openapi-first

openapi-first is a skill for Claude Code, Codex from rrezartprebreza/spring-boot-skills. It costs 55 tokens per session (1,071 once invoked), scanned A, original, MIT.

A development approach where an OpenAPI file defines an API before its implementation is written. OpenAPI is a standard format for describing endpoints, request data, responses, and errors.

In plain words
What is it for?
Use it in Spring Boot projects with files such as openapi.yaml, or tools such as openapi-generator-maven-plugin and ApiDelegate. It covers generated controllers, DTOs, clients, package settings, and contract-driven implementation.
Why use it?
It keeps controllers, data models, and client code aligned with a shared API contract. Generating these pieces from one specification can reduce mismatches between the documented API and the code.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the spring-boot-3-skills plugin — 30 skills shipped together

Good fit Use it in Spring Boot projects with files such as openapi.yaml, or tools such as openapi-generator-maven-plugin and ApiDelegate. It covers generated controllers, DTOs, clients, package settings, and contract-driven implementation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rrezartprebreza/spring-boot-skills/openapi-first
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.

Any agent
npx skills add rrezartprebreza/spring-boot-skills --skill openapi-first
Clone the repo
git clone --depth 1 https://github.com/rrezartprebreza/spring-boot-skills

Made for: Claude Code, Codex.

Or install spring-boot-3-skills, the plugin that ships this one along with the rest of its 30 skills.

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 openapi-first

README.md
[![agentmods](https://agentmods.dev/badge/skills/rrezartprebreza/spring-boot-skills/openapi-first.svg)](https://agentmods.dev/skills/rrezartprebreza/spring-boot-skills/openapi-first)
Your own site
<a href="https://agentmods.dev/skills/rrezartprebreza/spring-boot-skills/openapi-first"><img src="https://agentmods.dev/badge/skills/rrezartprebreza/spring-boot-skills/openapi-first.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,071 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00055 $0.01071
Opus 5 $0.00028 $0.00535
Sonnet 5 $0.00011 $0.00214
Haiku 4.5 $0.00006 $0.00107

Measured 8d ago against content hash 7cc62c921363, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

openapi-first 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 8d 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.

skills/spring-boot-3/openapi-first/SKILL.md · 170 lines

How it starts

The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenAPI-First Development

Maven Plugin Setup

<plugin>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>7.5.0</version>
    <executions>
        <execution>
            <goals><goal>generate</goal></goals>
            <configuration>
                <inputSpec>${project.basedir}/src/main/resources/openapi.yaml</inputSpec>
                <generatorName>spring</generatorName>
                <apiPackage>com.example.api</apiPackage>
                <modelPackage>com.example.api.model</modelPackage>
                <configOptions>
                    <delegatePattern>true</delegatePattern>      <!-- implement delegate, not controller -->
                    <interfaceOnly>false</interfaceOnly>
                    <useSpringBoot3>true</useSpringBoot3>
                    <useTags>true</useTags>
                    <dateLibrary>java8</dateLibrary>
                    <serializationLibrary>jackson</serializationLibrary>
                    <openApiNullable>false</openApiNullable>
                    <skipDefaultInterface>true</skipDefaultInterface>
                </configOptions>
                <generateSupportingFiles>true</generateSupportingFiles>
                <output>${project.build.directory}/generated-sources/openapi</output>
            </configuration>
        </execution>
    </executions>
</plugin>

OpenAPI Spec Example

# src/main/resources/openapi.yaml
openapi: 3.0.3
info:
  title: Order Service API
  version: 1.0.0

paths:
  /api/v1/orders:
    post:
      tags: [Orders]
      operationId: createOrder
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateOrderRequest'
      responses:
        '201':
          description: Order created
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OrderResponse'
        '400':
          $ref: '#/components/responses/ValidationError'

    get:
      tags: [Orders]
      operationId: listOrders
      parameters:
        - name: page
          in: query
          schema: { type: integer, default: 0 }
        - name: size
          in: query
          schema: { type: integer, default: 20 }
      responses:
        '200':
          description: Paginated orders
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OrderPage'

components:
  schemas:
    CreateOrderRequest:
      type: object
      required: [customerEmail, items]
      properties:
        customerEmail:
          type: string
          format: email
        items:
          type: array
          minItems: 1
          items:
            $ref: '#/components/schemas/OrderItemRequest'

    OrderResponse:
      type: object
      properties:
        id:
          type: string
          format: uuid
        status:
          type: string
          enum: [PENDING, PROCESSING, SHIPPED, DELIVERED, CANCELLED]
        customerEmail:
          type: string
        createdAt:
          type: string
          format: date-time

  responses:
    ValidationError:
      description: Validation failed
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'

Read the full file on GitHub · 170 lines

Files

What ships with it

4 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.

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. 8d ago First seen · 170 lines · 55 tokens per session scan A 7cc62c921363

Subscribe to this mod's changes

openapi-first is a skill published in the GitHub repository rrezartprebreza/spring-boot-skills (258 stars, last pushed 24d ago), licensed MIT. It adds 55 tokens to every session and 1,071 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 2026-08-30.