Disallow Object.create() and reflect. (#22408)

packages/core/src/agents/agent-scheduler.ts

@@ -57,18 +57,8 @@ export async function scheduleAgentTools(
   } = options;
 
   // Create a proxy/override of the config to provide the agent-specific tool registry.
-  // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
-  const agentConfig: Config = Object.create(config);
-  agentConfig.getToolRegistry = () => toolRegistry;
-  agentConfig.getMessageBus = () => toolRegistry.messageBus;
-  // Override toolRegistry property so AgentLoopContext reads the agent-specific registry.
-  Object.defineProperty(agentConfig, 'toolRegistry', {
-    get: () => toolRegistry,
-    configurable: true,
-  });
-
   const schedulerContext = {
-    config: agentConfig,
+    config,
     promptId: config.promptId,
     toolRegistry,
     messageBus: toolRegistry.messageBus,

packages/core/src/agents/local-executor.ts

@@ -26,7 +26,6 @@ import {
 } from '../tools/mcp-tool.js';
 import { CompressionStatus } from '../core/turn.js';
 import { type ToolCallRequestInfo } from '../scheduler/types.js';
-import { type Message } from '../confirmation-bus/types.js';
 import { ChatCompressionService } from '../services/chatCompressionService.js';
 import { getDirectoryContextString } from '../utils/environmentContext.js';
 import { promptIdContext } from '../utils/promptIdContext.js';
@@ -128,19 +127,7 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
     const parentMessageBus = context.messageBus;
 
     // Create an override object to inject the subagent name into tool confirmation requests
-    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
-    const subagentMessageBus = Object.create(
-      parentMessageBus,
-    ) as typeof parentMessageBus;
-    subagentMessageBus.publish = async (message: Message) => {
-      if (message.type === 'tool-confirmation-request') {
-        return parentMessageBus.publish({
-          ...message,
-          subagent: definition.name,
-        });
-      }
-      return parentMessageBus.publish(message);
-    };
+    const subagentMessageBus = parentMessageBus.derive(definition.name);
 
     // Create an isolated tool registry for this agent instance.
     const agentToolRegistry = new ToolRegistry(

packages/core/src/agents/registry.ts

@@ -520,23 +520,55 @@ export class AgentRegistry {
       return definition;
     }
 
-    // Use Object.create to preserve lazy getters on the definition object
-    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
-    const merged: LocalAgentDefinition<TOutput> = Object.create(definition);
-
-    if (overrides.runConfig) {
-      merged.runConfig = {
-        ...definition.runConfig,
-        ...overrides.runConfig,
-      };
-    }
-
-    if (overrides.modelConfig) {
-      merged.modelConfig = ModelConfigService.merge(
-        definition.modelConfig,
-        overrides.modelConfig,
-      );
-    }
+    // Preserve lazy getters on the definition object by wrapping in a new object with getters
+    const merged: LocalAgentDefinition<TOutput> = {
+      get kind() {
+        return definition.kind;
+      },
+      get name() {
+        return definition.name;
+      },
+      get displayName() {
+        return definition.displayName;
+      },
+      get description() {
+        return definition.description;
+      },
+      get experimental() {
+        return definition.experimental;
+      },
+      get metadata() {
+        return definition.metadata;
+      },
+      get inputConfig() {
+        return definition.inputConfig;
+      },
+      get outputConfig() {
+        return definition.outputConfig;
+      },
+      get promptConfig() {
+        return definition.promptConfig;
+      },
+      get toolConfig() {
+        return definition.toolConfig;
+      },
+      get processOutput() {
+        return definition.processOutput;
+      },
+      get runConfig() {
+        return overrides.runConfig
+          ? { ...definition.runConfig, ...overrides.runConfig }
+          : definition.runConfig;
+      },
+      get modelConfig() {
+        return overrides.modelConfig
+          ? ModelConfigService.merge(
+              definition.modelConfig,
+              overrides.modelConfig,
+            )
+          : definition.modelConfig;
+      },
+    };
 
     return merged;
   }