Improve Function Call argument validation and typing (#2881)

Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>

packages/core/src/tools/memoryTool.ts

@@ -5,19 +5,20 @@
  */
 
 import { BaseTool, ToolResult } from './tools.js';
+import { FunctionDeclaration, Type } from '@google/genai';
 import * as fs from 'fs/promises';
 import * as path from 'path';
 import { homedir } from 'os';
 
-const memoryToolSchemaData = {
+const memoryToolSchemaData: FunctionDeclaration = {
   name: 'save_memory',
   description:
     'Saves a specific piece of information or fact to your long-term memory. Use this when the user explicitly asks you to remember something, or when they state a clear, concise fact that seems important to retain for future interactions.',
   parameters: {
-    type: 'object',
+    type: Type.OBJECT,
     properties: {
       fact: {
-        type: 'string',
+        type: Type.STRING,
         description:
           'The specific fact or piece of information to remember. Should be a clear, self-contained statement.',
       },
@@ -98,7 +99,7 @@ function ensureNewlineSeparation(currentContent: string): string {
 }
 
 export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
-  static readonly Name: string = memoryToolSchemaData.name;
+  static readonly Name: string = memoryToolSchemaData.name!;
   constructor() {
     super(
       MemoryTool.Name,