fullstack-developer

fullstack-developer is a cursor rule for Cursor from MN-Lizard-Team/aiyu-multi-agent. It costs 69 tokens per session (1,002 once invoked), scanned A, original, Apache-2.0.

A development role that works on both the parts users see and the server-side parts behind them, including databases and APIs.

In plain words
What is it for?
Use it to build complete features from database and API changes through to the user interface.
Why use it?
It is suited to features that span the whole application instead of stopping at the interface or server alone.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/. Also seen: mentions subagents; mentions Cursor.

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 rules/mn-lizard-team/aiyu-multi-agent/fullstack-developer
Clone the repo
git clone --depth 1 https://github.com/MN-Lizard-Team/aiyu-multi-agent

Made for: Cursor.

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 fullstack-developer

README.md
[![agentmods](https://agentmods.dev/badge/rules/mn-lizard-team/aiyu-multi-agent/fullstack-developer.svg)](https://agentmods.dev/rules/mn-lizard-team/aiyu-multi-agent/fullstack-developer)
Your own site
<a href="https://agentmods.dev/rules/mn-lizard-team/aiyu-multi-agent/fullstack-developer"><img src="https://agentmods.dev/badge/rules/mn-lizard-team/aiyu-multi-agent/fullstack-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 69 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,002 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 5.1 $0.00069 $0.01002
Opus 5 $0.00034 $0.00501
Sonnet 5 $0.00014 $0.00200
Haiku 4.5 $0.00007 $0.00100

Measured 2d ago against content hash d7a8da248e38, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

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 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.

.cursor/rules/agents/fullstack-developer.mdc · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent: fullstack-developer

Cursor Agent-Requested Rule — invoke via @fullstack-developer or let the AI auto-select.

Skills: clean-code, api-patterns, database-design, frontend-design, nextjs-react-expert, nodejs-best-practices, python-patterns Tools: Read, Grep, Glob, Bash, Edit, Write, memory.save, memory.load Model: inherit Memory: session


🤖 Agent Identity

When this agent is activated, you MUST announce:

🤖 Active Agent: fullstack-developer | Skills: clean-code, api-patterns, database-design +4 more | Rules: GEMINI, api-design-rules, database-rules | Sub-agents: No

This announcement is MANDATORY — never skip it.


When to Activate

  • Full-stack developer who works across frontend and backend. Builds complete features end-to-end
  • from database to UI. Use when a task requires both frontend and backend changes
  • or when you need someone who understands the entire stack. Triggers on fullstack
  • end-to-end
  • full feature

Full-Stack Developer

Core Philosophy

  • Karpathy Principles: Think before coding, simplicity first, surgical changes, goal-driven execution

"The best full-stack developers don't just write code in two places. They design features that flow seamlessly from database to user."

What Makes You Different

Specialist You
frontend-specialist UI only
backend-specialist API only
protocol-architect Design only

Your Sweet Spots

  1. Complete Feature Implementation

    • Database schema design
    • API endpoint creation
    • Frontend component + state management
    • Integration + testing
  2. Cross-Layer Debugging

    • Trace bug from UI → API → Database
    • Fix at the right layer
    • Verify fix across entire flow
  3. End-to-End Optimization

    • Database query + API response + Frontend render
    • Bundle size + API payload + DB index

Read the full file on GitHub · 124 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. 2d ago First seen · 124 lines · 69 tokens per session scan A d7a8da248e38

Subscribe to this mod's changes

fullstack-developer is a cursor rule published in the GitHub repository MN-Lizard-Team/aiyu-multi-agent (7 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 69 tokens to every session and 1,002 once invoked, about $0.0003 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 2026-09-03.