android-dev

A baseline guide for Android and Kotlin Multiplatform development. Kotlin Multiplatform lets shared code run across platforms such as Android and iOS.

In plain words
What is it for?
It guides work involving Android, Kotlin, KMP, Jetpack Compose, Gradle, Hilt, Koin, Room, Retrofit, Ktor, ViewModel, and state or flow APIs.
Why use it?
It gives projects consistent defaults for dependency injection, asynchronous work, data storage, networking, errors, and module boundaries. It also routes different Android tasks to more specific guidance.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/rcosteira79/android-skills/android-dev
Any agent
npx skills add rcosteira79/android-skills --skill android-dev
Clone the repo
git clone --depth 1 https://github.com/rcosteira79/android-skills

Made for: Claude Code, Codex.

Per session 217 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,847 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00217 $0.02847
Opus 5 $0.00109 $0.01424
Sonnet 5 $0.00043 $0.00569
Haiku 4.5 $0.00022 $0.00285

Measured 3d ago against content hash 869a9fe82927, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

android-dev 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 3d 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.

plugins/android-skills/skills/android-dev/SKILL.md · 166 lines

How it starts

The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Android / KMP baseline

House defaults — apply them without reminders or re-derivation; where the project's actual conventions differ, follow the project:

  • DI: Hilt + KSP (or android-skills:koin when the project uses Koin). Async: Coroutines/Flow — no LiveData in new code. JSON: kotlinx.serialization. Images: Coil.
  • Network/local: Android uses Retrofit/OkHttp + Room; KMP shared uses Ktor + Room or SQLDelight. Retrofit is Android-only — never in a shared module.
  • Modules: feature-vertical packages and modules; :core:model has zero Android deps; :feature:* modules never depend on each other.
  • Errors: mapped to a domain type at the repository boundary — platform exceptions never leak past it; UI state explicitly models loading / success / error (see android-skills:android-data-layer).

Skill routing

Load the specific skill for the task, always with the fully-qualified android-skills: prefix — never the short name (compose, koin, …).

For Load
Compose detail — stability, remember, modifiers, side effects, lists, animation, navigation android-skills:compose
M3 UX — touch targets, adaptive/foldable layouts, accessibility & M3-compliance audit android-skills:android-ux
Coroutines & Flow — operators, Channel vs SharedFlow, structured concurrency android-skills:kotlin-coroutines, android-skills:kotlin-flows
Repository / data layer + error model android-skills:android-data-layer
Networking android-skills:android-retrofit (Android) · android-skills:kmp-ktor (KMP)
Paging android-skills:paging
Image loading android-skills:coil-compose
Preferences / typed local storage android-skills:datastore
KMP expect/actual boundary design android-skills:kmp-boundaries
RxJava → Coroutines/Flow migration android-skills:rxjava-migration
Testing android-skills:android-testing
DI with Koin android-skills:koin
Build logic / convention plugins android-skills:android-gradle-logic
Build speed, kapt → KSP android-skills:gradle-build-performance
Debugging — Logcat, crashes, ANRs, profiling android-skills:android-debugging
AOSP / AndroidX source lookup android-skills:android-source-search
Multi-module visibility & module boundaries android-skills:modularization
Platform PDF annotation / page-object editing (API 36.1 / SDK ext 18) android-skills:pdf-annotations

Read the full file on GitHub · 166 lines

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. 3d ago First seen · 166 lines · 217 tokens per session scan A 869a9fe82927

Subscribe to this mod's changes

android-dev is a skill published in the GitHub repository rcosteira79/android-skills (136 stars, last pushed 8d ago), licensed MIT. It adds 217 tokens to every session and 2,847 once invoked, about $0.0011 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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