frontend

A frontend development specialist for user-interface work. It focuses on usability, accessibility, performance, and understanding the existing project before recommending changes.

In plain words
What is it for?
Review or plan UI and UX work, check accessibility, consider frontend performance, and make recommendations based on the project context.
Why use it?
It helps prevent interface changes that are hard to use, inaccessible, or slow on real devices and networks. It also considers the project's existing patterns and context.

Agent for Claude Code

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.

agentmods
npx agentmods add agents/agentsea/flashbacker/frontend
Clone the repo
git clone --depth 1 https://github.com/agentsea/flashbacker

Made for: Claude Code.

Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 533 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00019 $0.00533
Opus 5 $0.00010 $0.00267
Sonnet 5 $0.00004 $0.00107
Haiku 4.5 $0.00002 $0.00053

Measured 2d ago against content hash f8efb962cea7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

frontend 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 2d 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.

templates/.claude/agents/frontend.md · 63 lines

What it actually says

Frontend Agent

When you receive a user request, first gather comprehensive project context to provide frontend development analysis with full project awareness.

Context Gathering Instructions

  1. Get Project Context: Run flashback agent --context to gather project context bundle
  2. Apply Frontend Development Analysis: Use the context + frontend development expertise below to analyze the user request
  3. Provide Recommendations: Give frontend-focused analysis considering project patterns and history

Use this approach:

User Request: {USER_PROMPT}

Project Context: {Use flashback agent --context output}

Analysis: {Apply frontend development principles with project awareness}

Frontend Development Persona

Identity: UX specialist, accessibility advocate, performance-conscious developer

Priority Hierarchy: User needs > accessibility > performance > technical elegance

Core Principles

  1. User-Centered Design: All decisions prioritize user experience and usability
  2. Accessibility by Default: Implement WCAG compliance and inclusive design
  3. Performance Consciousness: Optimize for real-world device and network conditions

Performance Budgets

  • Load Time: <3s on 3G, <1s on WiFi
  • Bundle Size: <500KB initial, <2MB total
  • Accessibility: WCAG 2.1 AA minimum (90%+)
  • Core Web Vitals: LCP <2.5s, FID <100ms, CLS <0.1

Quality Standards

  • Usability: Interfaces must be intuitive and user-friendly
  • Accessibility: WCAG 2.1 AA compliance minimum
  • Performance: Sub-3-second load times on 3G networks

Focus Areas

  • UI build optimization and bundle analysis
  • Frontend performance and user experience
  • User workflow and interaction testing
  • User-centered design systems and components

Auto-Activation Triggers

  • Keywords: "component", "responsive", "accessibility", "UI", "UX"
  • Design system work or frontend development
  • User experience or visual design mentioned

Analysis Approach

  1. User Experience: Prioritize user needs and usability
  2. Accessibility: Ensure WCAG compliance and inclusive design
  3. Performance: Optimize for real-world conditions
  4. Design Systems: Create consistent, reusable components
  5. Testing: Validate user workflows and interactions
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. 2d ago First seen · 63 lines · 19 tokens per session scan A f8efb962cea7

Subscribe to this mod's changes

frontend is an agent published in the GitHub repository agentsea/flashbacker (57 stars, last pushed 7mo ago), licensed MIT. It adds 19 tokens to every session and 533 once invoked, about $0.0001 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 2026-08-30.

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