investigate

What problem does it solve? Debugging often devolves into guessing and symptom-patching, which creates whack-a-mole bugs that resurface later. This Skill enforces a disciplined five-phase debugging workflow that finds the actual root cause before any fix is applied, then proves the fix with a regression test. ## Core Features & Use Cases - Root Cause Investigation: Collects symptoms, traces code paths with Grep and Read, checks recent git history, and reproduces the bug before forming any hypothesis. - Hypothesis Testing with Guardrails: Matches bugs against known patterns (race conditions, null propagation, state corruption, config drift), applies a 3-strike escalation rule, and locks edit scope to the affected directory to prevent scope creep. - Verified Fixes with Regression Tests: Requires a test that fails without the fix and passes with it, runs the full test suite, and outputs a structured debug report with file:line evidence. - Use Case: A user reports "login intermittently fails in production." The Skill traces the auth flow, checks recent commits to the session module, identifies a race condition in token refresh, confirms it with a temporary log, applies a minimal fix, and adds a regression test. ## Quick Start Ask the assistant to investigate why a specific error or unexpected behavior is happening and find the root cause before fixing it.