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Claude Code Extensions — Skills, Hooks, Plugins and MCP
Claude Code is extensible in four distinct ways — and "extension" is a synonym for any of them depending on who you ask. This page is the disambiguation table plus the open catalog.
Claude Code is extensible in four distinct ways — and "extension" is a synonym for any of them depending on who you ask. This page is the disambiguation table plus the open catalog.
(1) Skills — SKILL.md files under ~/.claude/skills/. The most common shape: a named, invokable task that Claude picks up when relevant. ClaudSkills catalogs 67,000+. See /skills/.
(2) Hooks — shell commands wired into settings.json, fired at lifecycle events. Deterministic, not model-judged. See /learn/claude-code-hooks/.
(3) MCP servers — standalone processes Claude Code connects to over the Model Context Protocol, exposing tools and data sources. The driver layer. See /arcade/mcp-server/ for raw servers and /learn/claude-code-mcp-servers/ for skills that use them.
(4) Slash commands — Markdown files under ~/.claude/commands/ that the user invokes with /<name>. Lighter-weight than skills; no allowed-tools declaration, no auto-discovery in conversation.
The listing below is the top-quality slice of all four, ranked by the content-derived ClaudSkills quality score.
Top 40 indexed skills
- coverTools
Generate and run comprehensive test suites — unit tests, integration tests with real services (testcontainers/docker-compose), and Playwright E2E tests. Analyzes coverage gaps, spawns parallel test-generator agents…
- sales-attioSales
Attio platform help — AI-native CRM with custom objects, relationship database, deal pipelines, email sequences, automations, and built-in enrichment for 80,000+ startups. Covers custom data model design (objects,…
- sales-hypeauditorSales
HypeAuditor platform help — AI-powered influencer marketing with Influencer Discovery (223.6M+ profiles across Instagram, TikTok, YouTube, X, Twitch, Snapchat), Analytics Reports (35+ metrics, AQS scoring), Fraud…
- webapp-paywall-implementationGeneral
Implement paywalls, subscription billing, and feature gating in web applications. Covers Stripe/Lemon Squeezy/Paddle integration, subscription lifecycle management, React/Next.js gating patterns, webhook handling,…
- browser-toolsSecurity
OrchestKit security wrapper for browser automation. Adds URL blocklisting, rate limiting, robots.txt enforcement, and ethical scraping guardrails on top of the upstream agent-browser skill. Use when automating…
- dolt-mcp-vcsAds
Dolt and DoltHub-aware workflow for the beads (bd) task tracker. Diagnoses why bead work is not visible on DoltHub (no Dolt remote configured), applies the bd dolt remote — from…
- sales-integrationSales
Connects sales tools with webhooks, Zapier/Make, native integrations, and custom API pipelines — CRM sync, event triggers, data mapping, and error handling. Use when CRM data isn't syncing from…
- sales-sendgridSales
SendGrid platform help — transactional email via Email API (REST + SMTP), Marketing Campaigns (drag-and-drop editor, automations, A/B testing, signup forms, segmentation), Email Validation API, Dynamic Templates…
- sales-transactional-emailSales
Transactional and triggered email delivery — order confirmations, password resets, welcome emails, receipts, shipping notifications, account alerts. Covers provider selection, template design, deliverability, API…
- testing-e2eEngineering
End-to-end testing patterns with Playwright — page objects, AI agent testing, visual regression, accessibility testing with axe-core, and CI integration. Use when writing E2E tests, setting up Playwright,…
- always-on-agent-inputsEngineering
How to design contextual inputs for an always-on AI agent with episodic memory. Covers what data to feed the agent, how to structure observations and triggers, ambient context capture (screen, audio, calendar),…
- build-bash-scriptTools
Scaffolds a standalone Bash 4.0+ script — a single-file CLI tool, glue automation, or ops utility — with explicit shebang, `set -euo pipefail`, header comment, `readonly` constants, `die` helper, `local` variables,…
- build-python-scriptEngineering
Scaffolds a standalone Python 3 script — a single-file CLI tool, automation helper, or data-wrangling utility — with shebang, module docstring, `main(argv) -> int`, `__main__` guard via `sys.exit(main())`,…
- email-sequence-designerGeneral
Use when the user asks to "design a welcome flow", "set up an abandoned-cart sequence", "build a light re-engagement branch inside a lifecycle flow", or "plan a cold-outbound…
- mock-data-contractProduct
Use WHEN a prototype, frontend handoff, or backend integration needs realistic mock data TO create schema-tied mock contracts and scenario fixtures before frontend implementation. Triggers: ''mock data…
- multimodal-llmGeneral
Vision, audio, video generation, and multimodal LLM integration patterns. Use when processing images, transcribing audio, generating speech, generating AI video (Kling v3, Sora 2, Veo 3.1 std/lite/fast, Runway…
- sales-grainSales
Grain AI meeting recorder platform help — REST API for transcripts, recordings, tags, action items, and video uploads (Business+), MCP Server for Claude/ChatGPT/Cursor with built-in SPICED/MEDDICC prompts, Zapier…
- sales-peerlistSales
Peerlist platform help — professional network for tech builders with weekly Launchpad, portfolio profiles, Scroll feed, and job board. Covers Launchpad submissions (free, weekly Monday launches, all projects…
- sales-trendheroSales
trendHERO platform help — Instagram influencer analytics (95M+ profiles, 20+ filters), Account Quality Score (AQS 1-100, fake follower detection), Audience Analysis, Daily Tracking, Ads Database (10M+ posts),…
- vibe-coding-background-agentContent
Build background AI agents that run alongside developers during vibe coding sessions, proactively helping without being asked. Covers file watcher architecture, event queue design, LLM router for triage, action…
- duplicate-rule-person-account-edge-casesGeneral
When and how to author Duplicate Rules and Matching Rules in B2C / Person Account orgs without breaking lead conversion, cross-object matching, or PII hygiene. Covers PA's dual-record (001/003) shape,…
- github-operationsGeneral
GitHub CLI operations for issues, PRs, milestones, and Projects v2. Covers gh commands, REST API patterns, and automation scripts. Use when managing GitHub issues, PRs, milestones, or Projects with gh.
