diff --git a/.prettierignore b/.prettierignore
index b89bf460d..9d07b6019 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -15,6 +15,14 @@ target/
 # Auto-generated by @tanstack/router-plugin.
 apps/web/src/routeTree.gen.ts
 
+# op-design-lint TS-oracle parity goldens — regenerated by
+# `tools/dump-diagnostics-golden.ts` via `JSON.stringify(value, null, 2)`,
+# which keeps 4-element arrays multi-line. oxfmt's `printWidth: 100`
+# inlines them, causing the CI drift guard (rust-check.yml: "Fail on
+# golden drift") to red on every push. Keep these byte-identical to
+# what the TS oracle emits.
+crates/op-design-lint/tests/fixtures/golden/
+
 # Local scratch / tutorial outputs (not part of the codebase; users won't have these dirs).
 .baoyu-skills/
 xhs-images/
diff --git a/crates/op-design-lint/tests/fixtures/golden/edge-section-padding.json b/crates/op-design-lint/tests/fixtures/golden/edge-section-padding.json
index 7ced3d384..9158694df 100644
--- a/crates/op-design-lint/tests/fixtures/golden/edge-section-padding.json
+++ b/crates/op-design-lint/tests/fixtures/golden/edge-section-padding.json
@@ -5,7 +5,12 @@
     "severity": "warning",
     "property": "padding",
     "currentValue": null,
-    "suggestedValue": [0, 16, 0, 16],
+    "suggestedValue": [
+      0,
+      16,
+      0,
+      16
+    ],
     "reason": "mobile root has 0 horizontal padding while 2 content section(s) glue text/icon to screen edge"
   }
 ]
diff --git a/crates/op-design-lint/tests/fixtures/golden/stacked-horizontal-padding.json b/crates/op-design-lint/tests/fixtures/golden/stacked-horizontal-padding.json
index 066f706c1..c42bd069d 100644
--- a/crates/op-design-lint/tests/fixtures/golden/stacked-horizontal-padding.json
+++ b/crates/op-design-lint/tests/fixtures/golden/stacked-horizontal-padding.json
@@ -4,7 +4,12 @@
     "category": "stacked-horizontal-padding",
     "severity": "info",
     "property": "padding",
-    "currentValue": [0, 24, 0, 24],
+    "currentValue": [
+      0,
+      24,
+      0,
+      24
+    ],
     "suggestedValue": null,
     "reason": "section h-padding [24/24] stacks with root h-padding [16/16] — combined gutter 40/40"
   }