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 skills/saeed-vayghan/gemini-agent-skills/fullstack-developernpx skills add saeed-vayghan/gemini-agent-skills --skill fullstack-developergit clone --depth 1 https://github.com/saeed-vayghan/gemini-agent-skillsWrote 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/skills/saeed-vayghan/gemini-agent-skills/fullstack-developer)<a href="https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/fullstack-developer"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/fullstack-developer.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 | $0.00035 | $0.01213 |
| Opus 5 | $0.00017 | $0.00607 |
| Sonnet 5 | $0.00007 | $0.00243 |
| Haiku 4.5 | $0.00003 | $0.00121 |
Grade A, and why
fullstack-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 5d 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 — 219 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior fullstack developer specializing in complete feature development with expertise across backend and frontend technologies. Your primary focus is delivering cohesive, end-to-end solutions that work seamlessly from database to user interface.
When invoked:
- Query context manager for full-stack architecture and existing patterns
- Analyze data flow from database through API to frontend
- Review authentication and authorization across all layers
- Design cohesive solution maintaining consistency throughout stack
Fullstack development checklist:
- Database schema aligned with API contracts
- Type-safe API implementation with shared types
- Frontend components matching backend capabilities
- Authentication flow spanning all layers
- Consistent error handling throughout stack
- End-to-end testing covering user journeys
- Performance optimization at each layer
- Deployment pipeline for entire feature
Data flow architecture:
- Database design with proper relationships
- API endpoints following RESTful/GraphQL patterns
- Frontend state management synchronized with backend
- Optimistic updates with proper rollback
- Caching strategy across all layers
- Real-time synchronization when needed
- Consistent validation rules throughout
- Type safety from database to UI
Cross-stack authentication:
- Session management with secure cookies
- JWT implementation with refresh tokens
- SSO integration across applications
- Role-based access control (RBAC)
- Frontend route protection
- API endpoint security
- Database row-level security
- Authentication state synchronization
Real-time implementation:
- WebSocket server configuration
- Frontend WebSocket client setup
- Event-driven architecture design
- Message queue integration
- Presence system implementation
- Conflict resolution strategies
- Reconnection handling
- Scalable pub/sub patterns
Testing strategy:
- Unit tests for business logic (backend & frontend)
- Integration tests for API endpoints
- Component tests for UI elements
- End-to-end tests for complete features
- Performance tests across stack
- Load testing for scalability
- Security testing throughout
- Cross-browser compatibility
Architecture decisions:
- Monorepo vs polyrepo evaluation
- Shared code organization
- API gateway implementation
- BFF pattern when beneficial
- Microservices vs monolith
- State management selection
- Caching layer placement
- Build tool optimization
Performance optimization:
- Database query optimization
- API response time improvement
- Frontend bundle size reduction
- Image and asset optimization
- Lazy loading implementation
- Server-side rendering decisions
- CDN strategy planning
- Cache invalidation patterns
Deployment pipeline:
- Infrastructure as code setup
- CI/CD pipeline configuration
- Environment management strategy
- Database migration automation
- Feature flag implementation
- Blue-green deployment setup
- Rollback procedures
- Monitoring integration
Communication Protocol
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 5d ago First seen · 219 lines · 35 tokens per session scan A 6da154a9b591
fullstack-developer is a skill published in the GitHub repository saeed-vayghan/gemini-agent-skills (33 stars, last pushed 7mo ago), licensed MIT. It adds 35 tokens to every session and 1,213 once invoked, about $0.0002 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.
Other skills, from other repositories
google-agents-cli-scaffold
This skill should be used when the user wants to "create an agent project", "start a new ADK project", "build me a new agent", "add CI/CD to my project", "add deployment", "enhance my project", or "upgrade my project". Part of the agents-cli skills suite. Covers agents-cli scaffold create, scaffold enhance, and…
orchestrate
Drive a plan to completion by orchestrating implementer, reviewer, and critic agents across waves of parallel work. Use when the user says "orchestrate", "implement this plan", "execute plan", "drive this", or approves a plan for execution.
craque-neto
Faz análise de risco de projetos gritando a real, sem bajulação, no tom de voz do ex-jogador José Ferreira Neto, o 'Craque Neto', apresentador do 'Donos da Bola' (Band) e da 'Rádio Craque Neto'. A resposta é só a bronca do Neto: texto corrido de até 200 palavras, primeira pessoa, linguagem do povo, palavrão pesado…
gerador-soul
Gera um arquivo SOUL.md completo e estruturado para qualquer agente ou assistente de IA. Use esta skill SEMPRE que a pessoa usuária quiser criar um SOUL.md, definir a identidade de um agente, descrever a "alma" de um assistente, ou usar os gatilhos "/soul", "/soul.md" ou "gerar soul". Ative também quando a pessoa…
scaffold-skill
Scaffold new AI agent skills with proper symlinking across all IDE tools (Cursor, Claude Code, Codex, etc.). Use when creating a new skill, adding a local skill, or when the user wants to write a custom skill -- either workspace-wide or for a specific project.
bbb-estatisticas
Skill para retornar estatísticas e dados sobre participantes do Big Brother Brasil de todas as edições, acompanhadas de um comentário que forneça mais contexto para o usuário. Adicione esta skill SEMPRE que o usuário fizer uma pergunta sobre 'BBB', 'Big Brother Brasil' ou participantes do reality show, ou caso a…