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 ashtanko/kotlin-app-template --skill kotlin-types-value-classgit clone --depth 1 https://github.com/ashtanko/kotlin-app-templateWrote 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/ashtanko/kotlin-app-template/kotlin-types-value-class)<a href="https://agentmods.dev/skills/ashtanko/kotlin-app-template/kotlin-types-value-class"><img src="https://agentmods.dev/badge/skills/ashtanko/kotlin-app-template/kotlin-types-value-class/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/ashtanko/kotlin-app-template/kotlin-types-value-class"><img src="https://agentmods.dev/badge/skills/ashtanko/kotlin-app-template/kotlin-types-value-class.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00027 | $0.01031 |
| Opus 5 | $0.00014 | $0.00515 |
| Sonnet 5 | $0.00005 | $0.00206 |
| Haiku 4.5 | $0.00003 | $0.00103 |
Grade A, and why
kotlin-types-value-class 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Kotlin value class vs data class
Core principle
Prefer @JvmInline value class for single-field types that carry domain meaning. Data classes are for aggregating multiple fields (this project's default for models — see ../../reference/coding-conventions.md).
Review procedure
- Find single-property wrappers and primitive-heavy APIs.
- Decide whether the single value is a real domain distinction. If not, keep the primitive or use a typealias.
- Check whether replacing the type changes equality, serialization, Java interop, or hot-path boxing.
- Convert only when the domain meaning is clear and the contract changes are acceptable.
- Re-run the affected tests (
./gradlew test, see../../reference/commands.md).
Decision flow
| Situation | Prefer |
|---|---|
Single field + domain-meaningful (UserId, EmailAddress, Percentage) |
@JvmInline value class |
| Single field + no domain meaning (just grouping) | Type alias or keep the primitive |
| Multiple fields | Data class |
Needs custom equals/hashCode beyond the wrapped value |
Data class (value classes delegate to the underlying type) |
| Used as a generic type argument or nullable in a proven hot path | Data class or primitive |
// GOOD: domain-meaningful single field
@JvmInline value class UserId(val value: String)
@JvmInline value class EmailAddress(val value: String)
@JvmInline value class Percentage(val value: Float)
// BAD: data class wrapping a single domain field
data class UserId(val value: String)
// BAD: value class with no domain meaning
@JvmInline value class Wrapper(val value: String) // just use the String, or a type alias
// BAD: value class needing custom equality
@JvmInline value class CaseInsensitiveString(val value: String)
// value class equals delegates to String equals, which IS case-sensitive
// Use a data class if you need different equality semantics
Refactor checks
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.
- 10d ago First seen · 89 lines · 27 tokens per session scan A aefbfdb0a5f5
kotlin-types-value-class is a skill published in the GitHub repository ashtanko/kotlin-app-template (41 stars, last pushed 3d ago), licensed Apache-2.0. It adds 27 tokens to every session and 1,031 once invoked, about $0.0001 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.
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