trying to make it work

public/app/features/annotations/api.ts

@@ -1,7 +1,11 @@
 import { AnnotationEvent, DataFrame, toDataFrame } from '@grafana/data';
-import { getBackendSrv } from '@grafana/runtime';
+import { config, getBackendSrv } from '@grafana/runtime';
 import { StateHistoryItem } from 'app/types/unified-alerting';
 
+import { getAPINamespace } from '../../api/utils';
+import { ScopedResourceClient } from '../apiserver/client';
+import type { Resource, ResourceForCreate, ListOptions } from '../apiserver/types';
+
 import { AnnotationTagsResponse } from './types';
 
 export interface AnnotationServer {
@@ -47,11 +51,182 @@ class LegacyAnnotationServer implements AnnotationServer {
   }
 }
 
+// K8s-style annotation spec based on the CUE definition
+interface K8sAnnotationSpec {
+  text: string;
+  time: number;
+  timeEnd?: number;
+  dashboardUID?: string;
+  panelID?: number;
+  tags?: string[];
+}
+
+interface K8sAnnotationTagsResponse {
+  tags: Array<{ tag: string; count: number }>;
+}
+
+const K8S_ANNOTATION_API_CONFIG = {
+  group: 'annotation.grafana.app',
+  version: 'v0alpha1',
+  resource: 'annotations',
+};
+
+class K8sAnnotationServer implements AnnotationServer {
+  private client: ScopedResourceClient<K8sAnnotationSpec>;
+
+  constructor() {
+    this.client = new ScopedResourceClient<K8sAnnotationSpec>(K8S_ANNOTATION_API_CONFIG);
+  }
+
+  async query(params: Record<string, unknown>, requestId: string): Promise<DataFrame> {
+    // Convert legacy query params to k8s list options
+    const listOpts: ListOptions = {};
+
+    // Map limit parameter
+    if (params.limit) {
+      listOpts.limit = Number(params.limit);
+    }
+
+    // Build field selectors for dashboard/panel filtering and time ranges
+    const fieldSelectors: string[] = [];
+
+    if (params.dashboardUID) {
+      fieldSelectors.push(`spec.dashboardUID=${params.dashboardUID}`);
+    }
+
+    if (params.panelId) {
+      fieldSelectors.push(`spec.panelID=${params.panelId}`);
+    }
+
+    // Handle time range filters using spec.time field  
+    // Note: < and > operators need URL encoding when passed as query parameters
+    // < becomes %3C and > becomes %3E
+    if (params.from) {
+      // Use URL-encoded > operator
+      fieldSelectors.push(`spec.time%3E${params.from}`);
+    }
+
+    if (params.to) {
+      // Use URL-encoded < operator
+      fieldSelectors.push(`spec.time%3C${params.to}`);
+    }
+
+    if (fieldSelectors.length > 0) {
+      listOpts.fieldSelector = fieldSelectors.join(',');
+    }
+
+    // Handle tags using label selectors
+    if (params.tags && Array.isArray(params.tags) && params.tags.length > 0) {
+      // Tags should be converted to label selectors
+      // Format: tag1,tag2 means annotations that have both tags
+      listOpts.labelSelector = params.tags.map((tag) => `tag=${tag}`).join(',');
+    }
+
+    const result = await this.client.list(listOpts);
+
+    // Convert k8s resources to legacy annotation format
+    const annotations = result.items.map((item: Resource<K8sAnnotationSpec>) => ({
+      id: item.metadata.name,
+      ...item.spec,
+      panelId: item.spec.panelID, // Map panelID back to panelId
+    }));
+
+    return toDataFrame(annotations);
+  }
+
+  async forAlert(alertUID: string): Promise<StateHistoryItem[]> {
+    const result = await this.client.list({
+      labelSelector: `alertUID=${alertUID}`,
+    });
+
+    // Return as any[] since the k8s annotation format doesn't match StateHistoryItem exactly
+    // This is a limitation of the current type definitions
+    return result.items.map((item: Resource<K8sAnnotationSpec>) => ({
+      id: item.metadata.name,
+      ...item.spec,
+      panelId: item.spec.panelID,
+    })) as any;
+  }
+
+  async save(annotation: AnnotationEvent): Promise<AnnotationEvent> {
+    const resource: ResourceForCreate<K8sAnnotationSpec> = {
+      metadata: {
+        name: '', // Will be auto-generated by the server
+      },
+      spec: {
+        text: annotation.text || '',
+        time: annotation.time || Date.now(),
+        timeEnd: annotation.timeEnd,
+        dashboardUID: annotation.dashboardUID ?? undefined,
+        panelID: annotation.panelId,
+        tags: annotation.tags,
+      },
+    };
+
+    const result = await this.client.create(resource);
+
+    return {
+      ...annotation,
+      id: result.metadata.name,
+      ...result.spec,
+      panelId: result.spec.panelID,
+    };
+  }
+
+  async update(annotation: AnnotationEvent): Promise<unknown> {
+    if (!annotation.id) {
+      throw new Error('Annotation ID is required for update');
+    }
+
+    // Get the existing resource to preserve metadata
+    const existing = await this.client.get(String(annotation.id));
+
+    // Update only the spec fields
+    const updated: Resource<K8sAnnotationSpec> = {
+      ...existing,
+      spec: {
+        text: annotation.text || existing.spec.text,
+        time: annotation.time || existing.spec.time,
+        timeEnd: annotation.timeEnd ?? existing.spec.timeEnd,
+        dashboardUID: annotation.dashboardUID ? annotation.dashboardUID : existing.spec.dashboardUID,
+        panelID: annotation.panelId ?? existing.spec.panelID,
+        tags: annotation.tags ?? existing.spec.tags,
+      },
+    };
+
+    return this.client.update(updated);
+  }
+
+  async delete(annotation: AnnotationEvent): Promise<unknown> {
+    if (!annotation.id) {
+      throw new Error('Annotation ID is required for delete');
+    }
+    return this.client.delete(String(annotation.id), false);
+  }
+
+  async tags(): Promise<Array<{ term: string; count: number }>> {
+    // Use the custom /tags route defined in the CUE manifest
+    const namespace = getAPINamespace();
+    const url = `/apis/${K8S_ANNOTATION_API_CONFIG.group}/${K8S_ANNOTATION_API_CONFIG.version}/namespaces/${namespace}/${K8S_ANNOTATION_API_CONFIG.resource}/tags`;
+
+    const response = await getBackendSrv().get<K8sAnnotationTagsResponse>(url, { limit: 1000 });
+
+    return response.tags.map(({ tag, count }) => ({
+      term: tag,
+      count,
+    }));
+  }
+}
+
 let instance: AnnotationServer | null = null;
 
 export function annotationServer(): AnnotationServer {
   if (!instance) {
-    instance = new LegacyAnnotationServer();
+    if (config.featureToggles.kubernetesAnnotations) {
+      instance = new K8sAnnotationServer();
+    } else {
+      instance = new LegacyAnnotationServer();
+    }
   }
   return instance;
 }