Tools

Font toolkit: pyftsubset subsets fonts to the characters you use and outputs WOFF2 to shrink web fonts, and ttx converts fonts to editable XML for inspection and edits. Needs Python 3.11+ and the woff extra for WOFF2; check the license before subsetting commercial fonts.

CLI and TypeScript runtime for discovering and calling MCP servers from the terminal and scripts: list tool signatures and call tools directly, or generate a standalone CLI or typed client from a server. Auto-imports existing MCP configs from Claude Code, Codex and others.

Reads any website's design system in a headless browser and exports DTCG design tokens, Tailwind config, Figma variables and a brand guide in one command, scoring contrast and cross-page consistency. Also an MCP server or Claude Code plugin. Needs Node.js and Chromium or Chrome.

Empirical social science skills from Stanford REAP and CoPaper.AI, bundling 77 in-house and third-party collections: topic selection, literature reviews, DID/RD/IV identification, regression tables in Python, Stata or R, robustness audits and paper writing. Stata flows need Stata installed.

Runs Google Lighthouse across an entire site (sampling similar pages smartly) and summarizes SEO, performance and accessibility scores page by page in a local web UI; unlighthouse-ci writes reports directly for agents to read. Great for site-wide SEO checkups. Needs Node.js 22.18+.

Read-only mirror of the community plugin marketplace maintained by Anthropic, with 2,000+ community plugins that passed submission review and automated security scans, for Claude Code and Claude Cowork.

Design token build tool: define colors, font sizes, spacing and other design specs in one JSON source, then style-dictionary build generates CSS, SCSS, iOS, Android and other platform code, keeping the design system and implementations in sync. Needs Node.js and a config.json.

Draws bar charts, histograms, line charts, scatter plots and box plots in the terminal from CSV/TSV on stdin, so you can glance at data distributions at the end of a shell pipeline. The command is uplot.

Plain-text double-entry accounting: track income, expenses, investments and time, generate balance sheets, income statements and budget reports in one command, with CSV import and JSON output for agent reconciliation and reporting. Converts to and from Beancount.

Cloudflare's official Workers CLI: develop and debug Workers locally, deploy them, manage D1, R2, KV and other resources, and tail live logs. Cloudflare recommends installing it per project; requires a Cloudflare account.

Lets agents manage Firebase projects: read and write Firestore and Realtime Database, manage Auth users, validate security rules, and check Crashlytics crashes and function logs. Maintained by Firebase; sign in to the Firebase CLI first.

Firebase's official CLI: deploy Hosting, Cloud Functions and security rules, run local emulators, read and write databases and import or export users. The same repo also provides the official Firebase MCP server. Requires a Firebase sign-in.

Teaches agents to code against the latest Gemini API and Python/TypeScript SDKs: multi-turn chat, function calling, structured output, and image and speech generation, while avoiding deprecated older models. Maintained by Google's Gemini team.

Gemini API development skills: gemini-api-dev (core API and SDKs), gemini-live-api-dev (real-time bidirectional audio/video streaming) and gemini-omni-flash-api (Omni video generation and editing), filling in APIs released after model training cutoffs. Maintained by Google's Gemini team.

Mixedbread's official semantic grep: search code, text, PDFs and images in natural language, and hook it into Claude Code, Codex and other coding agents in one step to cut token use. Requires a Mixedbread sign-in, and files are synced to its cloud index.

Generates 26+ chart types with AntV, including line, bar, Sankey, word cloud, mind map and pivot table, returning image links. Officially maintained by Ant Group's AntV team; uses a public rendering service by default and can be self-hosted.

Multithreaded lossless PNG optimizer that shrinks screenshots, slices and icons in bulk without quality loss and strips unneeded metadata, handy for design handoff or compressing images before a site launch. Install with Homebrew on macOS.

Create, read and modify xlsx workbooks without Microsoft Excel installed: formulas, formatting and conditional formatting, charts, pivot tables and tables. Runs locally over stdio or as a remote HTTP service.

High-fidelity SVG rendering library and CLI that exports SVG icons and illustrations to PNG at chosen sizes, good for batch asset export. No system dependencies, with pixel-identical output across platforms. No SVG animation support; install with cargo or grab a macOS build from Releases.

Three.js geometry reference with code: parameters for built-in shapes like boxes, spheres, cylinders and tori, building custom meshes from vertices with BufferGeometry, and instanced rendering for large numbers of objects.

Three.js interaction reference with code: raycasting for click detection and object selection, camera controls such as OrbitControls, and mouse and touch input handling for interactive 3D experiences.

Three.js lighting reference with code: ambient, hemisphere, directional, point, spot and area lights with their cost and shadow support, shadow setup, image-based environment lighting and lighting performance tips.

Three.js asset loading reference with code: loading GLTF models, textures, images and HDR environments, coordinating loaders and progress with LoadingManager, and async loading patterns.

Three.js materials reference with code: when to use Basic, Lambert, Phong, Standard, Physical, Toon and other materials, PBR properties such as roughness and metalness, custom ShaderMaterial and material performance.