AI Skill StudioAI Skill Studio
Skills
Presets:

Target Standard & File Format

AI Agent Rules & Skills
Context Shields & Privacy (Ignore Files)
Integrations & Machine Documentation
AI Governance & Multi-Agent Planning Suite

Identity & Activation Rules

3 chips
Scoped domain keywords evaluated in real time
api-routescode-auditsrefactoring
Suggested Chips:

Technology Stack Context

Engineering Philosophy

Flexible & Adaptable

Architectural & Code Quality Conventions

Less rigid & configurable

Agent Behavioral Guardrails

Select active rules
Security & Trust Boundaries
Always included
  • Untrusted Content Is Data
  • Encoded Payloads
  • Least-Privilege File Access
  • Confirm Irreversible Actions
  • Secret Handling
  • Validation Failures
  • Conflicting Requests

Step-by-Step Workflow Procedures

Spring Boot 3 & Java 21 OpenAI Custom Instructions

Generate OpenAI ChatGPT and Playground custom instructions for Spring Boot 3 & Java 21. Custom system instructions for OpenAI ChatGPT and the API playground anchor model behavior to strict Spring Boot 3 & Java 21 standards, enforcing concise diffs, schema validation, and defensive error handling.

Target Path
prompts/openai-custom-instructions.md
Execution Scope
Pasted or sent per request
Specification Format
Markdown (.md)
AI Tool Support
ChatGPT and the OpenAI API
02 / WHY IT HELPS

What this file changes for Spring Boot 3 & Java 21

Without it

Custom system instructions for OpenAI ChatGPT and the API playground anchor model behavior to strict Spring Boot 3 & Java 21 standards, enforcing concise diffs, schema validation, and defensive error handling.

What the file tells the agent
Use jakarta.* packages for persistence, validation, and servlets; ban legacy javax.* imports.
Represent immutable request/response DTOs using native Java Records with Jakarta validation annotations.
Enable Java 21 Virtual Threads (spring.threads.virtual.enabled=true) for high-throughput non-blocking I/O.
Configure Spring Security using the modern SecurityFilterChain bean approach; never extend deprecated WebSecurityConfigurerAdapter.
Avoid N+1 queries in Spring Data JPA: use @EntityGraph or JOIN FETCH JPQL queries for relational fetches.
03 / CODE PATTERNS

Spring Boot 3 & Java 21: code to avoid and code to write instead

Avoid
// Discouraged: Legacy javax namespace, verbose POJO with setters, mutable entity exposure
import javax.persistence.*; // Obsolete in Spring Boot 3!

public class BadOrderDTO {
    private String customerId;
    public void setCustomerId(String id) { this.customerId = id; }
}
Write instead
package com.example.demo.order;

import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.Positive;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.math.BigDecimal;

public record CreateOrderRequest(
    @NotBlank String customerId,
    @Positive BigDecimal amount
) {}

public record OrderResponse(Long id, String customerId, BigDecimal amount) {}

@RestController
@RequestMapping("/api/v1/orders")
public class OrderController {
    private final OrderService orderService;

    public OrderController(OrderService orderService) {
        this.orderService = orderService;
    }

    @PostMapping
    public ResponseEntity<OrderResponse> create(@RequestBody CreateOrderRequest request) {
        OrderResponse response = orderService.processOrder(request);
        return ResponseEntity.ok(response);
    }
}
04 / REPOSITORY PLACEMENT & 3-STEP TERMINAL INSTALLATION

How to Install Spring Boot 3 & Java 21 OpenAI Custom Instructions via Terminal

1

Step 1: Open Project Directory & Verify Target Placement

Open your terminal and navigate to your project root folder where the prompts/openai-custom-instructions.md file will reside. Ensure the file is placed at the exact path below relative to your project root so the AI engine automatically loads it:

prompts/openai-custom-instructions.md
2

Step 2: Fetch Rule File via Terminal Command

Run curl, PowerShell, or wget to stream the rule directly from the DevScratchpad raw API endpoint and write it to prompts/openai-custom-instructions.md:

Terminal One-Liner Install

Run directly in your project root to stream and write this rule file with one command.

Raw API Stream
$mkdir -p "prompts" && curl -fsSL "https://www.devscratchpad.tech/api/raw/openai-instructions/spring-boot-3" -o "prompts/openai-custom-instructions.md"
3

Step 3: Check that ChatGPT and the OpenAI API uses it

Nothing loads this file automatically. Paste it into ChatGPT custom instructions, a Project or a custom GPT, or send it as instructions in the API.

05 / ROUTE DIRECTORY & CROSS-TOOLING
Format Pillar Hub

ChatGPT and OpenAI custom instructions generator for coding

OpenAI Custom Instructions: how it works, where the file goes, and every OpenAI preset.

/openai-instructions Directory
06 / RELATED DEVELOPER TOOLS

Tools for Spring Boot 3 & Java 21 work

Browser-based utilities to test, format and inspect the code your AI tool writes. Nothing you paste is uploaded.

View all 28 tools

Live Repository & Schema Ingestion

Inspect any public or private GitHub repository, or paste SQL DDL and Prisma models directly in AI Skill Studio to auto-generate authentic rules. Zero server transmission.

Launch AI Skill Studio

Migrating from Legacy .cursorrules or CLAUDE.md?

Use the free, in-browser converter to turn one long rules file into Cursor .mdc, Claude SKILL.md or Windsurf rules.

Convert Rules Free
07 / FREQUENTLY ASKED QUESTIONS

Technical FAQ: Spring Boot 3 & Java 21 AI Rulebooks

Where do I apply these OpenAI instructions?

Paste it into ChatGPT custom instructions (Settings > Personalization), a Project's instructions or a custom GPT, or send it as instructions in the OpenAI API.

Which OpenAI models can use these instructions?

Any current model in ChatGPT or the API. The instructions are plain text, so they work the same way whichever model you pick.