fe-developer

fe-developer is an agent for Claude Code from bybren-llc/a-safe-pulse. It costs 11 tokens per session (1,597 once invoked), scanned A, original, MIT.

An agent role for implementing frontend user interfaces from existing project patterns. Frontend work is the part of an application that users see and interact with, and the role is intended for React-style components and pages.

In plain words
What is it for?
Use it to build UI components, pages, and client-side logic after the ticket's acceptance criteria or definition of done are clear.
Why use it?
It sets clear boundaries: the agent must have acceptance criteria before starting, must validate its work, and must not invent requirements or create pull requests.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

Good fit Use it to build UI components, pages, and client-side logic after the ticket's acceptance criteria or definition of done are clear.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/bybren-llc/a-safe-pulse/fe-developer
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/bybren-llc/a-safe-pulse

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 fe-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/bybren-llc/a-safe-pulse/fe-developer/github.svg)](https://agentmods.dev/agents/bybren-llc/a-safe-pulse/fe-developer)
Your own site
<a href="https://agentmods.dev/agents/bybren-llc/a-safe-pulse/fe-developer"><img src="https://agentmods.dev/badge/agents/bybren-llc/a-safe-pulse/fe-developer/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 fe-developer

Your own site · 80×15
<a href="https://agentmods.dev/agents/bybren-llc/a-safe-pulse/fe-developer"><img src="https://agentmods.dev/badge/agents/bybren-llc/a-safe-pulse/fe-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 11 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,597 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 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 5.1 $0.00011 $0.01597
Opus 5 $0.00005 $0.00798
Sonnet 5 $0.00002 $0.00319
Haiku 4.5 $0.00001 $0.00160

Measured 4d ago against content hash c6402e7cb78d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

fe-developer 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.

.claude/agents/fe-developer.md · 240 lines

How it starts

The opening of the file, as written. The whole thing — 240 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Frontend Developer

Role Overview

Implements UI components using patterns from patterns_library/. Focus on execution, not discovery.

Precondition (Stop-the-Line Gate)

MANDATORY CHECK before starting any work:

  • Verify ticket has Acceptance Criteria or Definition of Done
  • If AC/DoD is missing or unclear:
    • STOP - Do not proceed with implementation
    • Route back to BSA/POPM to define AC/DoD
    • You are NOT responsible for inventing AC/DoD
  • Work begins ONLY when AC/DoD exists

Ownership Model

You Own:

  • Code changes (UI components, pages, client logic)
  • Atomic commits in SAFe format: feat(ui): description [ASP-XXX]

You Must:

  • Run iterative validation loop until ALL checks pass
  • Explicitly confirm ALL AC/DoD satisfied before handoff
  • Commit your own work (you own your commits)

You Must NOT:

  • Create PRs (RTE's responsibility)
  • Merge to dev/master (Scott's final authority)
  • Invent AC/DoD (BSA's responsibility)

Available Skills (Auto-Loaded)

The following skills are available and will auto-activate when relevant:

  • frontend-patterns - UI component patterns (DORMANT)
  • pattern-discovery - Pattern library discovery before implementation
  • safe-workflow - Branch naming, commit format, PR workflow

🚀 Quick Start

Your workflow in 4 steps:

  1. Read speccat specs/ASP-XXX-{feature}-spec.md
  2. Find pattern → Check spec for pattern reference, read from docs/archive/harness-upstream/patterns-ui/
  3. Copy & customize → Follow pattern's customization guide
  4. Validate → Run npx tsc --noEmit && npx tsc --noEmit && npm run build

That's it! BSA already did pattern discovery. You just execute.

Success Validation Command

# Full validation before PR
npx tsc --noEmit && npx tsc --noEmit && npm run build && echo "FE SUCCESS" || echo "FE FAILED"

Pattern Execution Workflow (ASP-300)

Read the full file on GitHub · 240 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. 4d ago First seen · 240 lines · 11 tokens per session scan A c6402e7cb78d

Subscribe to this mod's changes

fe-developer is an agent published in the GitHub repository bybren-llc/a-safe-pulse (9 stars, last pushed 5mo ago), licensed MIT. It adds 11 tokens to every session and 1,597 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 2026-09-04.

Related

Other agents, from other repositories

react18-class-surgeon

Class component migration specialist for React 16/17 → 18.3.1. Migrates all three unsafe lifecycle methods with correct semantic replacements (not just UNSAFE prefix). Migrates legacy context to createContext, string refs to React.createRef(), findDOMNode to direct refs, and ReactDOM.render to createRoot. Uses memory…

github/awesome-copilot · 81 tokens

react19-auditor

Deep-scan specialist that identifies every React 19 breaking change and deprecated pattern across the entire codebase. Produces a prioritized migration report at .github/react19-audit.md. Reads everything, touches nothing. Invoked as a subagent by react19-commander.

github/awesome-copilot · 61 tokens

genpage-edit-planner

Plans edits to an existing generative page. Reads the downloaded page artifacts (source, original prompt, config), analyzes the current implementation against the user's edit intent, presents an edit plan via plan mode, and writes genpage-edit-plan.md for the orchestrator to execute. Called by the genpage skill — not…

microsoft/power-platform-skills · 73 tokens

react-portfolio-engineer

React portfolio/gallery sites for creatives: React 18+, Next.js App Router, image optimization.

notque/vexjoy-agent · 25 tokens

nextjs-expert

Next.js framework strategist. Makes decisions about rendering strategies (SSR/SSG/ISR), App Router patterns, data fetching, and performance optimization. Use when designing Next.js applications, choosing rendering methods, or architecting full-stack React apps.

armanzeroeight/fastagent-plugins · 53 tokens

docs-app-builder

Use this agent to build a documentation application as a React app — from a repo's README, docs folder, or code. Trigger on "build a docs site", "documentation app for this project", "turn these docs into a website", "docs portal with navigation", or requests to make existing docs browsable/interactive. Returns a…

aayushostwal/nexus · 97 tokens