Library\PackageCache\com.coplaydev.unity-mcp@0c7945b36a\Editor\Tools\ManageScript.cs(16,30): error CS0234: The type or namespace name 'Formatting' does not exist in the namespace 'Microsoft.CodeAnalysis' (are you missing an assembly reference?)

[MisfitCode]

Upon Installing and setting up Roslyn, as per Read Me, user gets the following Error:

Library\PackageCache\com.coplaydev.unity-mcp@0c7945b\Editor\Tools\ManageScript.cs(16,30): error CS0234: The type or namespace name 'Formatting' does not exist in the namespace 'Microsoft.CodeAnalysis' (are you missing an assembly reference?)

Unity 2022.X LTS (newest)
Windows 11 (fully updated)
Clean Unity Build.

[MisfitCode]

After doing some research, and talking to AI, Claude AI suggested it could be that newer versions (4x) of Roslyn could be having unknown Interactions with Unity. I installed Microsoft.CodeAnalysis.CSharp 3.11.0 and the error went away and Unity MCP now loads properly. I did not test every 4x version, I just skipped to the newest 3X version.

[arvz]

I installed Microsoft.CodeAnalysis.CSharp 3.11.0, put in the USE_ROSLYN scripting define symbol, restarted unity, but after adding the UnityMcpBridge package I'm still getting this namespace name 'Formatting' does not exist in the namespace 'Microsoft.CodeAnalysis' issue

[tdcox]

I see the same issue using 3.11.0 and 4.x in Unity 6.2

[msanatan]

Interesting @tdcox. @Scriptwonder I believe you set this up right? I'll have a look if you can't get to it sooner

[Scriptwonder]

Will look into this one! Wonder if it has something to do with the latest merge, will check it out today.

[Scriptwonder]

@dsarno Which version of Roslyn did you test the PR#243 with? I find the compilation errors all involve the change on that PR, the Formatting namespace issue, and the compilation errors once the formatting issues are solved.

I will push a PR later that does not change the manageScript.cs, but only edits the prerequisites of NuGet packages and versions in the Readme instructions, so it will work on Microsoft.CodeAnalysis at 4X; However, for 3.11.0, there is one error I get that shows on line 1519:

"Library\PackageCache\com.coplaydev.unity-mcp@194854625813
  \Editor\Tools\ManageScript.cs(1519,88): error CS0234: The type or 
  namespace name 'FileScopedNamespaceDeclarationSyntax' does not 
  exist in the namespace 'Microsoft.CodeAnalysis.CSharp.Syntax' (are
   you missing an assembly reference?)"

Would be great if you can look into it, thanks! We can close this after this issue is investigated and solved.

[dsarno]

@Scriptwonder I spent a little time on this, but I think we have deeper issues with using Roslyn in ManageScript.cs. For example, right now the strict Rosyln validation in ManageScript doesn't catch:

public void Bad(){ UndefinedSymbol y = 0; Debug.Log(y); }
}

It lets it go as valid. I'm not a Rosyln expert. but it seems we may need more support scaffolding for it to work. GPT5 says:

Build a CSharpCompilation from the parsed SyntaxTree and add references from Unity (e.g., via UnityEditor.Compilation.CompilationPipeline or loaded AppDomain assemblies), then return compilation.GetDiagnostics(). That will report CS0246 and similar.

I wonder if this is a bigger feature effort, and what we need is both (a) a good way to get @justinpbarnett 's installer wizard to install Rosyln on request, and (b) a testing framework to make sure it plays well with our code editing tools (mainly ManageScript.cs).

What do you think?