render-regression-check

name	render-regression-check
description	Diagnose rendering regressions by finding and fixing the earliest broken stage with minimal scope.

Skill: render-regression-check

Use when:

• something used to render correctly and now regressed
• there is a known recent diff/commit window
• a visual regression is available

Goal

Find the smallest changed surface that explains the regression.

Workflow

1. Define:
   • last known good behavior
   • current broken behavior
   • suspect file set / diff if available
2. Classify affected stage:
   • DOM
   • style/cascade
   • layout
   • paint tree
   • host composition
3. Inspect only changed files first.
4. Look for contract breaks across stage boundaries.
5. Fix the source-stage regression, not the last visible symptom.
6. Verify using the smallest deterministic repro.

Do not

• scan unrelated files
• convert a regression fix into a broad cleanup
• skip before/after behavior description

Output contract

1. regressed behavior
2. suspect surface
3. root cause
4. minimal rollback/fix strategy
5. verification

Token discipline

• stay inside the diff unless evidence forces wider inspection