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Browse reusable Agent Skills, each with a clear purpose and practical guidance.

diagnostics-development

Guide for creating high-quality, user-friendly diagnostics in Biome. Use when creating diagnostics for lint rules, adding helpful advice to error messages, implementing code frame displays, or improving diagnostic quality.

25.42k repo starsObserved in 1 repos
Development

eslint-migrate-options

Guide for implementing ESLint-to-Biome rule option migrators inside `biome migrate eslint`. Use whenever you add or update a Biome lint rule that has an ESLint source rule with configurable options, need to deserialize plugin-specific ESLint options, or need custom migration logic beyond the auto-generated severity mapping.

25.42k repo starsObserved in 1 repos
Development

formatter-development

Guide for implementing formatting rules using Biome's IR-based formatter infrastructure. Use when implementing formatting for new syntax nodes, handling comments in formatted output, writing or debugging formatter snapshot tests, diagnosing idempotency failures, or comparing Biome's formatting against Prettier for JavaScript, CSS, JSON, HTML, Markdown, or other languages.

25.42k repo starsObserved in 1 repos
Development

lint-rule-development

Step-by-step guide for creating and implementing lint rules in Biome's analyzer. Use when implementing rules like noVar, useConst, or any custom lint/assist rule, adding code actions to fix diagnostics, implementing semantic analysis for binding references, or adding configurable options to rules.

25.42k repo starsObserved in 1 repos
Development

prettier-compare

Compares code formatting and formatting IR between Biome and Prettier to ensure that Biome's formatting is consistent and correct. Use when validating formatter changes, debugging formatting differences, or comparing output for JavaScript, TypeScript, CSS, or other languages.

25.42k repo starsObserved in 1 repos
Testing & Quality

pull-request

Guide for creating proper pull requests for the Biome project. Use when opening a PR, writing a PR description, choosing the correct target branch, or filling out the PR template. Trigger when creating PRs, writing PR summaries, or preparing code for review.

25.42k repo starsObserved in 1 repos
Development

testing-codegen

Guide for testing workflows and code generation commands in Biome. Use when running snapshot tests for lint rules, managing insta snapshots, or regenerating analyzer/parser/formatter code after changes.

25.42k repo starsObserved in 1 repos
Testing & Quality

minimize-reproducer

Use this when you need to minimize a complex or bloated JavaScript test case (e.g., from a fuzzer or external report) into a minimal, readable reproduction for debugging V8 issues.

25.12k repo starsObserved in 1 repos
Testing & Quality

v8-regression-testing

Use this skill when designing, writing, or minimizing regression tests (e.g., mjsunit) for V8 bug fixes

25.12k repo starsObserved in 1 repos
Testing & Quality

v8-security-triaging

Guides the initial analysis and impact assessment of a V8 security report, strictly excluding implementation or fixing.

25.12k repo starsObserved in 1 repos
Testing & Quality