- llm-integrationEngineering
LLM integration patterns for function calling, streaming responses, local inference with Ollama, and fine-tuning customization. Use when implementing tool use, SSE streaming, local model deployment, LoRA/QLoRA…
- sales-customerioSales
Customer.io platform help — customer engagement and marketing automation for behavior-based multi-channel messaging (email, SMS, push, in-app, WhatsApp). Use when automations aren't triggering on the right…
- storybook-mcp-integrationContent
Storybook MCP server integration for component-aware AI development. Covers 6 tools across 3 toolsets (dev, docs, testing): component discovery via list-all-documentation/get-documentation, story previews via…
- storybook-testingEngineering
Storybook 10 testing patterns with Vitest integration, ESM-only distribution, CSF3 typesafe factories, play() interaction tests, Chromatic TurboSnap visual regression, module automocking, accessibility addon testing,…
- a-normative-extension-for-the-bdi-agentGeneral
Apply normative BDI reasoning to agents that must detect norms, choose which commitments to internalize, and resolve conflicts by comparing consequences. Use when obligations, prohibitions, or policies collide in…
- audit-contractSecurity
Adversarial smart contract security audit. Auto-selects 5-7 specialist agents based on contract features (from a roster of 12). Attacks from every relevant angle: SWC registry, signatures, reentrancy, state machine,…
- gradientSecurity
Use when the user asks to push usage counts into Gradient MSP Synthesize for billing reconciliation, see which accounts' counts drifted since the last push, confirm a dispatched alert became a PSA ticket, find…
- lowcoderTools
Crea aplicaciones Lowcoder (low-code platform) desde código usando el SDK @aorizondo/lowcoder-agent-sdk-core o el MCP server @aorizondo/lowcoder-mcp-server. Usa esto cuando el usuario pida crear, modificar, listar o…
- process-flow-as-is-to-beSales
Documenting As-Is and To-Be business processes for a Salesforce project as swim-lane diagrams with one lane per actor (user, system, integration, customer), explicit decision points, parallel paths,…
- qa-automation-specialistEngineering
Production validation specialist for post-deployment smoke tests, SEO audits, visual regression, and analytics verification. Validates that deployed features meet acceptance criteria in the real environment, not just…
- sales-adrollSales
AdRoll platform help — retargeting, display ads, social ads, CTV, native ads, DOOH, email retargeting, audience segmentation, cross-channel campaigns, Shopify/BigCommerce/WooCommerce integration, RollWorks ABM,…
- sales-airmailSales
Airmail platform help — Apple-exclusive email client with customizable swipe actions, multi-step Custom Actions, Smart Inbox, Send Later, snooze, AppleScript automation, Siri Shortcuts, Objective-C plugin framework,…
- sales-brevoSales
Brevo platform help — email/SMS/WhatsApp campaigns, marketing automation (journeys), transactional messaging, Sales CRM (deals, pipelines), Conversations (live chat, chatbot), Loyalty programs, push notifications,…
- sales-celigoSales
Celigo platform help — mid-market iPaaS, 1000+ connectors, AI-powered error management, endpoint+flow pricing, NetSuite depth, API Management, B2B/EDI, Embedded iPaaS, Celigo Ora AI agent. Use when integration errors…
- sales-constantcontactSales
Constant Contact platform help — email marketing with event management, drag-and-drop campaigns, basic automation, social posting, SMS (US), landing pages, and V3 REST API. Use when Constant Contact emails are…
- sales-fastmailSales
Fastmail platform help — independent privacy-respecting email with full JMAP API, custom domains, Masked Email aliases, calendar/contacts/files, OAuth 2.0, IMAP/SMTP/CardDAV/CalDAV/WebDAV, CORS-enabled, community MCP…
- sales-frontSales
Front platform help — AI-powered customer operations platform with shared inbox, omnichannel support (email, SMS, chat, social, WhatsApp), Autopilot AI resolution, Copilot agent assistant, Smart QA/CSAT, ticketing,…
- sales-getwaitlistSales
GetWaitlist platform help — developer-friendly pre-launch waitlist + referral widget (getwaitlist.com): priority queue, referral leaderboard, automatic emails, REST API (api.getwaitlist.com/api/v1), and…
Frequently asked questions
Which extension type should I use for X?
Are Claude Code extensions sandboxed?
Can I disable extensions per-project?
./.claude/settings.json can override or disable globally-installed hooks. For skills, you can keep them in your global ~/.claude/skills/ directory; Claude will only invoke them when the model judges the task relevant, so unused skills don't fire.