feat(server): code-mode override export and ownership enforcement (#17228)

Co-authored-by: Mastra Code (anthropic/claude-opus-4-7) <noreply@mastra.ai>

Author: DanielSLew

.changeset/editor-code-mode-server.md

@@ -0,0 +1,10 @@
+---
+'@mastra/server': minor
+'@mastra/client-js': minor
+---
+
+Added an agent override export API and server-side ownership enforcement.
+
+The server and client now expose an agent override export endpoint so Studio can download an agent's overrides as JSON for review or commit workflows. Saves are enforced server-side against each agent's `editor` config, so only owned fields (instructions, tools, or tool descriptions) are persisted and fields locked by the `editor` config are stripped.
+
+The system packages response also reports the active editor `source` so clients can render the correct editing experience.

client-sdks/client-js/src/resources/stored-agent.ts

@@ -13,6 +13,8 @@ import type {
   CompareVersionsResponse,
   DeleteAgentVersionResponse,
   FavoriteToggleResponse,
+  ExportStoredAgentParams,
+  ExportStoredAgentResponse,
 } from '../types';
 import { requestContextQueryString } from '../utils';
 
@@ -64,6 +66,16 @@ export class StoredAgent extends BaseResource {
     );
   }
 
+  /**
+   * Exports deterministic JSON for this agent without mutating storage.
+   */
+  export(params: ExportStoredAgentParams): Promise<ExportStoredAgentResponse> {
+    return this.request(`/stored/agents/${encodeURIComponent(this.storedAgentId)}/export`, {
+      method: 'POST',
+      body: params,
+    });
+  }
+
   /**
    * Deletes the stored agent
    * @param requestContext - Optional request context to pass as query parameter