Ultracite

A single command, npx ultracite init, wires up your chosen linter and formatter, editor settings, and AI agent rules. You answer a few prompts and the installer writes the files. It even strips out ESLint and Prettier configs that would conflict, so you don't debug duplicate rules later.

Ultracite works with Oxlint plus Oxfmt, Biome, or ESLint plus Prettier and Stylelint. Oxlint is the fastest option, and it runs far quicker than ESLint according to the project. Biome bundles linting and formatting into one Rust binary. The ESLint route is there for teams that rely on its large plugin library.

This is the feature that sets Ultracite apart from a plain linter. init generates context files for Claude Code, GitHub Copilot, Cursor, Gemini, and other agents, so their suggestions match your project's style. It also ships a reusable skill and hooks that reformat code right after an AI edit lands.

ultracite fix corrects formatting and many lint errors that are safe to change, like removing unused imports or switching == to ===. Riskier rewrites wait behind a --unsafe flag, and anything needing developer judgment gets flagged instead of silently changed.

Formatting runs on save in VS Code, Cursor, and Windsurf, and init can also write Zed settings. Every toolchain runs from the command line through ultracite check and ultracite fix, which means the same checks work in any editor and in CI.

One configuration spans every package in a monorepo, doing away with the pile of duplicate config files that usually builds up. Ultracite also hooks into Husky, Lefthook, lint-staged, and pre-commit so staged files stay clean before they reach review.

Setup enables strict null checks in your tsconfig.json files unless they're already on or you've turned them off. The presets add lint rules that catch unsafe typing and suggest fixes, which cuts down on runtime errors early.