Skills
96,770 packaged capabilities and playbooks for agents. Install any of them with one command.
Testing & quality
Provides patterns for unit testing Jakarta Bean Validation (JSR-380), including @Valid, @NotNull, @Min, @Max, @Email constraints with Hibernate Validator. Generates custom validator tests, constraint violation assertions, validation groups, and parameterized validation tests. Validates data integrity logic without Spring context. Use when writing validation tests, bean validation tests, or testing custom constraint validators.
Four-mantra debugging discipline — reproduce, trace the fail path, falsify the hypothesis, cross-reference every breadcrumb. Recite the mantra block verbatim at the start of any debugging session, then apply the four steps in order before proposing any fix. Trigger on /debug-mantra and proactively whenever debugging starts — a user reports a bug, says something is broken/throwing/failing, asks to debug/diagnose/investigate an issue, or pastes a stack trace or error log.
Create custom Code Analyzer rules for Regex (pattern matching), PMD (XPath/AST for Apex and metadata XML), and ESLint (LWC/JavaScript/TypeScript). Use when users want to enforce coding standards, ban patterns, detect hardcoded values, govern metadata, or add rules not in the built-in set. TRIGGER when: user says 'create a rule', 'ban System.debug', 'enforce naming convention', 'detect hardcoded IDs', 'custom rule', 'xpath rule', 'regex rule', 'add a PMD rule', 'enforce a policy', 'create a check for', 'flag this pattern', 'make a rule that catches', 'metadata rule', 'check permissions', 'enforce API version', 'eslint rule', 'lwc rule', 'override rule threshold', 'customize complexity', or describes a pattern to enforce. DO NOT TRIGGER when: user wants to run a scan (use dx-code-analyzer-run), configure engines (use dx-code-analyzer-configure), or explain existing rules (use dx-code-analyzer-run).
INVOKE THIS SKILL when creating evaluation datasets, uploading datasets to LangSmith, or managing existing datasets. Covers dataset types (final_response, single_step, trajectory, RAG), CLI management commands, SDK-based creation, and example management. Uses the langsmith CLI tool.
Find the mistakes agents keep repeating in this repo and make each one impossible. Try architecture first, then types, then a lint whose error names the fix, then a test, and write docs last. Prove each check fails on a real past mistake. Repeat this each time the operator corrects you. Use for /correct.
Salesforce Industries Common Core (OmniStudio/Vlocity) Apex callable generation and review skill with 120-point scoring. Use when creating, reviewing, or migrating Industries callable Apex implementations. TRIGGER when: user creates or reviews System.Callable classes, migrates VlocityOpenInterface or VlocityOpenInterface2, or builds Industries callable extensions used by OmniStudio, Integration Procedures, or DataRaptors. DO NOT TRIGGER when: generic Apex classes or triggers (use platform-apex-generate), building Integration Procedures (use omnistudio-integration-procedure-generate), authoring OmniScripts (use omnistudio-omniscript-generate), configuring Data Mappers (use omnistudio-datamapper-generate), or analyzing namespace/dependency issues (use omnistudio-dependencies-analyze).
Verify and debug native, React Native, Expo, or Flutter apps on an Android Emulator with agent-device. Use when an agent needs to launch an app, inspect its live UI, tap, type, scroll, validate a code change, collect failure evidence, or reproduce a workflow on an Android virtual device
Store inspection workflow: orchestrates store list + store open + page visit + page screenshot to complete store status checks and screenshot inspections. Suitable for periodically checking store page status and archiving screenshots in batches.
Pre-launch checklist for shipping a new website or web app. Scope: analytics (GA4, PostHog, Google Search Console, Ahrefs), DNS, TLS and backups, legal and CNIL/GDPR compliance, security headers, SEO and GEO (robots.txt, sitemaps, llms.txt, hreflang, schema markup, keyword research), copywriting voice via TONE.md and a humanizer pass, OpenGraph and social previews, favicons and web manifest, Lighthouse, Core Web Vitals and WCAG quality gates, directory submissions, Product Hunt, G2/Capterra reviews, post-launch monitoring. Use when the user says 'checklist for the site', 'ready to ship', 'before I go live', 'ready for prod', 'audit before launch', or asks for a site review, pre-launch audit, or help launching a site or app, deploying a domain to production, or shipping a marketing, docs, SaaS, or lead-magnet site.
