diff --git a/crates/openshell-driver-kubernetes/src/driver.rs b/crates/openshell-driver-kubernetes/src/driver.rs
index 909568302..bdab5d120 100644
--- a/crates/openshell-driver-kubernetes/src/driver.rs
+++ b/crates/openshell-driver-kubernetes/src/driver.rs
@@ -1298,17 +1298,6 @@ fn sandbox_to_k8s_spec(
 ) -> serde_json::Value {
     let mut root = serde_json::Map::new();
 
-    // Determine early whether the user provided custom volumeClaimTemplates.
-    // When they haven't, we inject a default workspace VCT and corresponding
-    // init container + volume mount so sandbox data persists.  We need this
-    // flag before building the podTemplate because the workspace persistence
-    // transforms are applied inside sandbox_template_to_k8s.
-    let user_has_vct = spec
-        .and_then(|s| s.template.as_ref())
-        .and_then(|t| platform_config_struct(t, "volume_claim_templates"))
-        .is_some();
-    let inject_workspace = !user_has_vct;
-
     if let Some(spec) = spec {
         let pod_env = spec_pod_env(Some(spec));
         if let Some(template) = spec.template.as_ref() {
@@ -1318,7 +1307,7 @@ fn sandbox_to_k8s_spec(
                     template,
                     driver_gpu_requirements(spec.resource_requirements.as_ref()),
                     &pod_env,
-                    inject_workspace,
+                    true,
                     params,
                 ),
             );
@@ -1328,22 +1317,13 @@ fn sandbox_to_k8s_spec(
                     serde_json::json!(template.agent_socket_path),
                 );
             }
-            if let Some(volume_templates) =
-                platform_config_struct(template, "volume_claim_templates")
-            {
-                root.insert("volumeClaimTemplates".to_string(), volume_templates);
-            }
         }
     }
 
-    // Inject the default workspace volumeClaimTemplate when the user didn't
-    // provide their own.
-    if inject_workspace {
-        root.insert(
-            "volumeClaimTemplates".to_string(),
-            default_workspace_volume_claim_templates(params.workspace_default_storage_size),
-        );
-    }
+    root.insert(
+        "volumeClaimTemplates".to_string(),
+        default_workspace_volume_claim_templates(params.workspace_default_storage_size),
+    );
 
     // podTemplate is required by the Kubernetes CRD - ensure it's always present
     if !root.contains_key("podTemplate") {
@@ -1354,7 +1334,7 @@ fn sandbox_to_k8s_spec(
                 &SandboxTemplate::default(),
                 driver_gpu_requirements(spec.and_then(|s| s.resource_requirements.as_ref())),
                 &pod_env,
-                inject_workspace,
+                true,
                 params,
             ),
         );
diff --git a/crates/openshell-server/src/compute/mod.rs b/crates/openshell-server/src/compute/mod.rs
index fec29f0c4..3a92cd209 100644
--- a/crates/openshell-server/src/compute/mod.rs
+++ b/crates/openshell-server/src/compute/mod.rs
@@ -1666,8 +1666,8 @@ fn extract_typed_resources(
 }
 
 /// Build the opaque `platform_config` Struct from platform-specific public
-/// template fields (`runtime_class_name`, annotations, `volume_claim_templates`)
-/// plus any resource fields beyond CPU/memory.
+/// template fields (`runtime_class_name`, annotations) plus any resource fields
+/// beyond CPU/memory.
 fn build_platform_config(template: &SandboxTemplate) -> Option<prost_types::Struct> {
     use prost_types::{Struct, Value, value::Kind};
 
@@ -1705,16 +1705,6 @@ fn build_platform_config(template: &SandboxTemplate) -> Option<prost_types::Stru
         );
     }
 
-    // Pass through the raw volume_claim_templates Struct as a nested value.
-    if let Some(ref vct) = template.volume_claim_templates {
-        fields.insert(
-            "volume_claim_templates".to_string(),
-            Value {
-                kind: Some(Kind::StructValue(vct.clone())),
-            },
-        );
-    }
-
     // Invert: the public API uses `user_namespaces: true` (positive sense)
     // while the K8s driver expects `host_users: false` (K8s convention).
     // The driver inverts this back via `!host_users` to resolve the final
diff --git a/crates/openshell-server/src/grpc/validation.rs b/crates/openshell-server/src/grpc/validation.rs
index 09e9f1cad..0b3548b06 100644
--- a/crates/openshell-server/src/grpc/validation.rs
+++ b/crates/openshell-server/src/grpc/validation.rs
@@ -206,14 +206,6 @@ fn validate_sandbox_template(tmpl: &SandboxTemplate) -> Result<(), Status> {
             )));
         }
     }
-    if let Some(ref s) = tmpl.volume_claim_templates {
-        let size = s.encoded_len();
-        if size > MAX_TEMPLATE_STRUCT_SIZE {
-            return Err(Status::invalid_argument(format!(
-                "template.volume_claim_templates serialized size exceeds maximum ({size} > {MAX_TEMPLATE_STRUCT_SIZE})"
-            )));
-        }
-    }
     if let Some(ref s) = tmpl.driver_config {
         let size = s.encoded_len();
         if size > MAX_TEMPLATE_STRUCT_SIZE {
diff --git a/proto/openshell.proto b/proto/openshell.proto
index bf803e864..d2d884f2e 100644
--- a/proto/openshell.proto
+++ b/proto/openshell.proto
@@ -362,8 +362,8 @@ message SandboxTemplate {
   map<string, string> environment = 6;
   // Platform-specific compute resource requirements and limits.
   google.protobuf.Struct resources = 7;
-  // Optional platform-specific volume claim templates.
-  google.protobuf.Struct volume_claim_templates = 9;
+  reserved 9;
+  reserved "volume_claim_templates";
   // Enable Kubernetes user namespace isolation (hostUsers: false).
   // When true, container UID 0 maps to a non-root host UID and capabilities
   // become namespaced. Requires Kubernetes 1.33+ with user namespace support