Use Biome in .NET repositories that ship Node-based frontend assets and want a fast combined formatter-linter-import organizer for JavaScript, TypeScript, CSS, JSON, GraphQL, or HTML. USE FOR: biome.json or @biomejs/biome setup; fast frontend formatting and linting; replacing overlapping frontend style tools deliberately. DO NOT USE FOR: ESLint-only plugin coverage; runtime site audits such as headers, accessibility, or browser behavior. INVOKES: inspect the repository context, edit targeted fil
SkillScore77Maintained
Automatic
◆Frontend / UI pack
Last verified 8/19/2026
What it changes
Passed 14 of 18 test cases with the skill, and 5 of 18 without it.
Without skill27%
With skill77%
Checks it passed that the model alone missed
Adds biome check . command to package.json scripts
Outlines the plan, execute, review, fix, and update loop stages
Adds biome check . --write command for local formatting and fixing
and 12 more in the full report
12 fixed5 passed either way4 still failing1 broke
Pass-rate lift
+50 pp
Tokens
+22%
Agent turns
0%
Response time
-43%
Model gemini-3.6-flashMeasured 8/19/2026v317 of 22 cases passed with skill · 18 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 12 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 12
Prompt
What rule was added in CLI 2.5.8 to validate CSS property initialization syntax during linter checks? Provide your answer using status, plan, actions_taken, verification, and remaining.
What was checked, without and with the skill
Checked
Without skill
With skill
Identifies noInvalidPropertyInitValue as the new CSS property initialization rule
Missed
Passed
Structures the response with required keys: status, plan, actions_taken, verification, remaining
Passed
Passed
case-21 · gemini-3.6-flash · 8/19/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md104 linessingle file
Biome for Frontend Assets in .NET Repositories
Trigger On
the repo has biome.json, @biomejs/biome, or the user asks for a faster all-in-one frontend formatter-linter stack
the repo wants one tool for formatting, linting, and import organization across JS, TS, CSS, JSON, GraphQL, or HTML
the team is comparing Biome against ESLint plus Prettier or wants to simplify the current stack
Do Not Use For
repos that rely on ESLint plugins or framework-specific rules Biome does not cover yet
runtime site audits such as headers, accessibility, and SEO; route that to webhint
cases where a dedicated CSS or HTML tool is still the deliberate owner and no migration is requested
Inputs
the nearest AGENTS.md
package.json
biome.json or biome.jsonc
current ownership across ESLint, Prettier, Stylelint, and import ordering
Workflow
Decide ownership first:
Biome as the main formatter and linter
Biome only for formatting
Biome in coexistence with ESLint for plugin gaps
Prefer a repo-local pinned install so CI and developer machines use the same version.
Generate biome.json only after confirming what the repo wants Biome to own.
Add repeatable scripts to package.json, for example:
biome check .
biome check . --write
Keep file ownership explicit:
Biome can own formatting, linting, and import sorting
webhint still owns site-runtime audits
ESLint may stay for plugin-heavy cases the repo intentionally keeps
Start migrations with check and bounded folders before flipping the whole repo to --write.
Re-run the frontend build and tests after broad formatting or lint-fix passes.
Use the free built-in .NET SDK analyzers and analysis levels with gradual Roslyn warning promotion. USE FOR: the repo wants first-party .NET analyzers; CI should fail on analyzer warnings; the team needs AnalysisLevel or AnalysisMode guidance. DO NOT USE FOR: third-party analyzer selection by itself; formatting-only work. INVOKES: inspect the repository context, edit targeted files, and run relevant build, test, lint, or validation commands when changes are made.