Code Style: Exist, Reuse, Mirror, Symmetry

What it does

• Gives Claude seven ordered principles; when two conflict, the earlier one wins.
• ① Prove the code needs to exist: drop one-implementation abstractions, single-caller config points, unreachable branches, and speculative scaffolding. Trust-boundary validation, data-loss-preventing error handling, security controls, and accessibility always outrank this rule.
• ② ③ Reuse code and patterns: check for a reusable or generalizable method before writing a helper; replicate the closest analogous feature's decomposition, control flow, and guard clauses instead of inventing a new pattern.
• ④ Mirror surroundings exactly: match brace style, comment style, naming, blank-line spacing, code density, and level of detail after reading nearby code.
• ⑤ Maintain symmetry: when adding fooB() next to fooA(), align naming, parameter order, and structure — extending to route paths, config keys, event names, env vars, CLI flags, and file naming. Renaming the old name is the default unless it's a published contract you can't update.
• ⑥ ⑦ Ordering and comments: insert methods, switch cases, and fields where the existing grouping or business lifecycle says they belong, and default to no comment unless a load-bearing constraint can't be expressed in code.

Who it's for

• Engineers shipping AI-written changes into large or legacy codebases where style drift creates review noise
• Anyone tired of AI-generated over-abstraction, unnecessary options, and chatty comments
• Tech leads who want their review standards applied to AI output too

Examples

1. Adding POST /teams next to an existing POST /users handler — the new handler copies the old one's guard clauses, error handling, and naming.
2. "Make this configurable" when there's only one caller — the skill pushes toward inlining rather than adding a config point.
3. Adding exportXlsx() beside exportCsv() — function names, parameter order, file naming, and CLI flags are brought into symmetry, renaming the older name when it isn't a public contract.

Read the instructions in this file and follow them to help me:
https://raw.githubusercontent.com/tobihagemann/turbo/HEAD/claude/skills/code-style/SKILL.md

What I want: (describe your task here)

Install the skill I found on Claude Skill Mart.
Copy the claude/skills/code-style folder from the GitHub repo tobihagemann/turbo into my ~/.claude/skills/code-style/.
When it's done, tell me in one line what this skill can do.