diff --git a/engine/include/cubos/engine/collisions/broad_phase/candidates.hpp b/engine/include/cubos/engine/collisions/broad_phase/candidates.hpp
index 84cb56ec1a..78c4a61e55 100644
--- a/engine/include/cubos/engine/collisions/broad_phase/candidates.hpp
+++ b/engine/include/cubos/engine/collisions/broad_phase/candidates.hpp
@@ -2,6 +2,8 @@
 /// @brief Resource @ref cubos::engine::Candidates.
 /// @ingroup broad-phase-collisions-plugin
 
+// FIXME: This should be private, but it's used in the sample.
+
 #pragma once
 
 #include <unordered_map>
diff --git a/engine/src/cubos/engine/collisions/broad_phase/plugin.cpp b/engine/src/cubos/engine/collisions/broad_phase/plugin.cpp
index 21142c10b1..57395ee28e 100644
--- a/engine/src/cubos/engine/collisions/broad_phase/plugin.cpp
+++ b/engine/src/cubos/engine/collisions/broad_phase/plugin.cpp
@@ -1,11 +1,14 @@
+
+#include "plugin.hpp"
+
 #include <cubos/engine/collisions/broad_phase/candidates.hpp>
-#include <cubos/engine/collisions/broad_phase/plugin.hpp>
-#include <cubos/engine/collisions/broad_phase/sweep_and_prune.hpp>
 #include <cubos/engine/collisions/collider.hpp>
 #include <cubos/engine/collisions/shapes/box.hpp>
 #include <cubos/engine/collisions/shapes/capsule.hpp>
 #include <cubos/engine/transform/local_to_world.hpp>
 
+#include "sweep_and_prune.hpp"
+
 using cubos::core::ecs::OptRead;
 using cubos::core::ecs::Query;
 using cubos::core::ecs::Read;
diff --git a/engine/include/cubos/engine/collisions/broad_phase/plugin.hpp b/engine/src/cubos/engine/collisions/broad_phase/plugin.hpp
similarity index 100%
rename from engine/include/cubos/engine/collisions/broad_phase/plugin.hpp
rename to engine/src/cubos/engine/collisions/broad_phase/plugin.hpp
diff --git a/engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.cpp b/engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.cpp
index d4170bfe0b..bee8403b02 100644
--- a/engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.cpp
+++ b/engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.cpp
@@ -1,6 +1,6 @@
 #include <algorithm>
 
-#include <cubos/engine/collisions/broad_phase/sweep_and_prune.hpp>
+#include "sweep_and_prune.hpp"
 
 using cubos::core::ecs::Entity;
 using namespace cubos::engine;
diff --git a/engine/include/cubos/engine/collisions/broad_phase/sweep_and_prune.hpp b/engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.hpp
similarity index 100%
rename from engine/include/cubos/engine/collisions/broad_phase/sweep_and_prune.hpp
rename to engine/src/cubos/engine/collisions/broad_phase/sweep_and_prune.hpp
diff --git a/engine/src/cubos/engine/collisions/plugin.cpp b/engine/src/cubos/engine/collisions/plugin.cpp
index 01ab13424d..9be0a37aa9 100644
--- a/engine/src/cubos/engine/collisions/plugin.cpp
+++ b/engine/src/cubos/engine/collisions/plugin.cpp
@@ -1,6 +1,7 @@
+#include "broad_phase/plugin.hpp"
+
 #include <cubos/core/ecs/system/query.hpp>
 
-#include <cubos/engine/collisions/broad_phase/plugin.hpp>
 #include <cubos/engine/collisions/collider.hpp>
 #include <cubos/engine/collisions/plugin.hpp>
 #include <cubos/engine/collisions/shapes/box.hpp>