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+.

Download and run open models such as Gemma locally with one command. Provides a REST API and Python/JS libraries, and ollama launch can point Claude Code, Codex and other agents at local models.

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.

Guides the agent through writing or improving a skill: clarify intent, draft SKILL.md, run scored evals with and without the skill, then tune the description so it triggers accurately. Official Anthropic skill.

Open-source browser agent project. Its browser-use CLI lets Claude Code, Codex and other agents drive your logged-in local Chrome with Python snippets, or connect to a cloud browser; also ships a Python agent library. The cloud browser needs an API key.

Gives agents long-term memory across sessions with a local knowledge graph of entities, relations and observations, stored in a local JSONL file you can query and edit. Official MCP reference implementation.

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.

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.

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 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.

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.

Self-improving agent from Nous Research with built-in memory and a learning loop that turns experience into skills. Works with any model provider; the hermes command has a terminal UI, and a gateway connects it to Telegram, Slack and more and runs scheduled tasks.

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.

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.

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.

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.

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.

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

Reference for the Claude API and Anthropic SDK: model selection and pricing, streaming, tool use, prompt caching, Managed Agents and more, plus workflows for model migration and prompt audits. Official Anthropic skill.