Review generated or changed production code before it ships, using Clean Code, SOLID, DRY, KISS, YAGNI, and LLM-specific failure-mode checks in any programming language. Best used reactively after an agent writes, edits, refactors, or fixes code, before presenting, committing, or merging the result. Use when the user asks "review this PR", "is this safe to merge?", "make this cleaner", "audit this code", "refactor this", "fix this bug", or after a coding agent produced implementation code. Can also guide writing when explicitly invoked before a risky edit. Invoke it on your own initiative the moment you finish writing, editing, or refactoring non-trivial production code, before presenting or committing — don't wait to be asked. DO NOT USE for factual/conceptual questions, CI/tooling config, git workflow, running/debugging tests, pure architecture discussion, prose writing, data analysis, or test-code review (use test-guard).
Review code for logging patterns and suggest evlog adoption. Optionally use the evlog CLI, shipped with the evlog package (`evlog init` to wire evlog, `evlog agents` to write the conventions into AGENTS.md, `evlog map` to score entry-point coverage, `--baseline` to gate regressions in CI) on Nuxt, Nitro, Next.js, TanStack Start, Hono, Express, and Fastify. Guides setup on those plus SvelteKit, React Router, NestJS, Express, Fastify, Elysia, oRPC, Effect, Cloudflare Workers, AWS Lambda, Astro, and standalone TypeScript. Detects console.log spam, unstructured errors, and missing context. Covers wide events, structured errors, drain adapters (Axiom, OTLP, HyperDX, Sazabi, PostHog, Sentry, Better Stack, Datadog, Loki, ClickHouse, NuxtHub, Memory), sampling, enrichers, and AI SDK integration.
Review a Lightning Web Component for **mobile offline** compatibility — the Komaci offline static analyzer that pre-primes the data graph for Salesforce Mobile App Plus and Field Service Mobile App. Produces a finding list with code-level fixes covering inline GraphQL queries in `@wire` configurations, modern `lwc:if` / `lwc:elseif` / `lwc:else` directives, and Komaci ESLint rule violations (private wire properties, non-local reactive references, getter side-effects). Use when the user asks for a "mobile offline review", "Komaci check", "offline priming audit", "offline priming failure", or "offline data graph error", or to validate an LWC against the `@salesforce/eslint-plugin-lwc-graph-analyzer` recommended ruleset. Do not use for generic LWC code review (use an appropriate domain review skill) or for building LWCs with native mobile capabilities (use `mobile-platform-native-capabilities-integrate`).
Provides guidance and instructions on managing remote devices on Developer Device Platform (DDP). Use when reserving remote Android devices, establishing connection tunnels, checking session status, or extending/cancelling leases. Don't use for iOS or local device/hardware inquiries.
Profile, diagnose, and remediate SwiftUI runtime performance using code review, Instruments, and repeatable measurements. Use when a SwiftUI screen renders slowly, scrolling or animations hitch, view bodies update excessively, list identity churns, layout work spikes, or broad Observation dependencies raise CPU cost. Covers evidence-based triage, SwiftUI Instruments lanes, lazy-container guardrails, state lifetime, and before/after verification
Use for software implementation, debugging, refactoring, review, migration, and other repository-changing engineering work where correctness must be verified. Enforces scoped reconnaissance, adaptive planning, evidence-backed verification, requirement tracking, failure recovery, and budget-aware delegation. Model-agnostic reliability runtime for coding agents -- measured, not claimed.
Audit a test file or suite; produce a severity-ranked diagnostic report. ALWAYS USE for tests that verify nothing, missing/tautological assertions, swallowed/broad exceptions, flaky/order-dependent tests, duplication, or magic values. Polyglot. DO NOT USE for direct edits: writing-mstest-tests owns supplied MSTest assertions/attributes/lifecycle; code-testing owns new tests. Exclude running tests, migration, assertion metrics (assertion-quality), raw .NET coverage collection (run-tests), non-.NET coverage collection/analysis (native tooling), project-wide .NET coverage/CRAP (coverage-analysis), named-target .NET CRAP (crap-score), behavioral/pseudo-mutation gaps (test-gap-analysis), test-mix/ happy-vs-error classification and trait distributions (test-tagging), or the testsmells.org catalog (test-smell-detection).
Create new skills, modify and improve existing skills, and measure skill performance. Use when users want to create a skill from scratch, edit, or optimize an existing skill, run evals to test a skill, benchmark skill performance with variance analysis, or optimize a skill's description for better triggering accuracy
Fix the visual diffs (and any non-visual checks) that have been reviewed and rejected on a Meticulous test run, following their review comments if given, plus any Agent swarm fix prompts on the same commit. Use when a user has reviewed the results of a test run and is handing off to an agent to implement the fixes, or when the `meticulous-review` skill hands off what needs fixing on a change you're working on.
Audits App Store submission readiness and rejection risk across current review guidelines, PrivacyInfo.xcprivacy and required-reason APIs, privacy labels, ATT, StoreKit payments, metadata, entitlements, widgets, and Live Activities. Use when preparing a submission, responding to rejection, reconciling privacy evidence, or separating upload blockers from cleanup.
