diff --git a/docs/memory/decisions-log.md b/docs/memory/decisions-log.md
index 2e95327..6deacfc 100644
--- a/docs/memory/decisions-log.md
+++ b/docs/memory/decisions-log.md
@@ -278,6 +278,15 @@ contradict a previous one.
 **Affects:** FuneralFinder stories (title changes), component-registry (V3 = done, V1/V2 = archived), retroactive review (only V3 gets full treatment)
 **Alternatives considered:** Deleting V1/V2 — rejected because user needs them for client walkthroughs.
 
+### D034 — Form error styling should use copper, not red (pending)
+**Date:** 2026-03-29
+**Category:** token
+**Decision:** Pending — form error borders and helper text should use copper (#B0610F) instead of MUI's default red (#BC2F2F). Page-level error messages already use copper as of the grooming pass. Atom-level styling (ToggleButtonGroup error border, TextField/OutlinedInput error border, FormHelperText) still uses `palette.error.main` (red).
+**Rationale:** FA's grief-sensitive context makes aggressive red inappropriate for form validation. D024 established that labels stay neutral on error; extending this principle to borders and helper text creates a fully warm error experience. Page-level error messages already use `var(--fa-color-text-brand)` (copper) — atom-level should match.
+**Recommended approach:** Override `MuiFormHelperText`, `MuiOutlinedInput`, and ToggleButtonGroup error styles in the MUI theme to use copper. Keep `palette.error.main` red for non-form uses (destructive buttons, system alerts).
+**Affects:** src/theme/index.ts, ToggleButtonGroup atom, all form-consuming components
+**Alternatives considered:** Changing `palette.error.main` globally to copper — rejected because destructive action buttons and system alerts may genuinely need red.
+
 ### D033 — Retroactive review uses P0/P1 only, interleaved with new work
 **Date:** 2026-03-27
 **Category:** architecture
diff --git a/docs/reference/retroactive-review-plan.md b/docs/reference/retroactive-review-plan.md
index 47cf359..d61d837 100644
--- a/docs/reference/retroactive-review-plan.md
+++ b/docs/reference/retroactive-review-plan.md
@@ -102,10 +102,11 @@ retained as alternatives.
 ## Phase 4: Cross-cutting concerns
 
 After individual components are clean:
-1. Run `/adapt` on all organisms + ProviderCard/VenueCard (responsive check)
-2. Run `/typeset` across a representative sample of each tier
-3. Run `/preflight` to verify the full codebase
-4. Commit all fixes
+1. **Form error colour normalisation (D034):** Override MuiFormHelperText, MuiOutlinedInput, and ToggleButtonGroup error styles in `src/theme/index.ts` to use copper instead of red. Keep `palette.error.main` red for non-form uses. This unifies atom-level error styling with the page-level copper already applied in the wizard grooming pass.
+2. Run `/adapt` on all organisms + ProviderCard/VenueCard (responsive check)
+3. Run `/typeset` across a representative sample of each tier
+4. Run `/preflight` to verify the full codebase
+5. Commit all fixes
 
 **Estimated effort:** 0.5 session.