crash-instrumentation

Crash Instrumentation

Capture crashes with the context needed to debug them.

Core Principle

A crash report without context is useless. Every crash should include:

Context	Why	Example
screen	Where it happened	"CheckoutScreen"
job_name	What user was doing	"checkout"
job_step	Where in the flow	"payment"
breadcrumbs	What led here	Last 20 user actions
app_version	Release correlation	"1.2.3"
user_segment	Who's affected	"premium", "trial"

Breadcrumb Strategy

Breadcrumbs are the trail leading to a crash. Capture:

Category	What to Log	Example
navigation	Screen transitions	"HomeScreen → CartScreen"
user	Taps, inputs, gestures	"Tapped checkout button"
network	API calls (not payloads)	"POST /api/orders started"
state	Key state changes	"Cart updated: 3 items"
error	Non-fatal errors	"Retry #2 for payment"

Limit: Keep last 20-50 breadcrumbs. More is noise.

Error Boundaries

Catch errors before they crash the app:

// iOS - capture context before crash
func captureError(_ error: Error, screen: String, job: String?) {
    Observability.captureError(error, context: [
        "screen": screen,
        "job_name": job ?? "unknown",
        "session_duration": sessionDuration(),
        "memory_pressure": memoryPressure()
    ])
}

// Android - uncaught exception handler
Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
    Observability.captureError(throwable, mapOf(
        "thread" to thread.name,
        "screen" to currentScreen,
        "job_name" to currentJob
    ))
    previousHandler?.uncaughtException(thread, throwable)
}

What NOT to Attach

Don't	Why
Full stack traces in breadcrumbs	Redundant, SDK captures this
User input text	PII risk
Full request/response bodies	Size limits, PII
Entire app state	Unbounded, noise

Crash Types to Handle

Platform	Type	Instrumentation
iOS	EXC_BAD_ACCESS	Breadcrumbs, memory context
iOS	SIGKILL (watchdog)	Background task tracking
Android	ANR	Main thread breadcrumbs
Android	OutOfMemoryError	Memory tracking
React Native	JS exceptions	Error boundaries

Implementation

See references/crash-reporting.md for:

• Platform-specific crash capture setup
• Breadcrumb implementation patterns
• Vendor SDK configuration

See skills/symbolication-setup for readable stack traces.