diff --git a/.codex/skills/mission-core-product-ui/SKILL.md b/.codex/skills/mission-core-product-ui/SKILL.md
index 5847df1..ca1b8a5 100644
--- a/.codex/skills/mission-core-product-ui/SKILL.md
+++ b/.codex/skills/mission-core-product-ui/SKILL.md
@@ -66,6 +66,14 @@ Keep product grammar stable without forcing one layout:
 
 - Reuse the canonical shell, controls, states, icons, focus, motion, and
   responsive behavior.
+- Never add decorative perimeter borders, outlines, inset rings, or persistent
+  edge strokes to Mission Core cards, panels, topology nodes, telemetry blocks,
+  task stages, or LAB content surfaces. Separate product hierarchy with
+  approved surface tones, spacing, typography, and elevation.
+- Preserve canonical keyboard focus indicators and accessibility outlines from
+  the Design Guideline. The no-outline rule applies to decoration, never to
+  focus visibility, data-visualization grids, or a necessary structural
+  divider.
 - Change composition when the operator job, primary entity, lifecycle, or
   action model changes materially.
 - Do not treat the LAB template as the default for non-LAB work.
@@ -199,7 +207,10 @@ Do not turn the product UI into a duplicate Ops report.
 Before handoff:
 
 1. Search the changed product UI for raw local controls, hard-coded product
-   colors, temporary copy, gate/checklist UI, and per-LAB page branches.
+   colors, decorative perimeter borders/outlines, temporary copy,
+   gate/checklist UI, and per-LAB page branches. Justify every remaining
+   `border`, `outline`, or inset `box-shadow` as a canonical focus state,
+   data-visualization grid, or necessary structural divider.
 2. Verify every changed or new bounded `ENNResult.tsx` uses
    `LaboratorySummary`, `LaboratoryEvidence`, and `LaboratoryResultSummary`
    without raw canonical report markup.