reproduce-first-debuglisted

# Reproduce-First Debugging Force a failing reproduction before any hypothesis, then keep that reproduction forever as a regression test. ## Scope Covers defect investigation from report to logged root cause: gathering trigger data, building a reproduction artifact, bisecting the broken layer boundary, and promoting the reproduction to a permanent test. Does **not** cover: implementing features, reviewing diffs, performance profiling without a functional defect, or fixing a defect whose root cause is already confirmed and evidenced — in that case go straight to the fix. ## Examples ```bash /reproduce-first-debug Promotion code is ignored on the cart page for bundled products ``` ```bash /reproduce-first-debug ABC-1234 ``` ```bash # Also triggers on a bare paste, with no question attached: /reproduce-first-debug TypeError: Cannot read properties of undefined (reading 'total') at CartSummary.vue:42 ``` ## Workflow ```mermaid flowchart TD A[1. Collect trigger data] -->|complete| B[2. Build reproduction artifact] A -->|input missing| A1[Ask for the specific input. STOP.] B -->|artifact fails reproducibly| C[3. Bisect the layer boundary] B -->|cannot reproduce, input missing| A1 B -->|cannot reproduce, inputs present, attempts < 3| B B -->|cannot reproduce after 3 attempts, inputs present| B1[Not reproducible locally. Record attempted vectors, hand back: instrumentation or prod trace. STOP.] C --> D[4. Promote to regression test, commit RED]