Missing Microsoft.CodeAnalysis.CSharp.Workspaces.dll causes CS0234 Formatting namespace error in Unity 6

Author: SamueleGuerriniCreated Sep 8, 2026Updated Sep 8, 2026

Description

When using MCP for Unity v10.0.0 in a Unity 6 (6000.6) project, the ManageScript.cs file fails to compile with:

Library/PackageCache/com.coplaydev.unity-mcp@045e809812a8/Editor/Tools/ManageScript.cs(17,30): error CS0234: The type or namespace name 'Formatting' does not exist in the namespace 'Microsoft.CodeAnalysis' (are you missing an assembly reference?)

Root Cause

ManageScript.cs conditionally includes Microsoft.CodeAnalysis.Formatting under #if USE_ROSLYN:

csharp

#if USE_ROSLYN
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Formatting;
#endif

The MCPForUnity.Editor.asmdef references:

Microsoft.CodeAnalysis.dll
Microsoft.CodeAnalysis.CSharp.dll

But the Formatting namespace lives in Microsoft.CodeAnalysis.CSharp.Workspaces.dll, which is not referenced in the assembly definition.

Fix

Add Microsoft.CodeAnalysis.CSharp.Workspaces.dll to the precompiledReferences in MCPForUnity.Editor.asmdef:

json

"precompiledReferences": [
    "Newtonsoft.Json.dll",
    "Microsoft.CodeAnalysis.dll",
    "Microsoft.CodeAnalysis.CSharp.dll",
    "Microsoft.CodeAnalysis.CSharp.Workspaces.dll",
    "System.Collections.Immutable.dll",
    "System.Reflection.Metadata.dll",
    "System.Runtime.CompilerServices.Unsafe.dll"
]

Environment

Unity: 6000.6
MCP for Unity: v10.0.0
OS: Windows 11
Branch: main

Source: CoplayDev/unity-mcp

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