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.
npx skills add williamzujkowski/standards --skill kotlingit clone --depth 1 https://github.com/williamzujkowski/standardsWrote 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.
[](https://agentmods.dev/skills/williamzujkowski/standards/kotlin)<a href="https://agentmods.dev/skills/williamzujkowski/standards/kotlin"><img src="https://agentmods.dev/badge/skills/williamzujkowski/standards/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.
<a href="https://agentmods.dev/skills/williamzujkowski/standards/kotlin"><img src="https://agentmods.dev/badge/skills/williamzujkowski/standards/kotlin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00037 | $0.01790 |
| Opus 5.5 | $0.00015 | $0.00716 |
| Sonnet 5.5 | $0.00007 | $0.00358 |
| Haiku 4.5 | $0.00004 | $0.00179 |
Grade A, and why
kotlin-coding-standards 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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Kotlin Coding Standards
Level 1: Quick Reference
Null Safety Cheat Sheet
// Safe Call (?.) - Returns null if receiver is null
val length = user?.name?.length
// Elvis Operator (?:) - Provides default value
val name = user?.name ?: "Unknown"
// Not-Null Assertion (!!) - Throws NPE if null (avoid!)
val length = user!!.name!!.length
// Safe Cast (as?) - Returns null on cast failure
val employee = person as? Employee
Scope Functions
| Function | Context | Returns | Use Case |
|---|---|---|---|
let |
it |
Lambda result | Null checks, transforms |
apply |
this |
Receiver | Object configuration |
also |
it |
Receiver | Side effects, logging |
run |
this |
Lambda result | Object config + compute |
with |
this |
Lambda result | Grouping calls |
// let - transform or null check
user?.let { println("Name: ${it.name}") }
// apply - configure object
val user = User().apply {
name = "Alice"
email = "[email protected]"
}
Core Patterns
// Data Classes - auto equals, hashCode, toString, copy
data class User(val id: String, val name: String, val email: String)
// Sealed Classes - restricted hierarchies
sealed class Result<out T> {
data class Success<T>(val data: T) : Result<T>()
data class Error(val message: String) : Result<Nothing>()
object Loading : Result<Nothing>()
}
// Extension Functions - add to existing classes
fun String.isValidEmail(): Boolean =
android.util.Patterns.EMAIL_ADDRESS.matcher(this).matches()
Essential Checklist
- Use nullable types (?) instead of !! operator
- Prefer immutable (val) over mutable (var)
- Use data classes for DTOs
- Sealed classes for state management
- Configure detekt + ktlint
- Avoid platform types from Java interop
Level 2: Implementation Guide
1. Null Safety Patterns
Smart Casts - Compiler tracks null checks:
fun processUser(user: User?) {
if (user != null) {
// Smart cast to User
println(user.name)
}
}
// Early return pattern
fun getUserName(user: User?): String {
user ?: return "Unknown"
return user.name // Smart cast after check
}
What ships with it
7 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.
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.
- yesterday First seen · 287 lines · 37 tokens per session scan A b7cd95928eba
kotlin-coding-standards is a skill published in the GitHub repository williamzujkowski/standards (18 stars, last pushed 1mo ago), licensed MIT. It adds 37 tokens to every session and 1,790 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-29.
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