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.

From Microsoft: converts PDF, Word, Excel, PowerPoint, HTML and other files or URLs to Markdown so agents can read and search them. A single convert_to_markdown tool over STDIO or local HTTP.

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+.

Extracts text and tables from PDFs; merges, splits and rotates pages, adds watermarks, fills forms and OCRs scanned documents. The official Anthropic skill behind Claude's document features; source-available, not open source.

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.

Orchestrates subagents in-session to map the architecture, build a threat model and hunt for vulnerabilities. Every finding is independently verified before it goes in the report, which also comes as SARIF, and optional patch files are left for you to apply. Official Anthropic plugin.

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.

Skills from security firm Trail of Bits: 40+ plugins for code auditing, CodeQL and Semgrep static analysis, differential review, smart-contract and cryptography audits, fuzzing and more. Also installable as a Claude Code or Codex plugin marketplace.

Turns the current folder into a teaching workspace you can resume across conversations: asks your learning goal, gathers reliable sources, builds short HTML lessons and cheat sheets, and tracks progress. Good for self-study and lesson prep; invoke manually (/teach), no API key.

Resolves subscription billing issues: checks customer and subscription state, separates duplicate purchases, team seats and failed payments, restores self-serve before refunding, and drafts the reply. Needs Stripe or similar tools connected; refunds move real money, so review them.

A complete harness for coding agents: dozens of subagents, nearly 300 skills, hooks, rules, memory and continuous learning, plus the AgentShield security scanner. Built mainly for Claude Code, with Codex support.

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.

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.

Ten built-in color and font themes to apply to slides, documents, reports and HTML landing pages, or generate a new theme on demand. 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.

Official MoneyPrinterTurbo skill: give it a topic or script and the agent installs, configures and produces a short video with voiceover, stock footage, subtitles and music; defaults to Chinese vertical MP4. Needs an LLM API key and a free Pexels key; macOS and Windows.

Generates or edits images: photos, illustrations, textures, game sprites, product mockups and transparent assets. A built-in Codex system skill using the image_gen tool, no install needed; with approval it can use a bundled CLI script that needs OPENAI_API_KEY. By OpenAI.

Multi-agent investment research framework where fundamental, sentiment, news and technical analysts, bull and bear researchers, a trader and risk managers debate a stock and produce a report and rating. Covers US, Hong Kong and A-shares. Needs Python and an LLM API key; not investment advice.

OpenAI's open-source general-purpose speech recognition model. The whisper command transcribes many languages, translates foreign speech into English and writes subtitle files. Needs FFmpeg; faster with a GPU.