type-inference

This skill guides developers working on Biome's codebase through essential patterns and pitfalls. It covers AST and syntax node navigation, efficient string extraction without allocation, and handling embedded languages across frameworks like Vue and Svelte. Use it to write cleaner, more maintainable code and avoid costly mistakes when extending Biome's parser, analyzer, and formatter.

This skill establishes documentation standards for Biome developers writing comments and rustdoc in the codebase. It distinguishes three comment types—module docs for explanation, item docs for reference, and inline comments for rationale—and teaches which patterns to avoid. The core principle: write for future contributors with no access to your current context, stating how code works rather than how it came to be.

This skill teaches you how to add parsing support for new languages to Biome by authoring grammars in ungrammar format, implementing lexers and token sources, and writing parse rules with robust error recovery. It covers list parsing patterns, conditional syntax handling, and testing workflows for the Biome codebase.

Biome integrates into .NET repositories to provide combined formatting, linting, and import organization across JavaScript, TypeScript, CSS, JSON, GraphQL, and HTML. The skill handles ownership decisions between Biome and existing tools like ESLint or Prettier, generates configuration, and establishes repeatable commands for CI and local development. It guides migration strategies and validates that your build and test flows remain stable after changes.

This skill guides you through building new lint rules and assist actions for Biome. It covers rule scaffolding across multiple languages, implementation patterns with semantic analysis, code action setup, and the three-pillar diagnostic framework required for all rules. Use it when adding custom rules like noVar or useConst to Biome's codebase.

This skill covers seven Rust design patterns applied to RTK's CLI filter architecture, from type-safe wrappers and configuration builders to stateful parsers and resource management. Each pattern includes practical examples showing when to use it, when to skip it, and how it fits RTK's single-threaded, zero-overhead design philosophy.