diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 06b9663..24cf50c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,6 @@
 name: CI
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   linux-build-test:
diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
index b39c8c9..96dd2e8 100644
--- a/.github/workflows/clang-format.yml
+++ b/.github/workflows/clang-format.yml
@@ -1,6 +1,6 @@
 name: Test coding style
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
diff --git a/include/snowhouse/stringize.h b/include/snowhouse/stringize.h
index 6b99520..82753bb 100644
--- a/include/snowhouse/stringize.h
+++ b/include/snowhouse/stringize.h
@@ -75,6 +75,15 @@ namespace snowhouse
       }
     };
 
+    template<>
+    struct DefaultStringizer<bool, true>
+    {
+      static std::string ToString(bool value)
+      {
+        return value ? "true" : "false";
+      }
+    };
+
     template<typename T>
     struct DefaultStringizer<T, false>
     {