Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add mickeyyaya/refactoring-skills --skill language-specific-idiomsgit clone --depth 1 https://github.com/mickeyyaya/refactoring-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/mickeyyaya/refactoring-skills/language-specific-idioms)<a href="https://agentmods.dev/skills/mickeyyaya/refactoring-skills/language-specific-idioms"><img src="https://agentmods.dev/badge/skills/mickeyyaya/refactoring-skills/language-specific-idioms/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/mickeyyaya/refactoring-skills/language-specific-idioms"><img src="https://agentmods.dev/badge/skills/mickeyyaya/refactoring-skills/language-specific-idioms.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00059 | $0.03014 |
| Opus 5 | $0.00030 | $0.01507 |
| Sonnet 5 | $0.00012 | $0.00603 |
| Haiku 4.5 | $0.00006 | $0.00301 |
Grade A, and why
language-specific-idioms scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 329 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Language-Specific Idioms for Code Review
Overview
Every language has a "grain" — idiomatic patterns aligned with its type system, memory model, and stdlib. Code fighting the grain is harder to read, error-prone, and often slower.
When to use: Reviewing PRs where authors may not know the language idioms, onboarding contributors, or cross-language teams.
Quick Reference
| Language | Core Idiom | Top Red Flag |
|---|---|---|
| TypeScript/JS | Destructuring, optional chaining, readonly types |
var, any, == instead of === |
| Python | Comprehensions, context managers, generators, type hints | C-style for loop, mutable default args, bare except |
| Java | Optional, streams, records, try-with-resources |
null returns, raw types, checked exception abuse |
| Go | Error returns, interfaces, goroutines+channels, defer |
panic for control flow, interface pollution |
| Rust | Ownership, Result/Option chaining (?), iterators |
unwrap() everywhere, defensive clone() |
| C++ | RAII, smart pointers, const correctness, move semantics |
Raw new/delete, C-style casts, void* |
TypeScript / JavaScript
Idiomatic Patterns
- Destructuring + optional chaining (
?.) + nullish coalescing (??) - Array methods over loops;
async/awaitover raw Promises readonly/as constfor immutability;const/letonly (nevervar)
// BEFORE — verbose, var-scoped, manual null check
function getCity(user) {
var city = null;
if (user && user.address && user.address.city) { city = user.address.city; }
return city || 'Unknown';
}
// AFTER — destructuring + optional chaining + nullish coalescing
function getCity({ address }: User): string {
return address?.city ?? 'Unknown';
}
Anti-Idioms
| Anti-Idiom | Idiomatic Replacement |
|---|---|
var x |
const x or let x |
param: any |
Specific type, union, or generic |
a == b |
a === b |
Foo.prototype.bar = ... |
class Foo { bar() {} } |
new Promise(...) wrapping async |
async function directly |
arr.forEach(async ...) |
await Promise.all(arr.map(async ...)) |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago First seen · 329 lines · 59 tokens per session scan A ee5635c62f24
language-specific-idioms is a skill published in the GitHub repository mickeyyaya/refactoring-skills (6 stars, last pushed 5mo ago), licensed MIT. It adds 59 tokens to every session and 3,014 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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