Step 5 — Principal Engineer Review

Answer in writing.

1. A designer requires a modal backdrop your team says <dialog> cannot produce. Walk through how you verify the claim, what you propose, and what you would accept as a reason to hand-roll.

2. Your design system ships <Button> as a styled div with role="button". It is used by 40 teams. What is the blast radius of fixing it, what is the migration strategy, and what do you do in the meantime?

3. An engineer argues semantic HTML is "verbose boilerplate that hurts bundle size". You have the measurement from Step 1. Write the review comment — persuasive, not smug, and correct about what the numbers do and do not show.

4. Your automated accessibility audit reports zero violations on a page built from div soup. Explain to a PM why the audit is not evidence, and propose what you would gate on instead.

5. Given the dirty-value-flag finding, audit your test strategy. Which existing tests are lying to you? What is the general rule you would adopt about synthetic versus real interaction, and what does it cost in suite runtime?

6. Your team wants a shared useModal() hook wrapping a custom implementation. Specify the API so that native <dialog> can be swapped in later without a breaking change. What must the API not expose?

7. Web Components are proposed for design-system primitives so three frameworks can share them. Argue for and against. What does shadow DOM cost you at the accessibility boundary specifically?

8. Custom control inventories depreciate as the platform gains capabilities. Design the standing process that catches this — who reviews what, how often, and what triggers a migration rather than a note?

9. A legacy application is div soup throughout. You cannot rewrite it. Give a prioritised remediation plan and say how you would measure progress in something other than audit score.

10. Argue the strongest case against this module's thesis. Where does "prefer platform primitives" genuinely fail, and what would you want to see before overriding it?

Record

Answers in RESULTS.md. Questions 2, 6 and 8 are natural ADRs for ../fe-00-roadmap/docs/decisions/ — question 2 in particular, since reversibility and migration are the whole substance of it.