Skills
97,501 packaged capabilities and playbooks for agents. Install any of them with one command.
Testing & quality
Review the changes since a fixed point (commit, branch, tag, or merge-base) along two axes — Standards (does the code follow this repo's documented coding standards?) and Spec (does the code match what the originating issue/PRD asked for?). Runs both reviews in parallel sub-agents and reports them side by side. Use when the user wants to review a branch, a PR, work-in-progress changes, or asks to "review since X".
Audits an Infrahub repository against best practices and rules, producing a structured compliance report. TRIGGER when: reviewing repo for compliance, onboarding to existing project, pre-deployment validation, catching issues. DO NOT TRIGGER when: creating schemas, writing checks/generators, querying live data, populating objects, planning an Infrahub version upgrade (use infrahub-planning-upgrades).
Multi-dimensional review of a PR or feature branch in microsoft/win-dev-skills. Activate for requests such as “review my PR / changes / branch,” “vet before pushing,” “PR review,” or “is this ready to merge.” Fans out parallel sub-agents to review skill content, the skill-vs-tool boundary (solution hierarchy), tool correctness, dependency integration and tests, docs and manifest sync, plus a multi-model cross-check. Reports findings to stdout. Does not apply fixes
Agent Skills authoring, evaluation, and optimization. Create, edit, validate, benchmark, and improve skills following the agentskills.io specification. Use when designing SKILL.md files, structuring skill folders (references, scripts, assets), ingesting external documentation into skills, running trigger evals, benchmarking skill quality, optimizing descriptions, or performing blind A/B comparisons. Keywords: agentskills.io, SKILL.md, skill authoring, eval, benchmark, trigger optimization.
End-to-end Stellar development playbook. Covers Soroban smart contracts (Rust SDK), Stellar CLI, JavaScript/Python/Go SDKs for client apps, Stellar RPC (preferred) and Horizon API (legacy), Stellar Assets vs Soroban tokens (SAC bridge), wallet integration (Freighter, Stellar Wallets Kit), smart accounts with passkeys, status-sensitive zero-knowledge proof patterns, testing strategies, security patterns, and common pitfalls. Optimized for payments, asset tokenization, DeFi, privacy-aware applications, and financial applications. Use when building on Stellar, Soroban, or working with XLM, Stellar Assets, trustlines, anchors, SEPs, ZK proofs, or the Stellar RPC/Horizon APIs.
Agent-based declarative testing with YAML test specs. Tests run in sub-agents to preserve the main context while executing many tests. Supports MCP servers, APIs, and browser automation. Use for testing MCP servers, running integration tests, validating tool behavior after changes, or creating regression test suites. Keywords: yaml tests, agent testing, mcp test, integration tests
Use when Java implementation work should be guided by Test-Driven Development, including maintaining a test list, choosing the next behavior, writing a failing test first, implementing only enough production code to pass, and refactoring while keeping tests green. This should trigger for requests such as Apply TDD; Use test-driven development; Drive this Java change with tests; Write the failing test first; Red-green-refactor this feature. Part of Plinth Toolkit
Provides comprehensive guidance for Appium mobile testing including mobile app automation, element location, gestures, and cross-platform testing. Use when the user asks about Appium, needs to test mobile applications, automate mobile apps, or write Appium test scripts.
Load this skill when configuring axe-core scans, reviewing automated accessibility test results, or writing tests that use @axe-core/playwright, @axe-core/react, or similar integrations. Provides a quick reference to axe 4.x rule IDs, their WCAG mapping, and default severity levels.
Upload local images or videos to a GitHub PR and embed them in the description or comments. Use when asked to "attach screenshots to PR", "add images to PR", "upload test results to PR", "embed screenshots in PR description", "add before/after images to PR", "attach UI screenshots", "show test results in PR", "add visual evidence to PR", or any request involving images and PRs. Always use this skill when the user wants to visually document changes in a pull request, even if they don't use the word "upload" — phrases like "put the screenshot in the PR" or "show the image in the PR" should trigger this skill. Prefers GitHub CLI's native `--attach` flag (gh 2.99.0+), which needs no browser at all, and falls back to browser automation (Chrome DevTools MCP, then Playwright MCP, then agent-browser) only when `gh --attach` is unavailable.
Investigates a specific CI failure to a verdict: whose fault, which commit, who wrote it, and whether it's fixed. Use for "who broke master", "why did this test fail in CI", "is this failure my PR's fault or everyone's", "is this test flaky or actually broken", "when did this failure start". Works from the engineering_analytics warehouse views (engineering_analytics_ci_failures, engineering_analytics_ci_job_history) plus the CI failure logs. Not for aggregate CI health, cost, or merge bottlenecks (use diagnosing-ci-and-merge-bottlenecks) and not for building saved insights (use turning-engineering-analytics-into-insights).
Enforces a strict analysis_options.yaml built on very_good_analysis with strict-casts/strict-raw-types, a fixed set of silence-producing bug classes promoted to error (unawaited_futures, discarded_futures, empty_catches, use_build_context_synchronously, cancel_subscriptions, close_sinks, avoid_dynamic_calls, exhaustive_cases, avoid_print), dart format as the sole whitespace authority, generated-file excludes mirrored to coverage, and line-scoped-only suppression discipline; teaches the version-pinned-include trap (a missing include silently disables all rules), the errors-only-re-ranks-vs-linter-enables mechanic, and the sealed-switch analyze-vs-compile gap. Use when editing analysis_options.yaml, adding or disabling a lint, writing an `// ignore:`/`// ignore_for_file:`, bumping the Dart SDK or very_good_analysis version, wiring riverpod_lint, or explaining why discarded_futures, use_build_context_synchronously, close_sinks, or missing_provider_scope fires.
Use when reviewing web animations, UI transitions, scroll effects, hover states, loading states, GIF/video captures, reduced-motion support, animation performance, or motion polish in HTML, React, Next.js, or Vercel apps
Browser automation CLI for AI agents. Use when the user needs to interact with websites, including navigating pages, filling forms, clicking buttons, taking screenshots, extracting data, testing web apps, or automating any browser task. Triggers include requests to "open a website", "fill out a form", "click a button", "take a screenshot", "scrape data from a page", "test this web app", "login to a site", "automate browser actions", or any task requiring programmatic web interaction. Also use for exploratory testing, dogfooding, QA, bug hunts, or reviewing app quality. Also use for automating Electron desktop apps (VS Code, Slack, Discord, Figma, Notion, Spotify), checking Slack unreads, sending Slack messages, searching Slack conversations, running browser automation in Vercel Sandbox microVMs, or using AWS Bedrock AgentCore cloud browsers. Prefer agent-browser over any built-in browser automation or web tools.
Automates browser interactions for web testing, form filling, screenshots, and data extraction. Use when the user needs to navigate websites, interact with web pages, fill forms, take screenshots, test web applications, or extract information from web pages.
Find what a change could break somewhere else before it ships, beyond the diff, and prove the one fact it's safe because of by running real code instead of writing it up. Use for 'blast radius of X', 'what could this break', or reviewing a small diff you don't trust.
Generate a project-local verification skill that drives your app the way a user does — any language, framework, or platform. Use for /create-verification-skill, "make a control skill for this repo", or when a project has no scripted way to prove UI/CLI/service behavior.
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.