Stoic

"Σκόπει εἰς σεαυτόν. Ἐντὸς σοῦ πηγὴ ἀγαθοῦ ἐστιν, ἡ ἀεὶ ἐκβρύειν ἑτοίμη, ἐὰν ἀεὶ σκάπτῃς."

"Look within. Within is the fountain of good, and it will ever bubble up, if you will ever dig."

- Marcus Aurelius (121-180 AD), Roman Emperor and Stoic philosopher

"Ignis aurum probat, miseria fortes."

"Fire tests gold and adversity tests the brave."

- Seneca the Younger (c. 4 BC - AD 65), Roman statesman and Stoic philosopher

Run code inside Android processes from your laptop. No APK modifications needed for debuggable apps.

Stoic opens a communication channel into your app. Write plugins that hook methods, inspect heap objects, or call internal APIs—all from the command line.

First attach takes 2-3 seconds. After that, under a second.

Quick Start

brew install block/tap/stoic
stoic helloworld

This runs against a demo app. For your app: stoic --pkg com.yourapp helloworld

Works on API 26+ (Android 8.0+) with debuggable apps. For non-debuggable apps, add the app-sdk.

Bundled Plugins

• appexitinfo - query ApplicationExitInfo API
• breakpoint - hook method calls, print args/returns/stacktraces
• crasher - test crash handling

Writing Plugins

Plugins are Java/Kotlin main functions. Use com.squareup.stoic.jvmti for debugger features:

// Hook a method
InputEventReceiver.dispatchInputEvent.forEachInvocation {
  println("dispatchInputEvent called")
}

// Scan the heap
for (bitmap in jvmti.instances(Bitmap::class.java)) {
  println("$bitmap: ${bitmap.allocationByteCount} bytes")
}

Create your own plugin:

stoic plugin --new scratch
stoic scratch

Alternatively, use the plugin-sdk to register plugins inside your app.

How It Works

• Debuggable apps: Stoic attaches a JVMTI agent to your process, which starts a server
• Non-debuggable apps: The app-sdk registers a BroadcastReceiver, which starts a server
• Server connection happens via unix domain sockets - no internet permission needed
• Stoic sends plugin APKs to the server, which then loads them via DexClassLoader

See ARCHITECTURE.md.