diff --git a/src/GameCult.Geometry/CultGeometryDocuments.cs b/src/GameCult.Geometry/CultGeometryDocuments.cs
index 0da8af90..5d9ddaa9 100644
--- a/src/GameCult.Geometry/CultGeometryDocuments.cs
+++ b/src/GameCult.Geometry/CultGeometryDocuments.cs
@@ -7,6 +7,10 @@ using GameCult.Caching;
 using MessagePack;
 using static GameCult.Geometry.CultGeometryDocuments;
 
+// The generator emits a resolver for these [MessagePackObject] documents; without this it would try to
+// generate a formatter for the CultRecordRef<T> reference members instead of using the cache's.
+[assembly: MessagePackKnownFormatter(typeof(CultRecordRefFormatter<>))]
+
 namespace GameCult.Geometry
 {
     /// <summary>
diff --git a/src/GameCult.Geometry/GameCult.Geometry.csproj b/src/GameCult.Geometry/GameCult.Geometry.csproj
index c10c2ecf..c1588906 100644
--- a/src/GameCult.Geometry/GameCult.Geometry.csproj
+++ b/src/GameCult.Geometry/GameCult.Geometry.csproj
@@ -10,6 +10,7 @@
   <ItemGroup>
     <ProjectReference Include="..\..\packages\cultmath\src\CultMath\CultMath.csproj" />
     <ProjectReference Include="..\GameCult.Caching\GameCult.Caching.csproj" />
+    <ProjectReference Include="..GameCult.Caching.MessagePackGameCult.Caching.MessagePack.csproj" />
     <PackageReference Include="MessagePack" Version="3.1.7" />
     <PackageReference Include="System.Text.Json" Version="9.0.10" />
   </ItemGroup>