Kotlin Patterns

Kotlin Patterns is a skill for Claude Code, Codex from AmariahAK/atlarix-skills. It costs 3 tokens per session (343 once invoked), scanned A, original, Apache-2.0.

A set of coding guidelines for Kotlin applications running on the Java Virtual Machine (JVM). It covers handling missing values, running asynchronous work, organizing Gradle modules, and testing.

In plain words
What is it for?
Use it when writing or reviewing Kotlin JVM projects, including Gradle builds, coroutine-based code, and tests.
Why use it?
It helps prevent runtime crashes from unsafe null handling, stuck or cancelled asynchronous work, and modules with unclear dependencies.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when writing or reviewing Kotlin JVM projects, including Gradle builds, coroutine-based code, and tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/amariahak/atlarix-skills/kotlin
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 AmariahAK/atlarix-skills --skill kotlin
Clone the repo
git clone --depth 1 https://github.com/AmariahAK/atlarix-skills

Made for: Claude Code, Codex.

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 Patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/amariahak/atlarix-skills/kotlin/github.svg)](https://agentmods.dev/skills/amariahak/atlarix-skills/kotlin)
Your own site
<a href="https://agentmods.dev/skills/amariahak/atlarix-skills/kotlin"><img src="https://agentmods.dev/badge/skills/amariahak/atlarix-skills/kotlin/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 Patterns

Your own site · 80×15
<a href="https://agentmods.dev/skills/amariahak/atlarix-skills/kotlin"><img src="https://agentmods.dev/badge/skills/amariahak/atlarix-skills/kotlin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 3 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 343 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.
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 $0.00003 $0.00343
Opus 5 $0.00002 $0.00171
Sonnet 5 $0.00001 $0.00069
Haiku 4.5 $0.00000 $0.00034

Measured 9d ago against content hash 9530121ed20d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

Kotlin Patterns 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 9d 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/kotlin/SKILL.md · 53 lines

What it actually says

Kotlin Patterns

When to use this skill

Use this skill when working on Kotlin JVM projects and you want consistent patterns for null-safety, coroutines, and clean module boundaries.

Core patterns

Null-safety as a design tool

Prefer:

  • non-null types by default
  • validating external inputs early
  • avoiding !! (it’s a runtime crash)

Coroutines (when used)

Rules:

  • structured concurrency
  • cancellation-aware design
  • avoid blocking calls in coroutine contexts

Gradle structure

  • keep build scripts readable
  • avoid copy-pasting plugin config across modules; share via convention plugins if needed

Testing

  • unit tests for pure logic
  • integration tests for wiring and persistence

Atlarix tool notes

  • Explore: detect Gradle Kotlin DSL (build.gradle.kts) and locate entry points.
  • Build: run ./gradlew test / ./gradlew build.
  • Debug: follow stack traces; confirm coroutine context + dispatcher usage.
  • Review: check null-safety and coroutine cancellation.

Common mistakes to avoid

  • Using !! to “fix” nullability
  • Blocking in coroutines
  • God modules with unclear dependencies

Mini-checklist

  • Nullability is intentional
  • Coroutines are structured
  • Tests cover critical paths
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. 9d ago First seen · 53 lines · 3 tokens per session scan A 9530121ed20d

Subscribe to this mod's changes

Kotlin Patterns is a skill published in the GitHub repository AmariahAK/atlarix-skills (2 stars, last pushed 6d ago), licensed Apache-2.0. It adds 3 tokens to every session and 343 once invoked, about $0.0000 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.

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