android-reverse-engineering

A toolkit for examining Android apps and Java libraries by decompiling their packaged code. It supports APK, XAPK, JAR, and AAR files and can trace how screens call network APIs.

In plain words
What is it for?
Use it to fingerprint an app, extract HTTP endpoints from libraries such as Retrofit or OkHttp, follow calls from the user interface to the network layer, and document the results.
Why use it?
It helps turn compiled packages into code and documentation that a developer can inspect. Using jadx and optionally other decompilers allows comparison when the output is difficult to read.

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/simoneavogadro/android-reverse-engineering-skill/android-reverse-engineering
Any agent
npx skills add SimoneAvogadro/android-reverse-engineering-skill --skill android-reverse-engineering
Clone the repo
git clone --depth 1 https://github.com/SimoneAvogadro/android-reverse-engineering-skill

Made for: Claude Code, Codex.

Per session 117 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,878 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00117 $0.03878
Opus 5 $0.00059 $0.01939
Sonnet 5 $0.00023 $0.00776
Haiku 4.5 $0.00012 $0.00388

Measured 2d ago against content hash d06dbd15c4be, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

android-reverse-engineering scanned grade B with 1 finding 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 2d ago.

The scan reads SKILL.md. This mod also ships 11 executable files (scripts/check-deps.ps1, scripts/check-deps.sh, scripts/decompile.ps1, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- Installs without sudo when possible (downloads to `~/.local/share/`, symlinks in `~/.local/bin/`)
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

plugins/android-reverse-engineering/skills/android-reverse-engineering/SKILL.md · 313 lines

How it starts

The opening of the file, as written. The whole thing — 313 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Android Reverse Engineering

Decompile Android APK, XAPK, JAR, and AAR files using jadx and Fernflower/Vineflower, trace call flows through application code and libraries, and produce structured documentation of extracted APIs. Two decompiler engines are supported — jadx for broad Android coverage and Fernflower for higher-quality output on complex Java code — and can be used together for comparison.

Prerequisites

This skill requires Java JDK 17+ and jadx to be installed. Fernflower/Vineflower and dex2jar are optional but recommended for better decompilation quality. Run the dependency checker to verify:

bash ${CLAUDE_PLUGIN_ROOT}/skills/android-reverse-engineering/scripts/check-deps.sh

On Windows (PowerShell):

& "${CLAUDE_PLUGIN_ROOT}/skills/android-reverse-engineering/scripts/check-deps.ps1"

If anything is missing, follow the installation instructions in ${CLAUDE_PLUGIN_ROOT}/skills/android-reverse-engineering/references/setup-guide.md.

Workflow

Phase 0: Fingerprint the App (recommended before anything else)

Before installing tools or decompiling, run a fast triage to determine what kind of app you are looking at. Decompiling Java is mostly useless for Flutter, React Native, Cordova/Capacitor, and Xamarin apps — the real code lives elsewhere. The fingerprint script tells you which.

bash ${CLAUDE_PLUGIN_ROOT}/skills/android-reverse-engineering/scripts/fingerprint.sh <file.apk|file.xapk>

It prints, in one screen:

  • Mobile framework (Flutter / React Native / Cordova / Xamarin / Native Kotlin / etc.) with the file marker that triggered the verdict.
  • HTTP stack (Retrofit, OkHttp, Ktor, Apollo, Volley) detected via DEX string scan — works even when class names are obfuscated.
  • DI / serialization signals (Hilt, Dagger, Koin, kotlinx.serialization, Moshi, Gson, Jackson).
  • Obfuscation level estimate based on root-level short-named packages.
  • Notable third-party SDKs (AppsFlyer, Datadog, Sentry, Firebase, payment SDKs, support/chat SDKs, etc.).
  • Consolidated native libraries across the base APK and all splits — XAPK split bundles often place .so files in config.<abi>.apk, not in base.apk.
  • Recommended next step, which differs by framework (e.g. for Flutter the script suggests blutter / strings libapp.so rather than jadx).

Read the full file on GitHub · 313 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. 2d ago First seen · 313 lines · 117 tokens per session scan B d06dbd15c4be

Subscribe to this mod's changes

android-reverse-engineering is a skill published in the GitHub repository SimoneAvogadro/android-reverse-engineering-skill (7,677 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 117 tokens to every session and 3,878 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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