Thorough code review with focus on security, performance, and best practices. Use when reviewing code, performing security audits, checking code quality, reviewing pull requests, or when the user mentions code review, PR review, security vulnerabilities, or performance issues
UI/UX best practices for web interfaces. Use when reviewing animations, CSS, audio, typography, UX patterns, prefetching, or icon implementations. Covers 11 categories from animation principles to typography. Outputs file:line findings.
Reference-only filter syntax for VSTest and MTP with MSTest, NUnit, xUnit v3, and TUnit. Load only after the platform/framework is known and a consumer needs to create or translate a filter. Do not load for unfiltered runs or platform detection. Used by run-tests and mtp-hot-reload; never invoke directly
Implement a task for which no visual diffs are expected end to end, using Meticulous to drive the implementation to a clean visual diff before opening a PR. Use when the task's whole premise is "the UI shouldn't change" — a dependency/version upgrade, a code refactor, a migration, or similar. Meticulous isn't just a final check here, it's the loop you iterate against while implementing.
Run /debug to find and fix a bug's root cause: a test failing for an unclear reason, /check verify finding a failure, or behavior being wrong. Runs a reproduce, localize, hypothesize, test, fix, verify loop, makes the minimal fix, and hands a regression test to /test. No features, no extra refactors.
Confirm a change before merge. `/check verify` drives the real app to prove behavior against the spec (every acceptance criterion met, every surface built). `/check review` runs a senior code review on a fresh model, one that did not write the code. Verify after /develop, review before a PR. Writes to docs/reviews/, never edits code.
Stop hook that blocks Claude from finishing until quality checks pass. Detects rationalization patterns (surface text heuristics), stale learning logs (filesystem mtime), and low disk space. Complements self-audit by mechanically enforcing learning capture habits. Use when Claude should be mechanically blocked from declaring work finished before quality checks and learning capture actually pass.
Opinionated production Python standards with automatic version detection (3.10-3.13). Use when writing, reviewing, or refactoring Python in repos that want modern type syntax, explicit condition checks where practical, pathlib operations, interface guidance, and pragmatic production patterns.
Measure mesh files against Design for Additive Manufacturing (DfAM) rules and report printability findings per process (FDM, SLS, SLA/DLP, metal PBF, MJF). Use when the user asks whether a part is printable, wants overhang/wall-thickness/support analysis of an `.stl`, `.obj`, `.ply`, or `.3mf` mesh, wants a build-orientation recommendation, or wants DfAM redesign guidance before slicing with `$gcode` or regenerating geometry with `$cad`.
Guides agents through integrating transactional email sending via Mailtrap's Email API, including sandbox testing, domain verification, and API authentication. Use when implementing email-sending features, debugging delivery issues, or setting up safe dev/staging email testing.
Writes and migrates Swift Testing framework tests with @Test, @Suite, #expect, #require, confirmation, traits, withKnownIssue, Attachment.record, processExitsWith exit tests and capture lists, Test.cancel, Issue.record warnings/manual failures, XCTest-to-Swift Testing migration, Xcode 27 interoperability modes, XCUITest UI-test boundaries, performance/snapshot boundaries, mocking, async patterns, and test organization. Use when writing tests, converting XCTest assertions such as XCTUnwrap or XCTFail, reviewing advanced Swift Testing API availability, or deciding when to keep XCTest/XCUITest.
Provides comprehensive code review for React applications, validating component architecture, hooks usage, React 19 patterns, state management, performance optimization, accessibility compliance, and TypeScript integration. Use when reviewing React code changes, before merging pull requests, after implementing new features, or to validate component architecture. Triggers on “review React code,” “React code review,” and “check my React components.”
Run /test to write a test suite for code you just built or changed, after implementing a feature, route, or fix. Targets uncommitted changes automatically, reads test preferences.json for your framework (asks and saves it if absent), and picks the right strategy per file: happy path, edge cases, error states, accessibility
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.
Configures mewt or muton campaigns, analyzes surviving mutants, and investigates bugs exposed by testing gaps. Use when setting up mutation testing, reviewing campaign results, identifying equivalent mutants, or finding bugs from surviving mutations.
Debug LangChain and LangGraph agents by fetching execution traces from LangSmith Studio. Use when debugging agent behavior, investigating errors, analyzing tool calls, checking memory operations, or examining agent performance. Automatically fetches recent traces and analyzes execution patterns. Requires langsmith-fetch CLI installed.
