Resolving external types from Jenny (untested)

Jenny.csproj

<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <Configuration>Jenny</Configuration>
    <Platform>Any CPU</Platform>
    <OutputPath>.\bin\Jenny</OutputPath>
  </PropertyGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.Csharp.targets"/>
  <ItemGroup>
    <Reference Include="Entitas">
      <HintPath>.\Jenny\Plugins\Entitas.Roslyn\Entitas.dll</HintPath>
    </Reference>
    <Reference Include="Entitas.CodeGeneration.Attributes">
      <HintPath>.\Jenny\Plugins\Entitas.Roslyn\Entitas.CodeGeneration.Attributes.dll</HintPath>
    </Reference>
    <Reference Include="MyOtherProject">
      <HintPath>.\bin\Debug\MyOtherProject.dll</HintPath>
    </Reference>
    <Compile Include=".\Source\MyProject\**\*.cs"/>
  </ItemGroup>
</Project>

Jenny.properties

DesperateDevs.CodeGeneration.Plugins.ProjectPath = Jenny.csproj
DesperateDevs.CodeGeneration.Plugins.TargetDirectory = .\Source\MyProject