fix: 新创建 todo 项允许直接设为 in_progress，无需先 pending 再更新

agent 创建 todo 列表时可以将第一个任务直接标为 in_progress，
避免浪费一次工具调用。仍然禁止新项为 completed/cancelled。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/tools/todo_write.rs

@@ -273,9 +273,9 @@ impl Tool for TodoWriteTool {
                     });
                 } else {
                     // 传入 id 但旧状态中没有 → 按新 item 处理
-                    if new_status != TodoStatus::Pending {
+                    if !is_valid_new_status(&new_status) {
                         validation_errors.push(format!(
-                            "Item '{}': new items must start as 'pending', got '{}'",
+                            "Item '{}': new items must start as 'pending' or 'in_progress', got '{}'",
                             content, status_str
                         ));
                         continue;
@@ -291,10 +291,10 @@ impl Tool for TodoWriteTool {
                     });
                 }
             } else {
-                // 新 item（无 id）— 必须是 pending
-                if new_status != TodoStatus::Pending {
+                // 新 item（无 id）— 允许 pending 或 in_progress
+                if !is_valid_new_status(&new_status) {
                     validation_errors.push(format!(
-                        "Item '{}': new items must start as 'pending', got '{}'",
+                        "Item '{}': new items must start as 'pending' or 'in_progress', got '{}'",
                         content, status_str
                     ));
                     continue;
@@ -423,6 +423,11 @@ pub(crate) fn scope_key_from_context(context: &ToolContext) -> Option<String> {
     tid.or(sid).map(str::to_string)
 }
 
+/// 新创建的 item 允许 pending 或 in_progress，不允许 completed/cancelled
+fn is_valid_new_status(status: &TodoStatus) -> bool {
+    matches!(status, TodoStatus::Pending | TodoStatus::InProgress)
+}
+
 /// 校验状态转换合法性
 fn validate_transition(old: &TodoStatus, new: &TodoStatus) -> Result<(), String> {
     if old.is_terminal() {
@@ -694,7 +699,7 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn test_new_item_must_be_pending() {
+    async fn test_new_item_cannot_be_completed_or_cancelled() {
         let tool = TodoWriteTool::new(test_state());
         let context = test_context();
 
@@ -711,7 +716,49 @@ mod tests {
             .unwrap();
 
         assert!(!result.success);
-        assert!(result.error.unwrap().contains("must start as 'pending'"));
+        assert!(result.error.unwrap().contains("new items must start as"));
+
+        let result2 = tool
+            .execute_with_context(
+                &context,
+                json!({
+                    "todos": [
+                        {"content": "任务B", "status": "cancelled"}
+                    ]
+                }),
+            )
+            .await
+            .unwrap();
+
+        assert!(!result2.success);
+        assert!(result2.error.unwrap().contains("new items must start as"));
+    }
+
+    #[tokio::test]
+    async fn test_new_item_can_start_as_in_progress() {
+        let tool = TodoWriteTool::new(test_state());
+        let context = test_context();
+
+        // 直接创建第一个任务为 in_progress — 应该允许
+        let result = tool
+            .execute_with_context(
+                &context,
+                json!({
+                    "todos": [
+                        {"content": "第一个任务", "status": "in_progress"},
+                        {"content": "第二个任务", "status": "pending"},
+                        {"content": "第三个任务", "status": "pending"}
+                    ]
+                }),
+            )
+            .await
+            .unwrap();
+
+        assert!(result.success);
+        let output: serde_json::Value = serde_json::from_str(&result.output).unwrap();
+        let todos = output["current_todos"].as_array().unwrap();
+        assert_eq!(todos.len(), 3);
+        assert_eq!(todos[0]["status"], "in_progress");
     }
 
     #[tokio::test]