# Fullstack Guardian

Builds security-focused full-stack web applications by implementing integrated frontend...

- Repository: https://github.com/Jeffallan/claude-skills (12164 stars)
- Category: Design
- License: MIT
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add Jeffallan/claude-skills --skill fullstack-guardian -g -a claude-code -y`
Codex: `npx skills add Jeffallan/claude-skills --skill fullstack-guardian -g -a codex -y`
Cursor: `npx skills add Jeffallan/claude-skills --skill fullstack-guardian -g -a cursor -y`
Gemini CLI: `npx skills add Jeffallan/claude-skills --skill fullstack-guardian -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add Jeffallan/claude-skills`

## Description

Builds security-focused full-stack web applications by implementing integrated frontend and backend components with layered security at every level. Covers the complete stack from database to UI, enforcing auth, input validation, output encoding, and parameterized queries across all layers. Use when implementing features across frontend and backend, building REST APIs with corresponding UI, connecting frontend components to backend endpoints, creating end-to-end data flows from database to UI, or implementing CRUD operations with UI forms. Distinct from frontend-only, backend-only, or API-only skills in that it simultaneously addresses all three perspectives, Frontend, Backend, and Security, within a single implementation workflow. Invoke for full-stack feature work, web app development, authenticated API routes with views, microservices, real-time features, monorepo architecture, or technology selection decisions.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Fullstack Guardian

Security-focused full-stack developer implementing features across the entire application stack.

## Core Workflow

1. **Gather requirements** - Understand feature scope and acceptance criteria
2. **Design solution** - Consider all three perspectives (Frontend/Backend/Security)
3. **Write technical design** - Document approach in `specs/{feature}_design.md`
4. **Security checkpoint** - Run through `references/security-checklist.md` before writing any code; confirm auth, authz, validation, and output encoding are addressed
5. **Implement** - Build incrementally, testing each component as you go
6. **Hand off** - Pass to Test Master for QA, DevOps for deployment

## Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When |
|-------|-----------|-----------|
| Design Template | `references/design-template.md` | Starting feature, three-perspective design |
| Security Checklist | `references/security-checklist.md` | Every feature - auth, authz, validation |
| Error Handling | `references/error-handling.md` | Implementing error flows |
| Common Patterns | `references/common-patterns.md` | CRUD, forms, API flows |
| Backend Patterns | `references/backend-patterns.md` | Microservices, queues, observability, Docker |
| Frontend Patterns | `references/frontend-patterns.md` | Real-time, optimization, accessibility, testing |
| Integration Patterns | `references/integration-patterns.md` | Type sharing, deployment, architecture decisions |
| API Design | `references/api-design-standards.md` | REST/GraphQL APIs, versioning, CORS, validation |
| Architecture Decisions | `references/architecture-decisions.md` | Tech selection, monolith vs microservices |
| Deliverables Checklist | `references/deliverables-checklist.md` | Completing features, preparing handoff |

## Constraints

The rest: https://github.com/Jeffallan/claude-skills/blob/HEAD/skills/fullstack-guardian/SKILL.md