kotlin-dev

kotlin-dev is a skill for Claude Code from pranav8494/team-of-agents. It costs 32 tokens per session (3,215 once invoked), scanned A, original, MIT.

A development guide for building and fixing Kotlin applications that use Spring Boot, a framework for JVM web services. It covers code structure, testing, configuration, security, and database changes.

In plain words
What is it for?
Implementing Kotlin/Spring Boot features and endpoints, fixing bugs with failing tests first, designing data models and APIs, and handling validation, security, observability, and database migrations.
Why use it?
It helps keep new behaviour covered by tests and places code in the appropriate application layer. It also surfaces configuration, security, and migration work that could otherwise be missed.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the team-of-agents plugin — 18 skills, 17 agents, 1 hook shipped together

Good fit Implementing Kotlin/Spring Boot features and endpoints, fixing bugs with failing tests first, designing data models and APIs, and handling validation, security, observability, and database migrations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pranav8494/team-of-agents/kotlin-backend-engineer
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 pranav8494/team-of-agents --skill kotlin-backend-engineer
Clone the repo
git clone --depth 1 https://github.com/pranav8494/team-of-agents

Made for: Claude Code.

Or install team-of-agents, the plugin that ships this one along with the rest of its 18 skills, 17 agents, 1 hook.

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 kotlin-dev

README.md
[![agentmods](https://agentmods.dev/badge/skills/pranav8494/team-of-agents/kotlin-backend-engineer/github.svg)](https://agentmods.dev/skills/pranav8494/team-of-agents/kotlin-backend-engineer)
Your own site
<a href="https://agentmods.dev/skills/pranav8494/team-of-agents/kotlin-backend-engineer"><img src="https://agentmods.dev/badge/skills/pranav8494/team-of-agents/kotlin-backend-engineer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for kotlin-dev

Your own site · 80×15
<a href="https://agentmods.dev/skills/pranav8494/team-of-agents/kotlin-backend-engineer"><img src="https://agentmods.dev/badge/skills/pranav8494/team-of-agents/kotlin-backend-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,215 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00032 $0.03215
Opus 5 $0.00016 $0.01607
Sonnet 5 $0.00006 $0.00643
Haiku 4.5 $0.00003 $0.00321

Measured 12d ago against content hash 0601b5c62548, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

kotlin-dev scanned grade A with 1 finding 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 12d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

items.map { async { fetch(it) } }.awaitAll()
skills/kotlin-backend-engineer/SKILL.md · 286 lines

How it starts

The opening of the file, as written. The whole thing — 286 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Kotlin Developer Skill

Iron Law

No new behaviour without a test that fails first, then passes.

Before Taking Any Action

  1. Announce what you intend to do and why
  2. Explain the approach, data model decisions, Spring configuration, security implications, migration steps, trade-offs
  3. Ask for confirmation before writing or editing any file, running any command, or executing any database operation
  4. Report what was created or changed, and flag follow-up items (new env vars, Flyway migrations to run, Spring Security config to update)

Task Approach

Use this table to determine what to produce for each task type:

User asks for What to produce
New feature / endpoint Clarify idempotency, consistency, and compliance requirements; propose data model and API contract first; search codebase for reuse candidates; implement thin controller → service → adapter/repository with validation at the controller boundary and domain exceptions mapped at the adapter boundary
Bug fix Reproduce with a failing test first; identify whether the fault is in controller, service, adapter, or data layer; fix at the root cause and confirm the test passes
Data model / schema Normalised table definitions, surrogate key choice, index plan for every query path, Flyway migration (forward-only, backward-compatible, zero-downtime), EXPLAIN ANALYZE for non-trivial queries
Code review Per-layer feedback: constructor injection, resilience wrapping on external calls, @Transactional scope, BigDecimal for currency, idempotency of financial operations, PII/card data absent from logs, Flyway migration safety, index coverage, metrics on new external calls
API design RESTful resource structure, HTTP status code table, Problem Details error shape (RFC 9457), OpenAPI (Springdoc) spec, Bean Validation placement
Testing Unit test with @WebMvcTest + MockK/Mockito-Kotlin for controllers and services; Testcontainers integration test for repositories; WireMock for outbound HTTP; property-based tests for financial edge cases
Observability / metrics Micrometer counter/timer with {org}.{domain}.{action} naming, result tag (success/failure), OkHttp metrics listener registration, KotlinLogging lambda form with correlation and entity IDs
Performance optimisation Identify bottleneck with EXPLAIN ANALYZE or profiling; tune HikariCP pool size; introduce coroutine parallelism (async/awaitAll) for independent I/O; cache stable reads with @Cacheable
Security configuration Spring Security JWT/OAuth2 resource server config in dedicated SecurityConfig, @PreAuthorize placement, secret storage guidance, fintech compliance checklist

Read the full file on GitHub · 286 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. 12d ago First seen · 286 lines · 32 tokens per session scan A 0601b5c62548

Subscribe to this mod's changes

kotlin-dev is a skill published in the GitHub repository pranav8494/team-of-agents (7 stars, last pushed 1mo ago), licensed MIT. It adds 32 tokens to every session and 3,215 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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