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 ericrisco/rsc-harness --skill kotlin-androidgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/kotlin-android)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/kotlin-android"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/kotlin-android.svg" alt="Measured on agentmods" 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 | $0.00078 | $0.02890 |
| Opus 5 | $0.00039 | $0.01445 |
| Sonnet 5 | $0.00016 | $0.00578 |
| Haiku 4.5 | $0.00008 | $0.00289 |
Grade A, and why
kotlin-android 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 4d 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 — 246 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Native Android with Kotlin & Compose
You build production native Android: Kotlin + Jetpack Compose + the UDF layered architecture (UI → domain → data). One rule governs everything: state flows down, events flow up, and there is exactly one source of truth per piece of state. Get that rule right and recomposition, rotation, and testing fall into place; break it and you get a screen that compiles but recomposes every frame, leaks coroutine scopes, blocks the main thread, or drops state on rotation.
This skill exists to stop the agent from reaching for the 2015 playbook — XML layouts,
findViewById, AsyncTask, LiveData inside Compose, GlobalScope.launch, MutableState
exposed straight out of a ViewModel. Emit a buildable, idiomatic module, not a toy.
Versions floor (2026)
These are floors verified against current docs (2026-06). Re-check the matrix before locking — Compose and AGP move together and a mismatch fails the build.
| Piece | Floor | Why it matters |
|---|---|---|
| Kotlin (KGP) | 2.2.x | K2 compiler is default & Stable; KGP must align with AGP. |
| AGP | 9.2+ when using Compose | Compose's compileSdk 37 requires AGP ≥ 9.2.0. |
| compileSdk | 37 | Current Compose target. |
| minSdk | 24 | Practical modern floor (~99% devices); Compose technically supports 21+. |
| JDK (build) | 17 | Required by current AGP/Compose toolchain. |
| Compose BOM | 2026.05.01 → Compose 1.11.2 | Pin artifacts via the BOM, never per-artifact versions. |
| Navigation | 2.8+ | Type-safe @Serializable routes land here. |
| Hilt + Room + Retrofit | current | DI / persistence / network. Wire Room & Hilt with KSP, not kapt. |
| Serialization | kotlinx.serialization | Retrofit converter + Navigation route types. |
The architecture in one screen
Three layers. Higher layers depend on lower; never the reverse.
UI layer Composable (stateless) ── reads ──> UiState
│ events up ▲ state down
ViewModel exposes StateFlow<UiState> │
│ calls
domain layer (optional) UseCase — only when logic spans repos or is reused
│ calls
data layer Repository (interface in domain, impl here)
├── Room DAO → Flow (single source of truth)
└── Retrofit → suspend (refreshes the source of truth)
What ships with it
5 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.
- 4d ago First seen · 246 lines · 78 tokens per session scan A 51890e0e21a2
kotlin-android is a skill published in the GitHub repository ericrisco/rsc-harness (70 stars, last pushed today), licensed MIT. It adds 78 tokens to every session and 2,890 once invoked, about $0.0004 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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Use when writing or reviewing Kotlin coroutine scope ownership, raw Thread or Executor work, init launches, non-suspending launch APIs, runBlocking, cancellation, StateFlow, SharedFlow, Channel, stateIn, SharingStarted, state updates, or one-shot events.