The lever the plan deliberately held back, applied now that there is evidence it is needed. Better failure messages and a wider assertion timeout were not enough. Measured on this branch, same commit, same machine. Two parallel runs each failed 3 of 155, and not the same three: password-reset and admin-inventory-filters in one, admin-email-settings, admin-inventory-filters and resend-verification in the next. All 16 tests from those three specs then passed when run serially, and the full suite passed 155 of 155 twice in a row. Failures that move between runs of identical code are contention, not defects — specs asserting over tables other specs are concurrently writing to. The cost is about three minutes, roughly one minute parallel against 3.9 and 4.0 serially. A red run that means something is worth three minutes; the previous state was a suite whose result nobody could act on, which is what #245 had to skip a real test to work around. If that time is ever needed back, the cheaper fix is giving each worker its own database rather than raising this number and reopening #241. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>