diff --git a/sdk/src/tools/list-directory.ts b/sdk/src/tools/list-directory.ts
index 3bf66fa968..e7a1bd6fca 100644
--- a/sdk/src/tools/list-directory.ts
+++ b/sdk/src/tools/list-directory.ts
@@ -13,6 +13,20 @@ export async function listDirectory(params: {
   try {
     const resolvedPath = path.resolve(projectPath, directoryPath)
 
+    if (
+      !resolvedPath.startsWith(projectPath + path.sep) &&
+      resolvedPath !== projectPath
+    ) {
+      return [
+        {
+          type: 'json',
+          value: {
+            errorMessage: `Invalid path: Path '${directoryPath}' is outside the project directory.`,
+          },
+        },
+      ]
+    }
+
     const entries = await fs.readdir(resolvedPath, {
       withFileTypes: true,
     })