fix(core): prevent duplicate tool schemas for instantiated tools (#22204)

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

@@ -33,6 +33,7 @@ import {
   type PartListUnion,
   type Tool,
   type CallableTool,
+  type FunctionDeclaration,
 } from '@google/genai';
 import type { Config } from '../config/config.js';
 import { MockTool } from '../test-utils/mock-tool.js';
@@ -560,6 +561,34 @@ describe('LocalAgentExecutor', () => {
 
       getToolSpy.mockRestore();
     });
+
+    it('should not duplicate schemas when instantiated tools are provided in toolConfig', async () => {
+      // Create an instantiated mock tool
+      const instantiatedTool = new MockTool({ name: 'instantiated_tool' });
+
+      // Create an agent definition containing the instantiated tool
+      const definition = createTestDefinition([instantiatedTool]);
+
+      // Create the executor
+      const executor = await LocalAgentExecutor.create(
+        definition,
+        mockConfig,
+        onActivity,
+      );
+
+      // Extract the prepared tools list using the private method
+      const toolsList = (
+        executor as unknown as { prepareToolsList: () => FunctionDeclaration[] }
+      ).prepareToolsList();
+
+      // Filter for the specific tool schema
+      const foundSchemas = (
+        toolsList as unknown as FunctionDeclaration[]
+      ).filter((t: FunctionDeclaration) => t.name === 'instantiated_tool');
+
+      // Assert that there is exactly ONE schema for this tool
+      expect(foundSchemas).toHaveLength(1);
+    });
   });
 
   describe('run (Execution Loop and Logic)', () => {

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

@@ -1209,17 +1209,12 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
 
     if (toolConfig) {
       for (const toolRef of toolConfig.tools) {
-        if (typeof toolRef === 'string') {
-          // The names were already expanded and loaded into the registry during creation.
-        } else if (typeof toolRef === 'object' && 'schema' in toolRef) {
-          // Tool instance with an explicit schema property.
-          toolsList.push(toolRef.schema);
-        } else {
+        if (typeof toolRef === 'object' && !('schema' in toolRef)) {
           // Raw `FunctionDeclaration` object.
           toolsList.push(toolRef);
         }
       }
-      // Add schemas from tools that were explicitly registered by name or wildcard.
+      // Add schemas from tools that were explicitly registered by name, wildcard, or instance.
       toolsList.push(...this.toolRegistry.getFunctionDeclarations());
     }