diff --git a/internal/tools/branch_list.go b/internal/tools/branch_list.go
index 89adb94..f991d75 100644
--- a/internal/tools/branch_list.go
+++ b/internal/tools/branch_list.go
@@ -27,8 +27,8 @@ func (t *BranchList) Descriptor() registry.ToolDescriptor {
 			"properties":{
 				"owner":{"type":"string"},
 				"name":{"type":"string"},
-				"page":{"type":"integer"},
-				"limit":{"type":"integer"}
+				"page":{"type":"integer","minimum":1},
+				"limit":{"type":"integer","minimum":1,"maximum":50}
 			},
 			"required":["owner","name"]
 		}`),