Amethyst is an Android client for Nostr, a social network protocol that lets people control their own social activity and connections. People use it to read and publish Nostr content, follow accounts, and exchange encrypted direct messages from Android and other supported platforms. The catalogue add-ons support workflows for developing or operating the client.
Borrowing it
Nothing to install: this file belongs to vitorpamplona/amethyst. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/vitorpamplona/amethyst/main/.claude/skills/kotlin-multiplatform/SKILL.mdgit clone --depth 1 https://github.com/vitorpamplona/amethystWrote 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/vitorpamplona/amethyst/kotlin-multiplatform)<a href="https://agentmods.dev/skills/vitorpamplona/amethyst/kotlin-multiplatform"><img src="https://agentmods.dev/badge/skills/vitorpamplona/amethyst/kotlin-multiplatform/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/vitorpamplona/amethyst/kotlin-multiplatform"><img src="https://agentmods.dev/badge/skills/vitorpamplona/amethyst/kotlin-multiplatform.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- 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 | $0.00000 | $0.01669 |
| Opus 5.5 | $0.00000 | $0.00668 |
| Sonnet 5.5 | $0.00000 | $0.00334 |
| Haiku 4.5 | $0.00000 | $0.00167 |
Grade A, and why
kotlin-multiplatform 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.
How it starts
The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Kotlin Multiplatform and Gradle in Amethyst
Module roles, the "share vs keep native" rule and the CLI-safe boundary are in
AGENTS.md (Architecture, Feature Workflow). Package placement inside commons /
commonsUI is in commons/ARCHITECTURE.md ("Where does my code go?", "Source sets")
and commonsUI/ARCHITECTURE.md ("Platform slots"). Read those first; this skill
adds the source-set mechanics and the build traps.
Modules
settings.gradle.kts includes 13: amethyst, nappletHost, benchmark,
baselineprofile, geode, commons, commonsUI, nestsClient,
marmotQuic, desktopApp, cli, relayBench, marmotBench. Quartz is the
external libs.quartz (vitorpamplona/quartz) and QUIC the external libs.quic
(vitorpamplona/quic-kmp); -PquartzDir=../quartz / -PquicKmpDir=../quic-kmp build a
local checkout instead (an included build, so quic's own quartz dependency follows).
Source sets
| Source set | Holds | Targets |
|---|---|---|
commonMain |
Pure Kotlin. Compiled for iOS/native too, so no JVM APIs | all |
jvmAndroid |
JVM libraries shared by Android + Desktop: OkHttp, nestsClient, NWC/LNURL |
android, jvm |
androidMain / jvmMain |
Platform actuals (Keystore/DataStore vs keyring, Coil bridges) | one each |
iosMain, appleMain, nativeMain, linuxMain, macosMain |
quartz only (plus iosMain in commons/commonsUI) |
Apple / native |
skikoMain |
commonsUI code shared by Desktop and iOS | jvm, ios |
Targets: quartz builds android, jvm, iosArm64, iosSimulatorArm64, linuxX64,
macosArm64. commons and commonsUI build android, jvm, iosArm64,
iosSimulatorArm64. nestsClient, marmotQuic are android + jvm. There is
no iosX64.
jvmAndroid is a custom intermediate set created with create("jvmAndroid")
before androidMain/jvmMain depend on it (see commons/build.gradle.kts).
Prefer the most common set that compiles: commonMain → jvmAndroid → platform.
kotlinx.serialization is the house JSON stack and OkHttp the house HTTP stack
(AGENTS.md › Tech Stack). Nostr JSON (events, messages, filters, tags) goes through
quartz's Kite (OptimizedJsonMapper, KiteWriter, KitePretty); quartz dropped Jackson
in 2.4.0, so don't add Jackson back. Don't migrate JVM HTTP to Ktor. Jackson and OkHttp
are banned in iOS-compiled sets, which the purity gate enforces.
What ships with it
1 file 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.
- 9d ago Changed 5655fadbc69b
- 14d ago Changed · +2 lines 3d33ae652c50
- 15d ago Changed 5a0a02addf8d
- 16d ago Changed · +2 lines 0fb96cfe3cd2
- 25d ago Changed · -309 lines · -119 tokens per session f1e129475357
- 1mo ago Changed · +5 lines 2251017af04f
- 1mo ago Changed 7024d6aba290
- 2mo ago First seen · 403 lines · 119 tokens per session scan A 355a91b8d9f5
kotlin-multiplatform is a skill published in the GitHub repository vitorpamplona/amethyst (1,620 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,669 tokens. 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.
kotlin-multiplatform compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| kotlin-multiplatformvitorpamplona/amethyst | Skill | 1.6k | yesterday | MIT | A | 0 | Claude Code |
| compose-animationschrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 64 | Claude Code |
| compose-focus-navigationchrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 41 | Claude Code |
| kotlin-androidericrisco/rsc-harness | Skill | 503 | 2d ago | MIT | A | 78 | Claude Code, Codex |
| compose-multiplatformericrisco/rsc-harness | Skill | 503 | 2d ago | MIT | A | 80 | Claude Code, Codex |
| release-kotlin-librarychrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 46 | Claude Code |
| using-chrisbanes-skillschrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 38 | Claude Code |