diff --git a/docs/superpowers/specs/2026-08-20-error-boundary-design.md b/docs/superpowers/specs/2026-08-20-error-boundary-design.md
index 1b325db..0e358b0 100644
--- a/docs/superpowers/specs/2026-08-20-error-boundary-design.md
+++ b/docs/superpowers/specs/2026-08-20-error-boundary-design.md
@@ -2,7 +2,7 @@
 
 **Issue:** [#62 — No React error boundary](https://gitea.bermudalamb.synology.me/bermudalamb/redefined-designs/issues/62)
 **Date:** 2026-08-20
-**Status:** Approved
+**Status:** Implemented
 
 ## Goal
 
@@ -148,6 +148,16 @@ Assertions are on the three distinct fallback titles, so a test cannot pass beca
 
 The new frontend files use deep imports from `antd/es/*`, which is this project's documented convention and the style every recently-added file follows. Not `antd/lib/*`: #65 records that as the mistake which loads a second React context and breaks `ConfigProvider`. The nine files still using the `antd` barrel are #65's business, not this change's.
 
+## Corrections found during implementation
+
+Two things this design got wrong, recorded here rather than left for the next reader to rediscover.
+
+**antd's `Result` renders its title as a plain `<div>`, with no heading semantics.** This design specified both a `Result` with a string title and end-to-end assertions using `getByRole('heading')` — two requirements that contradict each other, so the tests could never have passed as written. The fix was to give the title a real heading rather than to loosen the assertion: a page whose entire content is an error message, with nothing carrying heading semantics, offers a screen-reader user navigating by headings nothing at all to find. `ErrorFallback` now wraps the title in `Typography.Title`, and the assertion stands as it was.
+
+**`import.meta.env` had no ambient type declaration.** Nothing in this application had used `import.meta.env` before — the only Vite environment gating lived in `vite.config.ts` — so `tsc` rejected the `DEV` check outright with TS2339. `frontend/src/vite-env.d.ts` was added, which is the standard one-line Vite reference and pulls in no new dependency.
+
+One thing the design flagged as a risk did not materialise: Vite's error overlay never interfered with the Playwright run, so `vite.config.ts` was left alone.
+
 ## Out of scope
 
 Error reporting to an external service, persisting errors, alerting, and a frontend unit-test suite — the last belongs to #72, which already owns it.