feat: Add enableSubagents configuration and wire up subagent registration (#9988)

packages/core/src/config/config.ts

@@ -76,6 +76,9 @@ import type { PolicyEngineConfig } from '../policy/types.js';
 import type { UserTierId } from '../code_assist/types.js';
 import { ProxyAgent, setGlobalDispatcher } from 'undici';
 
+import { AgentRegistry } from '../agents/registry.js';
+import { SubagentToolWrapper } from '../agents/subagent-tool-wrapper.js';
+
 export enum ApprovalMode {
   DEFAULT = 'default',
   AUTO_EDIT = 'autoEdit',
@@ -255,11 +258,13 @@ export interface ConfigParameters {
   output?: OutputSettings;
   useModelRouter?: boolean;
   enableMessageBusIntegration?: boolean;
+  enableSubagents?: boolean;
 }
 
 export class Config {
   private toolRegistry!: ToolRegistry;
   private promptRegistry!: PromptRegistry;
+  private agentRegistry!: AgentRegistry;
   private readonly sessionId: string;
   private fileSystemService: FileSystemService;
   private contentGeneratorConfig!: ContentGeneratorConfig;
@@ -345,6 +350,7 @@ export class Config {
   private readonly outputSettings: OutputSettings;
   private readonly useModelRouter: boolean;
   private readonly enableMessageBusIntegration: boolean;
+  private readonly enableSubagents: boolean;
 
   constructor(params: ConfigParameters) {
     this.sessionId = params.sessionId;
@@ -433,6 +439,7 @@ export class Config {
     this.useModelRouter = params.useModelRouter ?? false;
     this.enableMessageBusIntegration =
       params.enableMessageBusIntegration ?? false;
+    this.enableSubagents = params.enableSubagents ?? false;
     this.extensionManagement = params.extensionManagement ?? true;
     this.storage = new Storage(this.targetDir);
     this.enablePromptCompletion = params.enablePromptCompletion ?? false;
@@ -474,6 +481,10 @@ export class Config {
       await this.getGitService();
     }
     this.promptRegistry = new PromptRegistry();
+
+    this.agentRegistry = new AgentRegistry(this);
+    await this.agentRegistry.initialize();
+
     this.toolRegistry = await this.createToolRegistry();
 
     await this.geminiClient.initialize();
@@ -620,6 +631,10 @@ export class Config {
     return this.workspaceContext;
   }
 
+  getAgentRegistry(): AgentRegistry {
+    return this.agentRegistry;
+  }
+
   getToolRegistry(): ToolRegistry {
     return this.toolRegistry;
   }
@@ -996,6 +1011,10 @@ export class Config {
     return this.enableMessageBusIntegration;
   }
 
+  getEnableSubagents(): boolean {
+    return this.enableSubagents;
+  }
+
   async createToolRegistry(): Promise<ToolRegistry> {
     const registry = new ToolRegistry(this, this.eventEmitter);
 
@@ -1087,6 +1106,41 @@ export class Config {
       registerCoreTool(WriteTodosTool, this);
     }
 
+    // Register Subagents as Tools
+    if (this.getEnableSubagents()) {
+      const agentDefinitions = this.agentRegistry.getAllDefinitions();
+      for (const definition of agentDefinitions) {
+        // We must respect the main allowed/exclude lists for agents too.
+        const excludeTools = this.getExcludeTools() || [];
+        const allowedTools = this.getAllowedTools();
+
+        const isExcluded = excludeTools.includes(definition.name);
+        const isAllowed =
+          !allowedTools || allowedTools.includes(definition.name);
+
+        if (isAllowed && !isExcluded) {
+          try {
+            const messageBusEnabled = this.getEnableMessageBusIntegration();
+            const wrapper = new SubagentToolWrapper(
+              definition,
+              this,
+              messageBusEnabled ? this.getMessageBus() : undefined,
+            );
+            registry.registerTool(wrapper);
+          } catch (error) {
+            console.error(
+              `Failed to wrap agent '${definition.name}' as a tool:`,
+              error,
+            );
+          }
+        } else if (this.getDebugMode()) {
+          console.log(
+            `[Config] Skipping registration of agent '${definition.name}' due to allow/exclude configuration.`,
+          );
+        }
+      }
+    }
+
     await registry.discoverAllTools();
     return registry;
   }