diff --git a/pkg/workloadmanager/sandbox_helper.go b/pkg/workloadmanager/sandbox_helper.go
index 17d565bc..36b392dd 100644
--- a/pkg/workloadmanager/sandbox_helper.go
+++ b/pkg/workloadmanager/sandbox_helper.go
@@ -27,12 +27,18 @@ import (
 )
 
 func buildSandboxPlaceHolder(sandboxCR *sandboxv1alpha1.Sandbox, entry *sandboxEntry) *types.SandboxInfo {
+	var expiresAt time.Time
+	if sandboxCR.Spec.Lifecycle.ShutdownTime != nil {
+		expiresAt = sandboxCR.Spec.Lifecycle.ShutdownTime.Time
+	} else {
+		expiresAt = time.Now().Add(DefaultSandboxTTL)
+	}
 	return &types.SandboxInfo{
 		Kind:             entry.Kind,
 		SessionID:        entry.SessionID,
 		SandboxNamespace: sandboxCR.GetNamespace(),
 		Name:             sandboxCR.GetName(),
-		ExpiresAt:        time.Now().Add(DefaultSandboxTTL),
+		ExpiresAt:        expiresAt,
 		Status:           "creating",
 	}
 }
diff --git a/pkg/workloadmanager/sandbox_helper_test.go b/pkg/workloadmanager/sandbox_helper_test.go
index c58ade10..7ff9e40d 100644
--- a/pkg/workloadmanager/sandbox_helper_test.go
+++ b/pkg/workloadmanager/sandbox_helper_test.go
@@ -30,9 +30,132 @@ import (
 
 const sandboxHelperTestPodIP = "10.0.0.1"
 
-// Note: TestBuildSandboxPlaceHolder and TestBuildSandboxPlaceHolder_CodeInterpreter
-// removed - they only verified that struct fields match input parameters, which is
-// trivial field copying behavior.
+func TestBuildSandboxPlaceHolder_TableDriven(t *testing.T) {
+	now := time.Now()
+
+	tests := []struct {
+		name         string
+		setupSandbox func() *sandboxv1alpha1.Sandbox
+		entry        *sandboxEntry
+		validate     func(t *testing.T, result *types.SandboxInfo)
+	}{
+		{
+			name: "no ShutdownTime falls back to DefaultSandboxTTL",
+			setupSandbox: func() *sandboxv1alpha1.Sandbox {
+				return &sandboxv1alpha1.Sandbox{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-sandbox",
+						Namespace: "default",
+					},
+				}
+			},
+			entry: &sandboxEntry{
+				Kind:      types.SandboxKind,
+				SessionID: "session-123",
+			},
+			validate: func(t *testing.T, result *types.SandboxInfo) {
+				expected := now.Add(DefaultSandboxTTL)
+				assert.WithinDuration(t, expected, result.ExpiresAt, 2*time.Second)
+				assert.Equal(t, "creating", result.Status)
+				assert.Equal(t, "session-123", result.SessionID)
+			},
+		},
+		{
+			name: "ShutdownTime set to 24h is used as ExpiresAt",
+			setupSandbox: func() *sandboxv1alpha1.Sandbox {
+				shutdownTime := now.Add(24 * time.Hour)
+				return &sandboxv1alpha1.Sandbox{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-sandbox",
+						Namespace: "default",
+					},
+					Spec: sandboxv1alpha1.SandboxSpec{
+						Lifecycle: sandboxv1alpha1.Lifecycle{
+							ShutdownTime: &metav1.Time{Time: shutdownTime},
+						},
+					},
+				}
+			},
+			entry: &sandboxEntry{
+				Kind:      types.SandboxKind,
+				SessionID: "session-456",
+			},
+			validate: func(t *testing.T, result *types.SandboxInfo) {
+				expected := now.Add(24 * time.Hour)
+				assert.Equal(t, expected, result.ExpiresAt)
+			},
+		},
+		{
+			name: "ShutdownTime set to 30m overrides DefaultSandboxTTL",
+			setupSandbox: func() *sandboxv1alpha1.Sandbox {
+				shutdownTime := now.Add(30 * time.Minute)
+				return &sandboxv1alpha1.Sandbox{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "short-sandbox",
+						Namespace: "default",
+					},
+					Spec: sandboxv1alpha1.SandboxSpec{
+						Lifecycle: sandboxv1alpha1.Lifecycle{
+							ShutdownTime: &metav1.Time{Time: shutdownTime},
+						},
+					},
+				}
+			},
+			entry: &sandboxEntry{
+				Kind:      types.SandboxClaimsKind,
+				SessionID: "session-789",
+			},
+			validate: func(t *testing.T, result *types.SandboxInfo) {
+				expected := now.Add(30 * time.Minute)
+				assert.Equal(t, expected, result.ExpiresAt)
+				// Must NOT be 8h (DefaultSandboxTTL)
+				assert.True(t, result.ExpiresAt.Before(now.Add(DefaultSandboxTTL)),
+					"ExpiresAt should be 30m, not the 8h default")
+			},
+		},
+		{
+			name: "warm-pool path: ShutdownTime set on simpleSandbox reflects MaxSessionDuration",
+			setupSandbox: func() *sandboxv1alpha1.Sandbox {
+				// Simulates the simpleSandbox built by the warm-pool CodeInterpreter path
+				// after the fix in workload_builder.go sets ShutdownTime from MaxSessionDuration.
+				shutdownTime := now.Add(24 * time.Hour)
+				return &sandboxv1alpha1.Sandbox{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "default",
+						Name:      "ci-warmpool-abc",
+						Labels: map[string]string{
+							SessionIdLabelKey: "session-wp-001",
+						},
+					},
+					Spec: sandboxv1alpha1.SandboxSpec{
+						Lifecycle: sandboxv1alpha1.Lifecycle{
+							ShutdownTime: &metav1.Time{Time: shutdownTime},
+						},
+					},
+				}
+			},
+			entry: &sandboxEntry{
+				Kind:      types.SandboxClaimsKind,
+				SessionID: "session-wp-001",
+			},
+			validate: func(t *testing.T, result *types.SandboxInfo) {
+				expected := now.Add(24 * time.Hour)
+				assert.Equal(t, expected, result.ExpiresAt,
+					"warm-pool placeholder ExpiresAt must reflect MaxSessionDuration, not the 8h default")
+				assert.Equal(t, "creating", result.Status)
+				assert.Equal(t, types.SandboxClaimsKind, result.Kind)
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sandbox := tt.setupSandbox()
+			result := buildSandboxPlaceHolder(sandbox, tt.entry)
+			tt.validate(t, result)
+		})
+	}
+}
 
 func TestBuildSandboxInfo_TableDriven(t *testing.T) {
 	now := time.Now()
diff --git a/pkg/workloadmanager/workload_builder.go b/pkg/workloadmanager/workload_builder.go
index e7d06dde..dc426d77 100644
--- a/pkg/workloadmanager/workload_builder.go
+++ b/pkg/workloadmanager/workload_builder.go
@@ -351,6 +351,10 @@ func buildSandboxByCodeInterpreter(namespace string, codeInterpreterName string,
 				},
 			},
 		}
+		if codeInterpreterObj.Spec.MaxSessionDuration != nil {
+			shutdownTime := metav1.NewTime(time.Now().Add(codeInterpreterObj.Spec.MaxSessionDuration.Duration))
+			simpleSandbox.Spec.Lifecycle.ShutdownTime = &shutdownTime
+		}
 		sandboxEntry.Kind = types.SandboxClaimsKind
 		return simpleSandbox, sandboxClaim, sandboxEntry, nil
 	}