Fix: Update system instruction when GEMINI.md memory is loaded or refreshed (#12136)

packages/core/src/config/config.ts

@@ -1020,6 +1020,17 @@ export class Config {
     return this.geminiClient;
   }
 
+  /**
+   * Updates the system instruction with the latest user memory.
+   * Whenever the user memory (GEMINI.md files) is updated.
+   */
+  async updateSystemInstructionIfInitialized(): Promise<void> {
+    const geminiClient = this.getGeminiClient();
+    if (geminiClient?.isInitialized()) {
+      await geminiClient.updateSystemInstruction();
+    }
+  }
+
   getModelRouterService(): ModelRouterService {
     return this.modelRouterService;
   }

packages/core/src/core/client.ts

@@ -168,6 +168,16 @@ export class GeminiClient {
     });
   }
 
+  async updateSystemInstruction(): Promise<void> {
+    if (!this.isInitialized()) {
+      return;
+    }
+
+    const userMemory = this.config.getUserMemory();
+    const systemInstruction = getCoreSystemPrompt(this.config, userMemory);
+    this.getChat().setSystemInstruction(systemInstruction);
+  }
+
   async startChat(
     extraHistory?: Content[],
     resumedSessionData?: ResumedSessionData,