates throwaway prototypes for checking state logic or exploring UI before committing the decision to the main codebase. Claude Code 986,201installs codebase-design Matt Pocock skill This skill helps design modules with small interfaces and hidden complexity. Use it when refactoring code, choosing a seam, or making tests easier to write. Claude Code 850,344installs diagnosing-bugs Matt Pocock skill This skill guides agents through reproducing hard bugs and performance regressions with a focused feedback loop. Use it when code fails, behaves incorrectly, or runs slowly. Claude Code 834,802installs implement Matt Pocock skill Implements work from a specification or tickets, following a test-driven flow and ending with review and a commit. Use it when a coding task needs a defined delivery routine. Claude Code 774,700installs to-spec Matt Pocock skill Turns the current conversation and repository context into a spec, then publishes it to the project issue tracker. Use it when a feature discussion is ready to hand off to an agent. Claude Code 715,388installs setup-pre-commit Matt Pocock skill This skill configures pre-commit checks for a JavaScript repository, running Prettier, type checking, and tests before each commit. Claude Code 489,289installs webapp-testing official anthropics skill This skill tests local web apps with Playwright, helping agents debug UI behavior, capture screenshots, and inspect browser logs. Claude Code Claude.ai 186,758installs migrate-to-shoehorn Matt Pocock skill Replaces as type assertions in tests with helpers from @total-typescript/shoehorn. Use it when tests need partial objects or deliberately invalid data. Claude Code 475,388installs systematic-debugging Jesse Vincent skill Makes the agent investigate the cause of a failure before it suggests a patch. Use it for failing tests, build errors, and behaviour that does not match expectations. Claude Code CX Codex 306,118installs requesting-code-review Jesse Vincent skill Sends completed work to a reviewer subagent after a task, major feature, or before merging to main. It keeps the review focused on the change and its requirements. Claude Code CX Codex 262,135installs test-driven-development Jesse Vincent skill This skill guides an agent through test-first development: verify a test fails, write the smallest passing change, then refactor. It covers features, bug fixes, and behavior changes. Claude Code CX Codex 259,292installs verification-before-completion Jesse Vincent skill This skill blocks completion claims until the agent runs a fresh check and reads the result. Use it before commits or PRs when an agent report is not enough. Claude Code CX Codex 251,313installs executing-plans Jesse Vincent skill Runs an implementation plan in the current session instead of assigning each task to a subagent. Use it for inline work with TDD, a decision ledger, and a final branch review. Claude Code CX Codex 242,988installs receiving-code-review Jesse Vincent skill Reviews code review feedback before changes: it clarifies unclear points, checks the repository, and supports reasoned pushback. Use it before acting on review comments. Claude Code CX Codex 221,216installs dispatching-parallel-agents Jesse Vincent skill Dispatches independent tasks to separate subagents so they can investigate them in parallel. Use it for unrelated test failures and separate broken subsystems. Claude Code CX Codex 218,235installs writing-skills Jesse Vincent skill Applies a TDD workflow to authoring and checking agent skills: observe failure first, then write instructions that address it. Use it when creating or editing SKILL.md files. Claude Code CX Codex 217,894installs using-git-worktrees Jesse Vincent skill Prepares an isolated workspace before feature work or plan execution. It checks the repository first, then uses native worktree support or Git. Claude Code CX Codex 217,153installs finishing-a-development-branch Jesse Vincent skill This skill checks the test suite and guides branch completion: merge locally, open a Pull Request, or leave the work in place. Claude Code CX Codex 214,439installs implement-spec Matt Pocock skill Implements a prepared spec from its ticket graph on one integration branch, using parallel subagents. Use it when tickets have blocking dependencies. Claude Code 283,700installs retro Matt Pocock skill Reviews a coding session and suggests changes to the agent environment for later runs. Use it after mistakes, slow repository navigation, or costly tool calls. Claude Code 276,027installs remotion-to-hyperframes heygen-com skill Imports Remotion animations or video footage into HyperFrames and verifies visual matching frame by frame against the original. Claude Code CX Codex Cursor +1 504,900installs google-agents-cli-eval official Google skill Guides testing, dataset setup, and scoring for AI agents via agents-cli. Useful for inspecting failures and running prompt optimization under the Gemini methodology. Claude Code CX Codex Cursor +1 510,000installs google-agents-cli-workflow official Google skill This skill guides ADK agent work from scaffolding through deployment and observability. Use it when an agent must be run, tested, published, or debugged. Claude Code CX Codex Cursor +1 510,000installs ponytail DietrichGebert skill ponytail puts an agent into a senior-dev mode focused on the smallest complete change. Use it when you want clear replies and less code added to a project. Claude Code CX Codex Cursor +1 105,000installs browser-use browser-use skill Hands the agent a real Chrome over CDP: clicks, typing, screenshots, and pages that need JS or your logged-in session. Claude Code CX Codex Cursor +1 98,100installs ponytail-review DietrichGebert skill ponytail-review reviews a change beyond the diff, checking connected code, bugs, risks, load, tests, speed, and unnecessary code. Use it for PRs and commits. Claude Code CX Codex Cursor +1 56,300installs caveman-optimize JuliusBrussee skill This skill turns a Caveman report observation into an operator-selected candidate and a paired baseline evaluation. Approval is required before code changes. Claude Code CX Codex Cursor +1 104,800installs ponytail-audit DietrichGebert skill It audits a repository and ranks bugs, risks, and redundant code in a one-shot report. Use it when you need a review without code changes. Claude Code CX Codex Cursor +1 44,800installs investigate-first JuliusBrussee skill The skill keeps the agent in diagnosis mode: gather evidence, rank hypotheses, name the cause. Only then does it touch code. Claude Code CX Codex Cursor +1 104,400installs verify-and-stop JuliusBrussee skill Proves existing work meets acceptance criteria without expanding scope. Useful for validation tasks and last-mile checks. Claude Code CX Codex Cursor +1 104,000installs surgical-patch JuliusBrussee skill The skill constrains AI coding agents to the narrowest layer responsible for a bug. It prevents unwanted refactoring and demands focused regression checks. Claude Code CX Codex Cursor +1 103,800installs caveman-manage JuliusBrussee skill The skill reads an experiment's state and results in Caveman Cloud, weighs the evidence, then reports one recommendation or blocks the action. Claude Code CX Codex Cursor +1 103,300installs code-review-and-quality addyosmani skill Five review axes and a limit on diff size, so an agent checks a change before merge instead of after. Claude Code CX Codex Cursor +1 72,500installs security-and-hardening addyosmani skill Guides threat modeling and security checks for code that handles user input, authentication, sessions, or external services. Use it when building a feature that accepts untrusted data or reviewing code before release. Claude Code CX Codex Cursor +1 69,400installs debugging-and-error-recovery addyosmani skill This skill guides an agent from reproducing a failure to checking the fix. Use it when tests fail, a build breaks, or runtime behavior differs from expectations. Claude Code CX Codex Cursor +1 62,200installs