What problem does it solve? When you swap a frontend stack — Tailwind to vanilla CSS, a reset-CSS change, a bundler swap — the markup is deliberately rewritten, so a flat pixel diff drowns real regressions in 60-90% noise. This Skill structures migration verification around component bounding boxes and computed-style deltas so only meaningful divergences surface. ## Core Features & Use Cases - Compare mode: Deterministic capture of baseline and variant with pixel diff, per-section bounding boxes, and per-viewport computed-style diff, producing a numeric verdict. - Blind mode: The variant agent never sees baseline pixels and must converge from structural hints and CSD feedback over a fixed round budget, stress-testing the new stack's authoring ergonomics. - Subagent mode: Dispatches a fresh agent to run the comparison and write an unbiased structured verdict inside a longer chain. - Use Case: After porting a page from Tailwind to hand-written CSS, run vlmkit migration compare baseline.html variant.html --output reports/ and inspect the computed-style tables to find missing @media rules instead of chasing pixel noise. ## Quick Start Ask the agent to evaluate whether your Tailwind-to-vanilla-CSS migration is visually equivalent by running vlmkit migration compare on the baseline and variant pages with masked non-deterministic selectors.
