diff --git a/.changeset/seven-numbers-juggle.md b/.changeset/seven-numbers-juggle.md
new file mode 100644
index 00000000..af6b8e14
--- /dev/null
+++ b/.changeset/seven-numbers-juggle.md
@@ -0,0 +1,5 @@
+---
+"task-master-ai": patch
+---
+
+Fix addTask tool `projectRoot not defined`
diff --git a/mcp-server/src/tools/addTask.js b/mcp-server/src/tools/addTask.js
index 0b12d9fc..4d0cdade 100644
--- a/mcp-server/src/tools/addTask.js
+++ b/mcp-server/src/tools/addTask.js
@@ -45,6 +45,8 @@ export function registerAddTaskTool(server) {
         if (args.priority) cmdArgs.push(`--priority=${args.priority}`);
         if (args.file) cmdArgs.push(`--file=${args.file}`);
 
+        const projectRoot = args.projectRoot;
+
         const result = executeTaskMasterCommand(
           "add-task",
           log,