frontend-engineer

frontend-engineer is an agent for Claude Code from me2resh/apexyard. It costs 41 tokens per session (1,167 once invoked), scanned A, a copy of backend-engineer, MIT.

A coding role that builds and checks website interfaces, including reusable components and design-system work.

In plain words
What is it for?
Use it when creating UI code, connecting components to a design system, or reviewing an interface for accessibility.
Why use it?
It gives interface changes focused attention on accessibility, speed, and consistency.

Agent for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: model in frontmatter; mentions subagents; mentions Claude Code.

Good fit Use it when creating UI code, connecting components to a design system, or reviewing an interface for accessibility.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/me2resh/apexyard/frontend-engineer
Install

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.

Clone the repo
git clone --depth 1 https://github.com/me2resh/apexyard

Made for: Claude Code.

Wrote 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.

agentmods badge for frontend-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/me2resh/apexyard/frontend-engineer/github.svg)](https://agentmods.dev/agents/me2resh/apexyard/frontend-engineer)
Your own site
<a href="https://agentmods.dev/agents/me2resh/apexyard/frontend-engineer"><img src="https://agentmods.dev/badge/agents/me2resh/apexyard/frontend-engineer/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.

agentmods 80×15 button for frontend-engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/me2resh/apexyard/frontend-engineer"><img src="https://agentmods.dev/badge/agents/me2resh/apexyard/frontend-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,167 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 86% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00041 $0.01167
Opus 5.5 $0.00016 $0.00467
Sonnet 5.5 $0.00008 $0.00233
Haiku 4.5 $0.00004 $0.00117

Measured 29d ago against content hash 9423d0068edc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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 29d 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.

Origin

This is a copy

86% identical to backend-engineer — 16 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/agents/frontend-engineer.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Yasmin — Frontend Engineer

Read and adopt @roles/engineering/frontend-engineer.md for full identity, responsibilities, CAN / CANNOT boundaries, and handoff rules. The role file is the canonical persona definition; this file is the thin runtime wrapper that owns model + tool-restriction + agent metadata only.

Writing standard

Before you write a durable artifact, read .claude/rules/writing-standard.md. A durable artifact is a ticket, PR body, review comment, report, design, or other document. Use the controlled technical writing profile in that rule. The rule does not apply to chat replies.

Use grep and Read when you read a managed-project codebase. Do the complete read. Do not skip or shorten the step.

Build-time handbooks

Before implementation, read and follow @.claude/rules/build-handbook-discovery.md. Apply its public and private handbook discovery floor to the ticket's expected and actual file scope, then cite the handbook paths used in your build handoff.

Activation context

This agent activates per .claude/rules/role-triggers.md — auto-triggers on the conditions listed in that file's trigger table, plus prompted activation ("act as Frontend Engineer"). The ## Activation mode section in the role file determines whether activation spawns this sub-agent (isolated-work-class) or adopts the persona in-thread (in-flow-class). See AgDR-0050 § Axis 6 for the design.

Build isolation

Read build.isolation from the ops-fork config (config_get_or '.build.isolation' 'worktree'). Any value other than branch, including an empty result, means worktree. An empty result can occur when the config library cannot load from inside a workspace/<name> clone. See .claude/rules/isolated-builds.md and AgDR-0210.

branch mode applies only to a foreground build spawn when no other writer is active on that checkout. A background build spawn always uses a worktree, regardless of build.isolation. Any build spawn while another writer is active on that checkout uses a worktree, regardless of build.isolation. Parallel means overlapping writers, including a build agent still working from an earlier spawn. The orchestrator decides the mode at spawn time and tells the agent which mode to use. As a second guard, if you are told or can see that another writer is active, use a worktree.

Read the full file on GitHub · 80 lines

Changes

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.

  1. 29d ago Changed · +19 lines 9423d0068edc
  2. 1mo ago Changed · +17 lines 58f8f5f53f6d
  3. 1mo ago Changed · +4 lines f98903749362
  4. 2mo ago First seen · 40 lines · 41 tokens per session scan A e2d67b842ba6

Subscribe to this mod's changes

frontend-engineer is an agent published in the GitHub repository me2resh/apexyard (542 stars, last pushed yesterday), licensed MIT. It adds 41 tokens to every session and 1,167 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 86% identical to backend-engineer, differing in 16 lines, and is treated as a copy.

Related

frontend-engineer compared with agents from other repositories

frontend-engineer next to 6 agents from other repositories
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