diff --git a/OpenNest.IO.Tests/IoDependencyTests.cs b/OpenNest.IO.Tests/IoDependencyTests.cs
new file mode 100644
index 00000000..58668cc5
--- /dev/null
+++ b/OpenNest.IO.Tests/IoDependencyTests.cs
@@ -0,0 +1,12 @@
+namespace OpenNest.IO.Tests;
+
+public class IoDependencyTests
+{
+    [Fact]
+    public void IoAssembly_DoesNotReferenceTheEngine()
+    {
+        var references = typeof(NestReader).Assembly.GetReferencedAssemblies().Select(a => a.Name);
+
+        Assert.DoesNotContain("OpenNest.Engine", references);
+    }
+}
diff --git a/OpenNest.IO.Tests/OpenNest.IO.Tests.csproj b/OpenNest.IO.Tests/OpenNest.IO.Tests.csproj
index 4d96dc06..5806137b 100644
--- a/OpenNest.IO.Tests/OpenNest.IO.Tests.csproj
+++ b/OpenNest.IO.Tests/OpenNest.IO.Tests.csproj
@@ -12,5 +12,7 @@
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
     <Using Include="Xunit" />
     <ProjectReference Include="../OpenNest.IO/OpenNest.IO.csproj" />
+    <!-- Some round-trip tests drive whole jobs; OpenNest.IO itself must not reference the engine. -->
+    <ProjectReference Include="../OpenNest.Engine/OpenNest.Engine.csproj" />
   </ItemGroup>
 </Project>
diff --git a/OpenNest.IO/OpenNest.IO.csproj b/OpenNest.IO/OpenNest.IO.csproj
index f6782ef5..e49adae9 100644
--- a/OpenNest.IO/OpenNest.IO.csproj
+++ b/OpenNest.IO/OpenNest.IO.csproj
@@ -9,7 +9,6 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenNest.Core\OpenNest.Core.csproj" />
-    <ProjectReference Include="..\OpenNest.Engine\OpenNest.Engine.csproj" />
     <PackageReference Include="ACadSharp" Version="3.1.32" />
     <PackageReference Include="ClosedXML" Version="0.104.2" />
   </ItemGroup>