Enable write_todo tool and fix output function schema (#12905)

docs/get-started/configuration.md

@@ -480,8 +480,8 @@ their corresponding top-level category object in your `settings.json` file.
 #### `useWriteTodos`
 
 - **`useWriteTodos`** (boolean):
-  - **Description:** Enable the write_todos_list tool.
-  - **Default:** `false`
+  - **Description:** Enable the write_todos tool.
+  - **Default:** `true`
 
 #### `security`
 

docs/tools/todos.md

@@ -6,7 +6,8 @@ This document describes the `write_todos` tool for the Gemini CLI.
 
 The `write_todos` tool allows the Gemini agent to create and manage a list of
 subtasks for complex user requests. This provides you, the user, with greater
-visibility into the agent's plan and its current progress.
+visibility into the agent's plan and its current progress. It also helps with
+alignment where the agent is less likely to lose track of its current goal.
 
 ### Arguments
 
@@ -49,8 +50,8 @@ write_todos({
 
 ## Important notes
 
-- **Enabling:** This tool is disabled by default. To use it, you must enable it
-  in your `settings.json` file by setting `"useWriteTodos": true`.
+- **Enabling:** This tool is enabled by default. You can disable it in your
+  `settings.json` file by setting `"useWriteTodos": false`.
 
 - **Intended Use:** This tool is primarily used by the agent for complex,
   multi-turn tasks. It is generally not used for simple, single-turn questions.

packages/cli/src/config/settingsSchema.ts

@@ -1080,8 +1080,8 @@ const SETTINGS_SCHEMA = {
     label: 'Use WriteTodos',
     category: 'Advanced',
     requiresRestart: false,
-    default: false,
-    description: 'Enable the write_todos_list tool.',
+    default: true,
+    description: 'Enable the write_todos tool.',
     showInDialog: false,
   },
   security: {

packages/cli/src/ui/components/messages/Todo.test.tsx

@@ -20,7 +20,7 @@ const createTodoHistoryItem = (todos: Todo[]): HistoryItem =>
     id: '1',
     tools: [
       {
-        name: 'write_todos_list',
+        name: 'write_todos',
         callId: 'tool-1',
         status: ToolCallStatus.Success,
         resultDisplay: {

packages/cli/src/ui/hooks/usePhraseCycler.ts

@@ -200,7 +200,7 @@ export const INFORMATIVE_TIPS = [
   'Set the number of lines to keep when truncating outputs (/settings)...',
   'Enable policy-based tool confirmation via message bus (/settings)...',
   'Enable smart-edit tool for more precise editing (/settings)...',
-  'Enable write_todos_list tool to generate task lists (/settings)...',
+  'Enable write_todos tool to generate task lists (/settings)...',
   'Enable model routing based on complexity (/settings)...',
   'Enable experimental subagents for task delegation (/settings)...',
   //Settings tips end here

packages/core/src/config/config.ts

@@ -514,7 +514,7 @@ export class Config {
       params.truncateToolOutputLines ?? DEFAULT_TRUNCATE_TOOL_OUTPUT_LINES;
     this.enableToolOutputTruncation = params.enableToolOutputTruncation ?? true;
     this.useSmartEdit = params.useSmartEdit ?? true;
-    this.useWriteTodos = params.useWriteTodos ?? false;
+    this.useWriteTodos = params.useWriteTodos ?? true;
     this.initialUseModelRouter = params.useModelRouter ?? false;
     this.useModelRouter = this.initialUseModelRouter;
     this.disableModelRouterForAuth = params.disableModelRouterForAuth ?? [];

packages/core/src/tools/write-todos.ts

@@ -173,14 +173,48 @@ export class WriteTodosTool extends BaseDeclarativeTool<
                 },
               },
               required: ['description', 'status'],
+              additionalProperties: false,
             },
           },
         },
         required: ['todos'],
+        additionalProperties: false,
       },
     );
   }
 
+  override get schema() {
+    return {
+      name: this.name,
+      description: this.description,
+      parametersJsonSchema: this.parameterSchema,
+      responseJsonSchema: {
+        type: 'object',
+        properties: {
+          todos: {
+            type: 'array',
+            items: {
+              type: 'object',
+              properties: {
+                description: {
+                  type: 'string',
+                },
+                status: {
+                  type: 'string',
+                  enum: TODO_STATUSES,
+                },
+              },
+              required: ['description', 'status'],
+              additionalProperties: false,
+            },
+          },
+        },
+        required: ['todos'],
+        additionalProperties: false,
+      },
+    };
+  }
+
   protected override validateToolParamValues(
     params: WriteTodosToolParams,
   ): string | null {

schemas/settings.schema.json

@@ -990,9 +990,9 @@
     },
     "useWriteTodos": {
       "title": "Use WriteTodos",
-      "description": "Enable the write_todos_list tool.",
-      "markdownDescription": "Enable the write_todos_list tool.\n\n- Category: `Advanced`\n- Requires restart: `no`\n- Default: `false`",
-      "default": false,
+      "description": "Enable the write_todos tool.",
+      "markdownDescription": "Enable the write_todos tool.\n\n- Category: `Advanced`\n- Requires restart: `no`\n- Default: `true`",
+      "default": true,
       "type": "boolean"
     },
     "security": {