Tools

From Callstack: lets coding agents inspect, operate and verify apps on iOS, Android and HarmonyOS simulators and real devices, reading accessibility snapshots, taking screenshots and recordings, and capturing logs and performance data. Ships both a CLI and a built-in MCP server.

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.

Generates hand-drawn-style Excalidraw diagrams (.excalidraw files you can keep editing on excalidraw.com) from text, choosing fan-out, timeline or convergence layouts by how concepts relate. Optional uv and Playwright let the agent render and check layouts; colors live in one file you can restyle.

Classic CLI for reading and writing metadata in hundreds of file types including images, video, audio and PDF, covering EXIF, GPS, IPTC, XMP and camera makers' proprietary tags, with batch editing, stripping and conversion. Requires Perl.

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.

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.

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.

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.

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.

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.

Teaches agents to write video prompts for ByteDance's Seedance 2.0: input limits, @ asset references and camera language, with templates for product ads, short dramas, dance, scenic clips, e-commerce and explainers, in English and Chinese. Prompts only; generate videos with your own account.

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.

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.

Expo's official plugin covering Expo Router navigation, native UI, data fetching and SDK upgrades, plus EAS builds, OTA updates and app store submission. Some service-related skills rely on paid EAS.

Expo's official skills: Expo Router navigation, native-feeling UI, animations, native modules and SDK upgrades, plus EAS build and submit, OTA updates and CI workflows. EAS skills use Expo's paid services.

Hugging Face's official hf CLI: search, download and upload models and datasets, manage repos and storage buckets, and run jobs on Hugging Face's cloud. Output adapts automatically for agents, and hf skills add installs companion skills. Uploads and similar actions need a login.

Guides SwiftUI view building: choosing @State, @Binding, @Observable or @Environment by ownership, wiring TabView, NavigationStack and sheets, async loading with .task, small composed views and previews, plus anti-patterns and a component reference index.

Extracts any website's logo, colors, fonts, spacing, shadows and motion in one command, exporting W3C design tokens, a Tailwind theme, DESIGN.md or a brand guide PDF, plus WCAG contrast checks. Good for competitor and brand audits. Needs Node.js 18+; run dembrandt install-browser first.

Design engineer Jakub Krehel's UI polish skill covering animation, typography, icons, hover states, optical alignment, concentric radii, shadows and hit areas, with quick and full review modes, so agents get the details right when building or reviewing UI. Works on web code; needs Node.js.

NVIDIA's official plugin that finds and installs the right skills from NVIDIA's catalog for your task, spanning CUDA acceleration, NIM inference, NeMo training, RAG blueprints, Omniverse simulation and robotics. Listed in both the Claude and Codex official marketplaces.

NVIDIA's official, verified catalog of hundreds of skills covering CUDA-X libraries, NeMo training, NIM and Dynamo inference, RAG blueprints, Jetson, Omniverse and robotics simulation. The install adds only nvidia-skill-finder, which recommends other skills and installs them once you confirm.

Fast Rust toolkit for tabular data with nearly 80 subcommands for querying, stats, cleaning, validation, joins and format conversion on CSV and Excel. Also offers an MCP server and a Claude Cowork plugin.