diff --git a/src/util.ts b/src/util.ts
index e502e600d9..fe6a0a3558 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -165,6 +165,45 @@ export function normalizeResponseHeaders(response: Response): { [key: string]: s
     return normalizedHeaders;
 }
 
+/**
+ * Built-in Kubernetes API groups that have generated TypeScript models.
+ * Custom resources and third-party API groups (like Knative) are not included.
+ */
+const BUILT_IN_API_GROUPS = new Set([
+    'core', // maps to "" (empty string) for core resources like Pod, Service, etc.
+    'admissionregistration.k8s.io',
+    'apiextensions.k8s.io',
+    'apiregistration.k8s.io',
+    'apps',
+    'authentication.k8s.io',
+    'authorization.k8s.io',
+    'autoscaling',
+    'batch',
+    'certificates.k8s.io',
+    'coordination.k8s.io',
+    'discovery.k8s.io',
+    'events.k8s.io',
+    'flowcontrol.apiserver.k8s.io',
+    'internal.apiserver.k8s.io',
+    'networking.k8s.io',
+    'node.k8s.io',
+    'policy',
+    'rbac.authorization.k8s.io',
+    'resource.k8s.io',
+    'scheduling.k8s.io',
+    'storage.k8s.io',
+    'storagemigration.k8s.io',
+]);
+
+/**
+ * Check if the given API group is a built-in Kubernetes API group.
+ * @param group - The API group to check (e.g., "apps", "serving.knative.dev", "core")
+ * @returns true if the group is a built-in Kubernetes API group, false otherwise
+ */
+function isBuiltInApiGroup(group: string): boolean {
+    return BUILT_IN_API_GROUPS.has(group);
+}
+
 export function getSerializationType(apiVersion?: string, kind?: string): string {
     if (apiVersion === undefined || kind === undefined) {
         return 'KubernetesObject';
@@ -172,6 +211,12 @@ export function getSerializationType(apiVersion?: string, kind?: string): string
     // Types are defined in src/gen/api/models with the format "<Version><Kind>".
     // Version and Kind are in PascalCase.
     const gv = groupVersion(apiVersion);
+
+    // Only return a type name if this is a built-in Kubernetes API group
+    if (!isBuiltInApiGroup(gv.group)) {
+        return 'KubernetesObject';
+    }
+
     const version = gv.version.charAt(0).toUpperCase() + gv.version.slice(1);
     return `${version}${kind}`;
 }
diff --git a/src/util_test.ts b/src/util_test.ts
index 74a323a866..a932b7bbd0 100644
--- a/src/util_test.ts
+++ b/src/util_test.ts
@@ -147,6 +147,18 @@ describe('Utils', () => {
     it('should get the serialization type correctly', () => {
         strictEqual(getSerializationType('v1', 'Pod'), 'V1Pod');
         strictEqual(getSerializationType('apps/v1', 'Deployment'), 'V1Deployment');
+        // Built-in Kubernetes resources should return a type
+        strictEqual(getSerializationType('v1', 'Pod'), 'V1Pod');
+        strictEqual(getSerializationType('apps/v1', 'Deployment'), 'V1Deployment');
+        strictEqual(getSerializationType('v1', 'Service'), 'V1Service');
+        strictEqual(getSerializationType('batch/v1', 'Job'), 'V1Job');
+
+        // Non-built-in resources should return 'KubernetesObject'
+        strictEqual(getSerializationType('serving.knative.dev/v1', 'Service'), 'KubernetesObject');
+        strictEqual(getSerializationType('example.com/v1', 'MyCustomResource'), 'KubernetesObject');
+        strictEqual(getSerializationType('custom.io/v1alpha1', 'CustomThing'), 'KubernetesObject');
+
+        // Undefined inputs should return 'KubernetesObject'
         strictEqual(getSerializationType(undefined, undefined), 'KubernetesObject');
     });
 });
diff --git a/src/yaml_test.ts b/src/yaml_test.ts
index 958f7ba45b..0174393a94 100644
--- a/src/yaml_test.ts
+++ b/src/yaml_test.ts
@@ -2,6 +2,7 @@ import { describe, it } from 'node:test';
 import { deepEqual, deepStrictEqual, strictEqual } from 'node:assert';
 import { V1CustomResourceDefinition, V1Namespace } from './api.js';
 import { dumpYaml, loadAllYaml, loadYaml } from './yaml.js';
+import { KubernetesObject } from './types.js';
 
 describe('yaml', () => {
     it('should load safely', () => {
@@ -154,4 +155,54 @@ spec:
         // not using strict equality as types are not matching
         deepEqual(actual, expected);
     });
+
+    it('should load Knative Service correctly preserving spec', () => {
+        const yaml = `apiVersion: serving.knative.dev/v1
+kind: Service
+metadata:
+  name: hello-world
+spec:
+  template:
+    spec:
+      containers:
+        - image: ghcr.io/knative/helloworld-go:latest
+          ports:
+            - containerPort: 8080
+          env:
+            - name: TARGET
+              value: "World"`;
+        const knativeService = loadYaml(yaml) as KubernetesObject;
+
+        strictEqual(knativeService.apiVersion, 'serving.knative.dev/v1');
+        strictEqual(knativeService.kind, 'Service');
+        strictEqual((knativeService as any).metadata.name, 'hello-world');
+        // Verify that the spec is preserved
+        strictEqual(
+            (knativeService as any).spec.template.spec.containers[0].image,
+            'ghcr.io/knative/helloworld-go:latest',
+        );
+        strictEqual((knativeService as any).spec.template.spec.containers[0].ports[0].containerPort, 8080);
+        strictEqual((knativeService as any).spec.template.spec.containers[0].env[0].name, 'TARGET');
+        strictEqual((knativeService as any).spec.template.spec.containers[0].env[0].value, 'World');
+    });
+
+    it('should load custom resources correctly', () => {
+        const yaml = `apiVersion: example.com/v1
+kind: MyCustomResource
+metadata:
+  name: my-resource
+spec:
+  customField: customValue
+  nestedObject:
+    key1: value1
+    key2: value2`;
+        const customResource = loadYaml(yaml) as KubernetesObject;
+
+        strictEqual((customResource as any).apiVersion, 'example.com/v1');
+        strictEqual((customResource as any).kind, 'MyCustomResource');
+        strictEqual((customResource as any).metadata.name, 'my-resource');
+        strictEqual((customResource as any).spec.customField, 'customValue');
+        strictEqual((customResource as any).spec.nestedObject.key1, 'value1');
+        strictEqual((customResource as any).spec.nestedObject.key2, 'value2');
+    });
 });