diff --git a/include/ikarus/persistence/project.h b/include/ikarus/persistence/project.h
index acd113a..18a35f5 100644
--- a/include/ikarus/persistence/project.h
+++ b/include/ikarus/persistence/project.h
@@ -124,7 +124,7 @@ IKA_API void ikarus_project_get_blueprints(
 /// \pre \li Must exist.
 /// \param error_out \see errors.h
 /// \return The number of blueprints or undefined if an error occurs.
-IKA_API size_t ikarus_project_get_blueprint_count(IkarusProject * project, IkarusErrorData * error_out);
+IKA_API size_t ikarus_project_get_blueprint_count(IkarusProject const * project, IkarusErrorData * error_out);
 
 /// \brief Finds an entity by a given name.
 /// \param project The project to search.
diff --git a/src/ikarus/persistence/project.cpp b/src/ikarus/persistence/project.cpp
index b7c3e89..9c264f1 100644
--- a/src/ikarus/persistence/project.cpp
+++ b/src/ikarus/persistence/project.cpp
@@ -263,7 +263,7 @@ void ikarus_project_get_entities(
     }
 }
 
-size_t ikarus_project_get_entity_count(IkarusProject * project, IkarusErrorData * error_out) {
+size_t ikarus_project_get_entity_count(IkarusProject const * project, IkarusErrorData * error_out) {
     IKARUS_FAIL_IF_NULL(project, 0);
 
     IKARUS_VTRYRV_OR_FAIL(