calubecalube/mobile-observability/skills/crash-instrumentation/SKILL.md

crash-instrumentation

Skill116 starsChanged 11 months agoMITView on GitHub

Set up crash instrumentation with actionable context. Use when configuring crash capture, error boundaries, or breadcrumb strategies.

In this repository8 other files it gives its agents.
- CLAUDE.mdCLAUDE.md
- instrumentation-planningSkill
- interaction-latencySkill
- navigation-latencySkill
- network-tracingSkill
- session-replaySkill
- symbolication-setupSkill
- user-journey-trackingSkill

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Limit: Keep last 20-50 breadcrumbs.
line 43

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Files

SKILL.md

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.

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