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 rungchan2/frontend-skills --skill dayjs-kstgit clone --depth 1 https://github.com/rungchan2/frontend-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/rungchan2/frontend-skills/dayjs-kst)<a href="https://agentmods.dev/skills/rungchan2/frontend-skills/dayjs-kst"><img src="https://agentmods.dev/badge/skills/rungchan2/frontend-skills/dayjs-kst/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/rungchan2/frontend-skills/dayjs-kst"><img src="https://agentmods.dev/badge/skills/rungchan2/frontend-skills/dayjs-kst.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 | $0.00155 | $0.01031 |
| Opus 5 | $0.00077 | $0.00515 |
| Sonnet 5 | $0.00031 | $0.00206 |
| Haiku 4.5 | $0.00015 | $0.00103 |
Grade A, and why
dayjs-kst 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 11d 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 — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Dayjs KST 중앙 setup
한국 서비스에서 반복되는 dayjs 설정을 단 한 번만 하도록 표준 파일을 생성한다.
왜 필요한가
- plugin 등록 누락: 컴포넌트마다
import dayjs from "dayjs"하면dayjs.tz()호출 시 plugin 미등록 에러가 산발적으로 발생한다. - timezone shift:
YYYY-MM-DD같은 date-only 값을 그냥new Date()로 파싱하면 로컬 타임존에 따라 하루씩 밀리는 버그가 잦다.parseDateOnly로 일괄 처리. - 한국어 locale:
dayjs().format("LL")같은 호출이 자동으로 한국어로 나오게.
워크플로우
1. 위치 결정
| 프로젝트 구조 | 파일 위치 |
|---|---|
src/ 구조 |
src/lib/dayjs.ts |
| 루트 직접 | lib/dayjs.ts |
다른 프로젝트들과 일관성 위해 dayjs.ts 파일명 그대로 둔다 (date.ts, date-utils.ts 등으로 바꾸지 않음).
2. 패키지 설치
pnpm add dayjs
3. 파일 생성
assets/dayjs.ts를 결정한 위치에 복사한다.
이미 lib/dayjs.ts가 있다면 → 사용자에게 기존 파일 보여주고 덮어쓸지 / 헬퍼만 추가할지 물어본다.
4. 기존 코드 마이그레이션 안내
스킬 실행 후 사용자에게 다음을 안내한다:
기존 코드에서
import dayjs from "dayjs"를 모두import dayjs from "@/lib/dayjs"로 바꿔야 합니다. 자동 변환을 원하시면 말씀해주세요.
자동 변환 요청 시:
# Next.js (alias가 @/ 인 경우)
grep -rl 'from ["\x27]dayjs["\x27]' src/ app/ components/ hooks/ 2>/dev/null \
| xargs -I{} sed -i '' 's|from "dayjs"|from "@/lib/dayjs"|g; s|from '\''dayjs'\''|from '\''@/lib/dayjs'\''|g' {}
(macOS sed 기준. 작업 전 git status 깨끗한지 확인하고 실행할 것.)
5. 사용 패턴 안내 (CLAUDE.md 추가)
선택적으로 다음 블록을 CLAUDE.md에 추가:
## 날짜 처리 규칙
- 모든 dayjs 호출은 `@/lib/dayjs`에서 import. 직접 `from "dayjs"` 금지.
- 이유: timezone/locale/plugin이 등록된 인스턴스를 보장하기 위함.
- date-only 문자열(YYYY-MM-DD)은 `parseDateOnly()` 사용. `new Date()` 직접 호출 금지.
- 입력 form의 Date + "HH:mm"은 `formatDateTime()` 사용.
산출물
lib/dayjs.ts(또는src/lib/dayjs.ts)package.json에dayjs추가- (선택) 기존 코드의 import 경로 일괄 변환
- (선택) CLAUDE.md에 날짜 규칙 블록
헬퍼 함수 요약
| 함수 | 입력 | 출력 | 용도 |
|---|---|---|---|
parseDateOnly(s) |
"2026-04-30" |
Dayjs | null |
date-only 컬럼 |
formatDateOnly(d) |
Date / Dayjs |
"2026-04-30" |
UI 표시용 |
parseTimestamp(s) |
ISO 문자열 | Dayjs | null |
created_at 등 |
formatDateTime(date, "14:30") |
Date + 시각 | ISO 문자열 (KST) | form 입력 |
extractTime(d) |
날짜값 | "14:30" |
시간만 표시 |
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 11d ago First seen · 84 lines · 155 tokens per session scan A 92c376bf9cd1
dayjs-kst is a skill published in the GitHub repository rungchan2/frontend-skills (2 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 155 tokens to every session and 1,031 once invoked, about $0.0008 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.
Other skills, from other repositories
crowdin-api-client
Use when implementing, refactoring, or reviewing @crowdin/crowdin-api-client usage in any JavaScript or TypeScript project, especially for endpoint selection, request/response typing, pagination, uploads, retries, timeouts, or CrowdinError handling.
code-translator
A tool that rewrites code from one programming language into another, including JavaScript to TypeScript and Python to JavaScript.
i18next
Comprehensive guide for implementing internationalization (i18n) with i18next in JavaScript/TypeScript projects. Use this skill whenever the user asks about i18next setup, configuration, translation functions, pluralization, interpolation, formatting, context, namespaces, TypeScript integration, language detection, or…
no-bare-casts
Writing as in TypeScript or TSX production code, modifying a file that contains a bare as cast, silencing a type error with a cast, encountering as unknown as, or reviewing a cast site.
aws-sst-development
SST v4 (Ion) expert for managing AWS resources as code with the Pulumi-backed framework.
league-akari-shard-development
Use when creating, extending, refactoring, splitting, or reviewing League Akari main or renderer shards, including shard file organization, controller/loader/executor/handler boundaries, naming conventions, renderer TSX usage, platform guards, and public contract compatibility.