diff --git a/ci-baseline.json b/ci-baseline.json
index c17a9dc9d..9e3a52edc 100644
--- a/ci-baseline.json
+++ b/ci-baseline.json
@@ -1,7 +1,7 @@
 {
   "$schema": "./ci-baseline.schema.json",
   "policy": "ratchet: counts are upper bounds — current or lower passes; exceeding blocks push. Update via `pnpm baseline:ci` after a genuine reduction.",
-  "recordedAt": "2026-04-19",
+  "recordedAt": "2026-04-21",
   "lint": {
     "errors": 0,
     "warnings": 247
@@ -10,8 +10,8 @@
     "errors": 0
   },
   "test": {
-    "failedFiles": 1,
-    "failedTests": 1,
+    "failedFiles": 0,
+    "failedTests": 0,
     "runtimeErrors": 0
   }
 }
diff --git a/src/interactive-os/engine/shallow.ts b/src/interactive-os/engine/shallow.ts
index 208eaacaf..1cccd11c8 100644
--- a/src/interactive-os/engine/shallow.ts
+++ b/src/interactive-os/engine/shallow.ts
@@ -4,31 +4,36 @@
  *
  * Supports plain objects, arrays, `Map`, and `Set`. Matches Zustand semantics.
  */
-export function shallow<T>(a: T, b: T): boolean {
-  if (Object.is(a, b)) return true
-  if (typeof a !== 'object' || a === null || typeof b !== 'object' || b === null) return false
-
-  if (a instanceof Map && b instanceof Map) {
-    if (a.size !== b.size) return false
-    for (const [k, v] of a) {
-      if (!b.has(k) || !Object.is(v, b.get(k))) return false
-    }
-    return true
+function shallowMap(a: Map<unknown, unknown>, b: Map<unknown, unknown>): boolean {
+  if (a.size !== b.size) return false
+  for (const [k, v] of a) {
+    if (!b.has(k) || !Object.is(v, b.get(k))) return false
   }
-  if (a instanceof Set && b instanceof Set) {
-    if (a.size !== b.size) return false
-    for (const v of a) {
-      if (!b.has(v)) return false
-    }
-    return true
+  return true
+}
+
+function shallowSet(a: Set<unknown>, b: Set<unknown>): boolean {
+  if (a.size !== b.size) return false
+  for (const v of a) {
+    if (!b.has(v)) return false
   }
+  return true
+}
 
-  const keysA = Object.keys(a as object)
-  const keysB = Object.keys(b as object)
-  if (keysA.length !== keysB.length) return false
+function shallowObject(a: object, b: object): boolean {
+  const keysA = Object.keys(a)
+  if (keysA.length !== Object.keys(b).length) return false
   for (const key of keysA) {
     if (!Object.prototype.hasOwnProperty.call(b, key)) return false
     if (!Object.is((a as Record<string, unknown>)[key], (b as Record<string, unknown>)[key])) return false
   }
   return true
 }
+
+export function shallow<T>(a: T, b: T): boolean {
+  if (Object.is(a, b)) return true
+  if (typeof a !== 'object' || a === null || typeof b !== 'object' || b === null) return false
+  if (a instanceof Map && b instanceof Map) return shallowMap(a, b)
+  if (a instanceof Set && b instanceof Set) return shallowSet(a, b)
+  return shallowObject(a as object, b as object)
+}