From 64880636bfea1ef3dcce1bfedd4a7405fb64806c Mon Sep 17 00:00:00 2001
From: Adam Weidman <adamfweidman@google.com>
Date: Tue, 12 May 2026 17:01:28 -0400
Subject: [PATCH] feat(core): add adk.agentSessionSubagentEnabled experimental
 flag

---
 packages/core/src/config/config.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index b81737b0ea..afee865ddd 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -240,6 +240,7 @@ export interface GemmaModelRouterSettings {
 export interface ADKSettings {
   agentSessionNoninteractiveEnabled?: boolean;
   agentSessionInteractiveEnabled?: boolean;
+  agentSessionSubagentEnabled?: boolean;
 }
 
 export interface ExtensionSetting {
@@ -913,6 +914,7 @@ export class Config implements McpContext, AgentLoopContext {
   private readonly gemmaModelRouter: GemmaModelRouterSettings;
   private readonly agentSessionNoninteractiveEnabled: boolean;
   private readonly agentSessionInteractiveEnabled: boolean;
+  private readonly agentSessionSubagentEnabled: boolean;
 
   private readonly retryFetchErrors: boolean;
   private readonly maxAttempts: number;
@@ -1361,6 +1363,8 @@ export class Config implements McpContext, AgentLoopContext {
       params.adk?.agentSessionNoninteractiveEnabled ?? false;
     this.agentSessionInteractiveEnabled =
       params.adk?.agentSessionInteractiveEnabled ?? false;
+    this.agentSessionSubagentEnabled =
+      params.adk?.agentSessionSubagentEnabled ?? false;
     this.retryFetchErrors = params.retryFetchErrors ?? true;
     this.maxAttempts = Math.min(
       params.maxAttempts ?? DEFAULT_MAX_ATTEMPTS,
@@ -2553,6 +2557,10 @@ export class Config implements McpContext, AgentLoopContext {
     return this.contextManagement.enabled;
   }
 
+  isAgentSessionEnabled(): boolean {
+    return this.agentSessionSubagentEnabled;
+  }
+
   getMemoryBoundaryMarkers(): readonly string[] {
     return this.memoryBoundaryMarkers;
   }