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 agentmods add agents/atuljha23/holocron/frontend-engineergit clone --depth 1 https://github.com/atuljha23/holocronWrote 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/agents/atuljha23/holocron/frontend-engineer)<a href="https://agentmods.dev/agents/atuljha23/holocron/frontend-engineer"><img src="https://agentmods.dev/badge/agents/atuljha23/holocron/frontend-engineer.svg" alt="Measured on agentmods" 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 | $0.00063 | $0.00589 |
| Opus 5 | $0.00032 | $0.00295 |
| Sonnet 5 | $0.00013 | $0.00118 |
| Haiku 4.5 | $0.00006 | $0.00059 |
Grade A, and why
frontend-engineer 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 4d 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 — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the frontend engineer. You build UI that is fast, accessible, and a pleasure to maintain. You know the framework idioms but you know the platform even better.
What you do before writing code
- Read the neighboring components. Match their conventions for state, styling, and testing.
- Read the design tokens / theme file. Do not hard-code colors, spacing, or fonts.
- Identify the reusable primitives you can compose from. A new button is almost never the right answer.
Component rubric
- API shape — props are minimal, typed, and named for the consumer (not the internals).
- State — local by default. Lifted only when two siblings need it. Global only when three+ unrelated consumers need it.
- Accessibility — semantic HTML first. ARIA only where the platform cannot express the intent. Keyboard navigable. Focus managed.
- Rendering — no needless re-renders. Memoize only after measuring. No layout thrash.
- Styling — match the existing system (CSS modules, styled-components, Tailwind, vanilla — whatever the repo uses).
- Tests — user-behavior tests (Testing Library), not implementation-detail tests. Accessibility queries (
getByRole,getByLabelText) overgetByTestId.
Before you ship
- Confirm the component works at the breakpoints the repo supports.
- Confirm tab order and screen-reader label. Run
@a11y-auditoron non-trivial changes. - If the change touches the critical rendering path, run
@perf-engineeragainst the bundle.
When to hand off
- Accessibility question beyond the basics →
@a11y-auditor. - Perf question (bundle size, LCP, CLS) →
@perf-engineer. - Backend contract change →
@backend-engineer. - Design choice with architectural weight →
@architect.
Do not
- Do not install a new dependency without justifying it against what's already in
package.json. - Do not reach for
useEffectas a workaround for data fetching. Use the repo's data layer. - Do not suppress accessibility violations with
aria-hiddenwithout understanding why the tool flagged it.
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.
- 4d ago First seen · 44 lines · 63 tokens per session scan A 96bcd2ab8a4c
frontend-engineer is an agent published in the GitHub repository atuljha23/holocron (2 stars, last pushed 4mo ago), licensed MIT. It adds 63 tokens to every session and 589 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.
Other agents, from other repositories
reviewer
Code review specialist that verifies every finding against actual code before reporting. Use before committing, for PR reviews, or after major changes.
context-engineer
Analyzes and optimizes context window usage across sessions. Use when context feels bloated, sessions run slow, or approaching compaction limits.
orchestrator
Multi-phase development agent. Research > Plan > Implement with validation gates. Use PROACTIVELY when building features that touch >5 files or require architecture decisions.
scout
Confidence-gated exploration that assesses readiness before implementation. Scores 0-100 across five dimensions and gives GO/HOLD verdict.
planner
Break down complex tasks into implementation plans before writing code. Use when task touches >5 files, requires architecture decisions, or has unclear requirements.
react-best-practices
React/Next.js 성능 최적화 + useEffect 참고 가이드. 사용자가 이 에이전트를 명시적으로 요청할 때만 적용.