Write or review k6 documentation across the three k6 repositories - k6-DefinitelyTyped (TypeScript types), k6-docs (user documentation), and k6 (release notes / changelog). Applies k6 doc style conventions, generates TypeScript type definitions, drafts release notes, and validates examples by running them against k6@master. Use when working on k6 documentation, the k6 changelog, the k6 release notes, k6 API reference, k6 TypeScript types, load testing docs, or when the user asks to write, edit, or review anything in the k6, k6-docs, or k6-DefinitelyTyped repos - even if they don't explicitly say "documentation"
Probe, load-test, and instrument frontends from Grafana Cloud. Covers Synthetic Monitoring (HTTP / DNS / TCP / Ping / Traceroute / Multihttp / k6-browser scripted checks from 20+ global probes, alert on `probe_success` + TLS-cert expiry), Grafana Cloud k6 (distributed load tests across AWS load-zones, scenarios, `http_req_duration` thresholds, CI integration via `grafana/k6-action`), and Frontend Observability with Faro Web SDK (RUM, Core Web Vitals, custom events, `pushError`, distributed-trace correlation). Use when checking website / API uptime from multiple regions, gating a release on a load test, watching for TLS-cert renewal, instrumenting a React/Vue app, tracking Core Web Vitals, or correlating frontend errors to backend traces — even when the user says “is my login flow up?”, “monitor my API”, “ping our endpoint every minute”, “release-gate load test”, “browser performance monitoring”, “session replay”, or “RUM” without naming Synthetic Monitoring / k6 / Faro
Provides comprehensive testing patterns for Spring Boot applications covering unit, integration, slice, and container-based testing with JUnit 5, Mockito, Testcontainers, and performance optimization. Use when writing tests, @Test methods, @MockBean mocks, or implementing test suites for Spring Boot applications.
Audits code for unit and decimal-scaling bugs and annotates it with dimensional comments recording the units of each value. Use when someone asks to audit or review code for unit confusion, decimals or scaling mismatches, WAD/RAY scale errors, or the wrong token's decimals; to annotate units in a codebase; or to perform a dimensional analysis of a DeFi protocol, offchain code, or other arithmetic-heavy codebase. Catches formulas that combine values carrying different units or scales.
Review changes from a fixed point (commit, branch, tag, or merge-base) along two axes: Standards (Does the code follow the coding standards documented in this repository?) and Spec (Does the code meet the requirements of the source issue/spec?). The two reviews run in parallel subagents and are reported side by side. Use when the user wants to review a branch, PR, in-progress changes, or asks to “review since X”.
Primary Apex authoring skill for class generation, refactoring, and review. ALWAYS ACTIVATE when the user mentions Apex, .cls, triggers, or asks to create/refactor a class (service, selector, domain, batch, queueable, schedulable, invocable, DTO, utility, interface, abstract, exception, REST resource). Use this skill for requests involving SObject CRUD, mapping collections, fetching related records, scheduled jobs, batch jobs, trigger design, @AuraEnabled controllers, @RestResource endpoints, custom REST APIs, or code review of existing Apex.
Review generated or changed test code against universal testing rules before it ships. Best used reactively after an agent writes, edits, generates, or refactors tests, before presenting, committing, or merging them. Use for pytest (test_*.py, *_test.py), PHPUnit/Pest (*Test.php), Jest/Vitest (*.test.ts, *.spec.js), Go (*_test.go), files under tests/, __tests__/, or spec/, and review requests like 'write tests for X', 'add tests', 'test this', 'review these tests', or PR diffs containing tests. Can also guide test writing when explicitly invoked before the work. This skill is the quality gate that prevents AI-generated test bloat. DO NOT USE for production or implementation code review (use clean-code-guard), CI or test-runner configuration, running or debugging tests, or general architecture discussion.
Generate and validate Apex test classes with TestDataFactory patterns, bulk testing (251+ records), mocking strategies, assertion best practices, and disciplined test-fix loops. Use this skill when creating new Apex test classes, improving test coverage, debugging and fixing failing Apex tests, running test execution and coverage analysis, or implementing testing patterns for triggers, services, controllers, batch jobs, queueables, and integrations. Triggers on *Test.cls, *_Test.cls files, sf apex run test workflows, coverage reports, test-fix loops. Do NOT trigger for production Apex code (use generating-apex) or Jest/LWC tests.
Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep watching open PRs so fresh review feedback is surfaced promptly. Use when the user asks Codex to monitor a PR, watch CI, handle review comments, or keep an eye on failures and feedback on an open PR.
Apply to multi-step work (sweeps, migrations, runs of similar edits) and to how you stack commits and PRs. Break work into small units that each end in a verifiable state, check each before the next, and order delivery so the sequence proves itself to a reviewer.
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.