diff --git a/pyproject.toml b/pyproject.toml
index 4e0f270..094b784 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,7 +23,7 @@ classifiers = [
 ]
 dependencies = [
   "icalendar>=7",
-  "mcp[cli]>=1.20",
+  "mcp[cli]>=1.20,<2",
   "niquests>=3",
 ]
 optional-dependencies.dev = [