diff --git a/test/e2e/features/cos_object_collision_and_adoption.feature b/test/e2e/features/cos_object_collision_and_adoption.feature
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+++ b/test/e2e/features/cos_object_collision_and_adoption.feature
@@ -0,0 +1,363 @@
+@BoxcutterRuntime
+Feature: ClusterObjectSet object collision and adoption
+
+  As an OLM user applying a ClusterObjectSet directly, I want the revision's
+  collisionProtection setting to control whether it refuses to manage objects
+  that already exist (reporting ObjectCollision) or adopts them, so that I can
+  choose how aggressively a revision takes ownership of pre-existing objects.
+
+  Background:
+    Given OLM is available
+
+  # ---------------------------------------------------------------------------
+  # Collisions: the revision refuses to take ownership (Ready=False/ObjectCollision)
+  # ---------------------------------------------------------------------------
+
+  Scenario: Prevent reports ObjectCollision for a pre-existing unowned object
+    Given namespace "${TEST_NAMESPACE}" is available
+    And resource is applied
+      """
+      apiVersion: v1
+      kind: ConfigMap
+      metadata:
+        name: shared-cm
+        namespace: ${TEST_NAMESPACE}
+      data:
+        k: pre-existing
+      """
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: ${COS_NAME}
+      spec:
+        lifecycleState: Active
+        group: ${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: managed
+        revision: 1
+      """
+    Then ClusterObjectSet "${COS_NAME}" reports Ready as False with Reason ObjectCollision and Message includes:
+    """
+      Cannot take ownership of 1 object(s) in phase "resources" because they are owned by another controller or already exist.
+    """
+    And resource "configmap/shared-cm" matches
+      """
+      data:
+        k: pre-existing
+      """
+
+  Scenario: Prevent reports ObjectCollision for an object owned by another revision
+    Given namespace "${TEST_NAMESPACE}" is available
+    And ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: owner-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: owner-${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: owned-by-owner
+        revision: 1
+      """
+    And ClusterObjectSet "owner-${TEST_NAMESPACE}" reports Ready as True with Reason AllObjectsReady
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: main-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: main-${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: contested
+        revision: 1
+      """
+    Then ClusterObjectSet "main-${TEST_NAMESPACE}" reports Ready as False with Reason ObjectCollision and Message includes:
+    """
+      Cannot take ownership of 1 object(s) in phase "resources" because they are owned by another controller or already exist.
+    """
+
+  Scenario: IfNoController reports ObjectCollision for an object owned by another revision
+    Given namespace "${TEST_NAMESPACE}" is available
+    And ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: owner-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: owner-${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: owned-by-owner
+        revision: 1
+      """
+    And ClusterObjectSet "owner-${TEST_NAMESPACE}" reports Ready as True with Reason AllObjectsReady
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: main-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: main-${NAME}
+        collisionProtection: IfNoController
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: contested
+        revision: 1
+      """
+    Then ClusterObjectSet "main-${TEST_NAMESPACE}" reports Ready as False with Reason ObjectCollision and Message includes:
+    """
+      Cannot take ownership of 1 object(s) in phase "resources" because they are owned by another controller or already exist.
+    """
+
+  # ---------------------------------------------------------------------------
+  # Adoption: the revision takes ownership (Ready=True/AllObjectsReady)
+  # ---------------------------------------------------------------------------
+
+  Scenario: IfNoController adopts a pre-existing unowned object
+    Given namespace "${TEST_NAMESPACE}" is available
+    And resource is applied
+      """
+      apiVersion: v1
+      kind: ConfigMap
+      metadata:
+        name: shared-cm
+        namespace: ${TEST_NAMESPACE}
+      data:
+        k: pre-existing
+      """
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: ${COS_NAME}
+      spec:
+        lifecycleState: Active
+        group: ${NAME}
+        collisionProtection: IfNoController
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: managed
+        revision: 1
+      """
+    Then ClusterObjectSet "${COS_NAME}" reports Ready as True with Reason AllObjectsReady
+    And resource "configmap/shared-cm" matches
+      """
+      data:
+        k: managed
+      """
+
+  Scenario: None adopts a pre-existing unowned object
+    Given namespace "${TEST_NAMESPACE}" is available
+    And resource is applied
+      """
+      apiVersion: v1
+      kind: ConfigMap
+      metadata:
+        name: shared-cm
+        namespace: ${TEST_NAMESPACE}
+      data:
+        k: pre-existing
+      """
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: ${COS_NAME}
+      spec:
+        lifecycleState: Active
+        group: ${NAME}
+        collisionProtection: None
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: managed
+        revision: 1
+      """
+    Then ClusterObjectSet "${COS_NAME}" reports Ready as True with Reason AllObjectsReady
+    And resource "configmap/shared-cm" matches
+      """
+      data:
+        k: managed
+      """
+
+  Scenario: None adopts an object owned by another revision
+    Given namespace "${TEST_NAMESPACE}" is available
+    And ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: owner-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: owner-${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: owned-by-owner
+        revision: 1
+      """
+    And ClusterObjectSet "owner-${TEST_NAMESPACE}" reports Ready as True with Reason AllObjectsReady
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: main-${TEST_NAMESPACE}
+      spec:
+        lifecycleState: Active
+        group: main-${NAME}
+        collisionProtection: None
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: contested
+        revision: 1
+      """
+    Then ClusterObjectSet "main-${TEST_NAMESPACE}" reports Ready as True with Reason AllObjectsReady
+    And resource "configmap/shared-cm" matches
+      """
+      data:
+        k: contested
+      """
+
+  # ---------------------------------------------------------------------------
+  # Recovery: a collision clears once the conflicting object is removed
+  # ---------------------------------------------------------------------------
+
+  Scenario: ClusterObjectSet recovers from ObjectCollision once the conflicting object is removed
+    Given namespace "${TEST_NAMESPACE}" is available
+    And resource is applied
+      """
+      apiVersion: v1
+      kind: ConfigMap
+      metadata:
+        name: shared-cm
+        namespace: ${TEST_NAMESPACE}
+      data:
+        k: pre-existing
+      """
+    When ClusterObjectSet is applied
+      """
+      apiVersion: olm.operatorframework.io/v1
+      kind: ClusterObjectSet
+      metadata:
+        name: ${COS_NAME}
+      spec:
+        lifecycleState: Active
+        group: ${NAME}
+        collisionProtection: Prevent
+        phases:
+        - name: resources
+          objects:
+          - object:
+              apiVersion: v1
+              kind: ConfigMap
+              metadata:
+                name: shared-cm
+                namespace: ${TEST_NAMESPACE}
+              data:
+                k: managed
+        revision: 1
+      """
+    Then ClusterObjectSet "${COS_NAME}" reports Ready as False with Reason ObjectCollision and Message includes:
+    """
+      Cannot take ownership of 1 object(s) in phase "resources" because they are owned by another controller or already exist.
+    """
+    When resource "configmap/shared-cm" is removed
+    And ClusterObjectSet "${COS_NAME}" reconciliation is triggered
+    Then ClusterObjectSet "${COS_NAME}" reports Ready as True with Reason AllObjectsReady
+    And resource "configmap/shared-cm" matches
+      """
+      data:
+        k: managed
+      """