Agent skill · data analytics · secondsky
root-cause-tracing
Systematically trace bugs backward through call stack to find original trigger. Use when errors occur deep in execution and you need to trace back to find the original trigger.
Why this skill is useful
Provides detailed domain-specific knowledge on tracing bugs through call stacks, which the AI wouldn't reliably generate on its own.
What it needs
About 2k tokens when loaded. Last updated 2026-08-06. 204 stars on the source repository.
What this skill does
Root Cause Tracing Overview Bugs often manifest deep in the call stack (git init in wrong directory, file created in wrong location, database opened with wrong path). Your instinct is to fix where the error appears, but that's treating a symptom. Core principle: Trace backward through the call chain until you find the original trigger, then fix at the source. When to Use Use when: Error happens deep in execution (not at entry point) Stack trace shows long call chain Unclear where invalid data originated Need to find which test/code triggers the problem The Tracing Process 1. Observe the Symptom 2. Find Immediate Cause What code directly causes this? 3. Ask: What Called This? 4. Keep Tracing Up What value was passed? projectDir = '' (empty string!) Empty string as cwd resolves to process.cwd() That's the source code directory! 5. Find Original Trigger Where did empty string come from? Adding Stack Traces When you can't trace manually, add instrumentation: Critical: Use console.error() in tests (not logger - may not show) Run and capture: Analyze stack traces: Look for test file names Find the line number triggering the call Identify the pattern (same test? same parameter?) Finding Which Test Causes Pollution If something appears during tests but you don't know which test: Use the bisection script to run tests one-by-one: Runs tests one-by-one, stops at first polluter. Real Example: Empty projectDir Symptom: .git created in packages/core/ (source code) Trace chain: 1. git init runs in process.cwd() ← empty cwd parameter 2. WorktreeManager called with empty projectDir 3. Session.create() passed empty string 4. Test accessed context.tempDir before beforeEach 5. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills secondsky/root-cause-tracing