# Crash Triage

> Diagnose an Xcode/iOS crash log or stack trace to a root-cause hypothesis and file:line without a full-project read.

- Skill: `tristan-hauber/crash-triage` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tristan-hauber/crash-triage`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tristan-hauber/crash-triage/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: Tristan-Hauber (https://skillmd.com/u/tristan-hauber)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/tristan-hauber/crash-triage

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1. If frames show raw addresses, not symbols, say so and stop — ask for a symbolicated export or the `atos` command. Do not guess at unsymbolicated frames.
2. Walk the crashing thread top-down; stop at the first frame in the user's own module (skip libswiftCore, UIKitCore, libobjc, libdispatch, Foundation, SwiftUI internals — note as skipped).
3. Classify first: `SIGABRT` + "Unexpectedly found nil" -> force unwrap; + "Index out of range" -> bounds; `EXC_BAD_ACCESS` -> use-after-free/unsafe pointer/data race; `EXC_BREAKPOINT`/`SIGTRAP` -> runtime trap; NSException -> bad cast/KVC key; watchdog (0x8badf00d) -> main thread blocked at launch/transition, not a traditional crash.
4. Read only the crashing function (`rg -n "func <name>"`) plus its caller if the crashing value is passed in — not the file, not the module.
5. Check: force unwrap on a legitimately-nilable value, off-main-thread mutation, a closure capturing `self` strongly across an async gap, Core Data used across contexts, unchecked `Task` cancellation.
6. Output: 2-4 sentence hypothesis, `file:line`, and a fix or the concrete thing to verify. Reference frame numbers, never paste the full trace.