biome: Skill for Claude Code

Promote Lint Rules

Use the batch promotion task instead of invoking just move-rule repeatedly.

Build the Manifest

1. Read the complete requirements. For a GitHub issue, read both its body and comments.
2. Verify every listed current rule exists under a crates/biome_*_analyze/src/lint/nursery/ directory.
3. Resolve incomplete or malformed requirements before editing. Do not infer missing group, recommendation, severity, or rename decisions from neighboring rows.
4. Create a temporary JSON file outside the repository, such as /tmp/biome-rule-promotions.json.

The top-level object maps each current lower-camel-case rule name to its final stable metadata:

{
  "noCurrentRule": {
    "group": "correctness",
    "recommended": true,
    "severity": "error",
    "newName": "noRenamedRule"
  },
  "useAnotherRule": {
    "group": "style",
    "recommended": false
  }
}

Fields:

• group is required and must be a11y, complexity, correctness, performance, security, style, or suspicious.
• recommended is optional. Include it when the requirements specify the final recommendation status; both true and false are meaningful.
• severity is optional. Accepted values are info, warn, and error. Include it when the requirements specify a new final severity.
• newName is optional. Omit it when the rule keeps its current name.

Use current names as object keys, even when newName is present. A rule implemented by multiple analyzers, such as matching JavaScript and HTML rules, needs only one entry.

Apply the Plan

Run the task once:

just promote-rules /tmp/biome-rule-promotions.json

The task validates the complete manifest before moving files. It updates declarations, diagnostic categories, fixture option files, rule-option modules, and the migration rename table as applicable. It does not regenerate derived files or snapshots.

Inspect the move before generation:

git status --short
git diff --stat