fw-12 step 03 — mini-devtools, without perturbing

Tasks

  1. Instrument your fw-02/fw-05 runtime to display: component tree, render counts, state changes, network requests, performance marks.
  2. Do not perturb what you measure. Verify: no strong references retained to component instances (a bi-04 leak), no observable state writes that trigger re-renders, overhead low enough that the timings remain true. Measure the overhead and state it.
  3. Deliberately build the leaking version first — retain every instance — and find it in a heap snapshot.
  4. Study the Chrome DevTools Protocol. Confirm that DevTools is a protocol client, and that automation uses the same protocol.
  5. Put one thing in CI. Pick a signal you currently inspect manually — trace-derived long tasks, CSS coverage, an accessibility-tree assertion, or composited layer count — and wire it into a pipeline as a regression guard.

Done when

  • Devtools layer working, overhead measured
  • Leaking version reproduced and fixed
  • One DevTools-derived signal running in CI