diff --git a/src/tools/todo_write.rs b/src/tools/todo_write.rs
index 7267901..e8d893e 100644
--- a/src/tools/todo_write.rs
+++ b/src/tools/todo_write.rs
@@ -297,7 +297,8 @@ impl Tool for TodoWriteTool {
                             continue;
                         }
                     }
-                    if !is_valid_new_status(&new_status) {
+                    // merge 模式：接受任意状态；全量替换模式：必须是 pending 或 in_progress
+                    if !merge_mode && !is_valid_new_status(&new_status) {
                         validation_errors.push(format!(
                             "Item '{}': new items must start as 'pending' or 'in_progress', got '{}'",
                             content, status_str
@@ -339,7 +340,8 @@ impl Tool for TodoWriteTool {
                         continue;
                     }
                 }
-                if !is_valid_new_status(&new_status) {
+                // merge 模式：接受任意状态；全量替换模式：必须是 pending 或 in_progress
+                if !merge_mode && !is_valid_new_status(&new_status) {
                     validation_errors.push(format!(
                         "Item '{}': new items must start as 'pending' or 'in_progress', got '{}'",
                         content, status_str