feat(a2ui-playground): persist and reuse the conversation share link

packages/genui/a2ui-playground/src/pages/AIChatPage.tsx

@@ -25,7 +25,10 @@ import type { StaticDemo } from '../demos.js';
 import { useConversation } from '../hooks/useConversation.js';
 import type { ModelChatMessage } from '../hooks/useConversation.js';
 import { useResizablePanels } from '../hooks/useResizablePanels.js';
-import { loadConversation } from '../storage/conversationRepo.js';
+import {
+  loadConversation,
+  saveConversationSharePayload,
+} from '../storage/conversationRepo.js';
 import {
   isSharedConversationDoc,
   serializeConversation,
@@ -2154,8 +2157,25 @@ export function AIChatPage(
           showCopyToast(false);
           return;
         }
-        const doc = serializeConversation(record, protocol.name);
-        const conversationUrl = await publishConversation(doc);
+        // Reuse the link already published for this conversation while it is
+        // unchanged, so repeated shares — including after a page reload — copy
+        // the same link instead of uploading a fresh copy (and minting a new
+        // URL) each time. `meta.updatedAt` bumps on every turn or rename, and a
+        // new turn rewrites the snapshot and drops the cached payload.
+        const cached = record.snapshot?.sharePayload;
+        let conversationUrl: string | undefined;
+        if (cached && cached.updatedAt === record.meta.updatedAt) {
+          conversationUrl = cached.url;
+        }
+        if (!conversationUrl) {
+          const doc = serializeConversation(record, protocol.name);
+          conversationUrl = await publishConversation(doc);
+          await saveConversationSharePayload(
+            id,
+            conversationUrl,
+            record.meta.updatedAt,
+          );
+        }
         const link = buildConversationShareUrl(
           conversationUrl,
           baseUrl,

packages/genui/a2ui-playground/src/storage/conversationRepo.ts

@@ -132,6 +132,27 @@ export async function saveConversationMessages(
   await tx.done;
 }
 
+/**
+ * Persist the durable URL of the published share document on the conversation
+ * snapshot, paired with the `meta.updatedAt` it was generated for. Touches only
+ * the snapshot's share field (not `meta.updatedAt`), so it does not invalidate
+ * itself; a later turn rewrites the snapshot and drops it.
+ */
+export async function saveConversationSharePayload(
+  conversationId: string,
+  url: string,
+  updatedAt: number,
+): Promise<void> {
+  const db = await getDB();
+  const tx = db.transaction('snapshots', 'readwrite');
+  const store = tx.objectStore('snapshots');
+  const snapshot = await store.get(conversationId);
+  if (snapshot) {
+    await store.put({ ...snapshot, sharePayload: { url, updatedAt } });
+  }
+  await tx.done;
+}
+
 export function previewTextFromSharedMessages(
   messages: SharedConversationDoc['messages'],
 ): string {

packages/genui/a2ui-playground/src/storage/types.ts

@@ -41,6 +41,13 @@ export interface DataModelSnapshot {
   previewMessages?: unknown[];
   previewPayloadUrls?: PreviewPayloadUrls;
   updatedAt: number;
+  /**
+   * Durable URL of the most recently published "share whole conversation"
+   * document, paired with the `meta.updatedAt` it was generated for. Lets
+   * repeated shares (including after a page reload) reuse the same link until
+   * the conversation changes.
+   */
+  sharePayload?: { url: string; updatedAt: number };
 }
 
 export interface MetaRecord {