Tools

Command-line audio and video downloader supporting thousands of sites: pick formats and quality, grab subtitles and metadata, and merge or transcode with FFmpeg. The actively maintained fork of youtube-dl.

Converts PDF, Word, Excel, PowerPoint, HTML, images, audio and more into Markdown that keeps headings, lists and tables, ready for LLMs to read and analyze. Maintained by Microsoft; requires Python 3.10+.

Anthropic's document skills, the implementation behind Claude's file features: create, edit and analyze Word, Excel, PowerPoint and PDF files, including tracked changes, comments, formulas and form filling. Source-available, not under an open-source license.

Controls your local Chrome over CDP to navigate, click, type, take screenshots and scrape data, reusing logged-in sessions. Official browser-use skill; install the browser-use CLI with uv first.

Flags and rewrites AI-sounding text using 25 patterns drawn from Wikipedia's 'Signs of AI writing', keeping the meaning without inventing facts. Give it a writing sample to match your own voice.

Marketing skills for technical marketers and founders: 50 skills covering conversion optimization, copywriting, SEO and AI search, paid ads, email and cold outreach, pricing, customer research and launch strategy, all sharing one product-marketing context.

166 research skills maintained by K-Dense (formerly Claude Scientific Skills), spanning bioinformatics, cheminformatics, clinical research, materials and physics, including unified access to 78 public databases such as PubChem and UniProt. Works with Claude Code, Codex and Cursor.

In-process analytical SQL database. Its CLI queries CSV, Parquet and JSON files directly with SQL, no import or server needed, so agents can sample and aggregate large files. Officially maintained.

Anthropic's role-based skill collection covering sales, finance, legal, HR, support, marketing, product, design, operations and data analysis: over a hundred skills you can install one at a time. Works best with CRM, data warehouse and other connectors.

Anthropic's knowledge-work plugin marketplace, bundling skills, commands and connectors by role: sales, support, product, marketing, legal, finance, HR, data and more, plus many partner plugins. Built mainly for Cowork; also works in Claude Code.

Google's open-source database MCP server with ready-made query and SQL tools for dozens of sources, including PostgreSQL, MySQL, BigQuery, Spanner and MongoDB. Define controlled custom queries in tools.yaml.

Lets agents call the Stripe API to manage customers, payments, subscriptions, invoices and refunds, and search Stripe docs and support articles. Maintained by Stripe; the remote server uses OAuth, or run it locally via npx with a secret key.

Before you build, the agent grills you on your plan or design, offering a recommended answer each round, until every decision branch is resolved. It calls the grilling skill from the same repo, so install both.

Before writing code, asks questions one at a time to clarify intent, constraints and success criteria, turning a vague idea into a reviewable design; implementation starts only after you approve it. A core Superpowers skill.

Creates, reads and edits Word documents: tables of contents, page numbers and letterheads, tracked changes, comments and find-and-replace, while preserving existing formatting. The official Anthropic skill behind Claude's document features; source-available, not open source.

Builds multi-component web pages that need state or routing with React, Tailwind CSS and shadcn/ui, using bundled init and build scripts, then packs them into a single HTML file for a claude.ai Artifact. Official Anthropic skill.

Develops a design philosophy first, then draws posters, illustrations and other static visuals in code, exporting PNG or PDF. Emphasizes original work rather than copying existing artists. Official Anthropic skill.

Makes GIFs that follow Slack's recommended size, frame rate, color and length for emoji (128x128) and message GIFs (480x480), with animation tips and tools to assemble and validate them. Built on Python and Pillow. Official Anthropic skill.

Creates, reads and edits PowerPoint decks: applies templates and layouts, handles speaker notes and comments, and merges or splits slides. The official Anthropic skill behind Claude's document features; source-available, not open source.

Guides users through co-writing proposals, technical specs and decision docs in three stages: gather context, refine section by section, then test with a fresh session that lacks the context to catch what readers won't understand. Official Anthropic skill.

Writes internal communications in familiar company formats: 3P updates, leadership reports, project status updates, company newsletters, FAQs and incident reports. Official Anthropic skill.

Creates, edits and analyzes Excel spreadsheets: formulas, formatting, charts and data cleaning, plus conversion between CSV, TSV and other tabular formats. The official Anthropic skill behind Claude's document features; source-available, not open source.

After giving advice, a draft or a data analysis, adds 2-3 targeted follow-up questions that prompt the user to check key facts, test the reasoning and fill in missing context. Fires at most once per conversation. Official Anthropic skill.

GitHub's official spec-driven development toolkit: the specify CLI sets up spec, plan and task workflows for Copilot, Claude Code, Codex and other agents so the spec comes before the code, plus bug-fix and idea-evaluation flows. Needs Python 3.11+ and uv.