(feat): Add a ToDo tool to track ongoing task lists (#8761)

Co-authored-by: joshualitt <joshualitt@google.com>
Co-authored-by: Tommaso Sciortino <sciortino@gmail.com>
Co-authored-by: matt korwel <matt.korwel@gmail.com>
Co-authored-by: gemini-cli-robot <gemini-cli-robot@google.com>
Co-authored-by: Jacob MacDonald <jakemac@google.com>
Co-authored-by: Shreya Keshive <skeshive@gmail.com>

packages/core/src/config/config.ts

@@ -50,6 +50,7 @@ import {
 import { shouldAttemptBrowserLaunch } from '../utils/browser.js';
 import type { MCPOAuthConfig } from '../mcp/oauth-provider.js';
 import { ideContextStore } from '../ide/ideContext.js';
+import { WriteTodosTool } from '../tools/write-todos.js';
 import type { FileSystemService } from '../services/fileSystemService.js';
 import { StandardFileSystemService } from '../services/fileSystemService.js';
 import {
@@ -245,6 +246,7 @@ export interface ConfigParameters {
   enableToolOutputTruncation?: boolean;
   eventEmitter?: EventEmitter;
   useSmartEdit?: boolean;
+  useWriteTodos?: boolean;
   policyEngineConfig?: PolicyEngineConfig;
   output?: OutputSettings;
   useModelRouter?: boolean;
@@ -332,6 +334,7 @@ export class Config {
   private readonly fileExclusions: FileExclusions;
   private readonly eventEmitter?: EventEmitter;
   private readonly useSmartEdit: boolean;
+  private readonly useWriteTodos: boolean;
   private readonly messageBus: MessageBus;
   private readonly policyEngine: PolicyEngine;
   private readonly outputSettings: OutputSettings;
@@ -421,6 +424,7 @@ export class Config {
     this.enableToolOutputTruncation =
       params.enableToolOutputTruncation ?? false;
     this.useSmartEdit = params.useSmartEdit ?? true;
+    this.useWriteTodos = params.useWriteTodos ?? false;
     this.useModelRouter = params.useModelRouter ?? false;
     this.extensionManagement = params.extensionManagement ?? true;
     this.storage = new Storage(this.targetDir);
@@ -947,6 +951,10 @@ export class Config {
     return this.useSmartEdit;
   }
 
+  getUseWriteTodos(): boolean {
+    return this.useWriteTodos;
+  }
+
   getOutputFormat(): OutputFormat {
     return this.outputSettings?.format
       ? this.outputSettings.format
@@ -1047,6 +1055,9 @@ export class Config {
     registerCoreTool(ShellTool, this);
     registerCoreTool(MemoryTool);
     registerCoreTool(WebSearchTool, this);
+    if (this.getUseWriteTodos()) {
+      registerCoreTool(WriteTodosTool, this);
+    }
 
     await registry.discoverAllTools();
     return registry;