DecompilerServer

DecompilerServer is a stdio MCP server for decompiling and analyzing managed .NET assemblies. It works well for general assemblies, Unity Assembly-CSharp.dll workflows, and multi-version browsing such as RimWorld mod porting.

Documentation

• README.md: user-facing overview and quick start
• ARCHITECTURE.md: durable technical reference
• TODO.md: backlog and future work

Highlights

• Load assemblies directly with assemblyPath or use Unity-friendly gameDir loading.
• Keep multiple assemblies loaded at once under aliases such as rw14, rw15, and rw16.
• Use memberId follow-up tools without repeatedly resupplying the alias; routing uses the member ID's MVID.
• Compare aliases structurally with compare_contexts, then drill into types or members with compare_symbols.
• Diff individual method bodies with compare_symbols(..., compareMode: "body").
• Decompiled non-type member source is returned as a member-scoped snippet rather than a whole containing type.

Requirements

• .NET 10 runtime for release assets or built output
• .NET 10 SDK if you want to build from source

Build and Run

git clone https://github.com/pardeike/DecompilerServer.git
cd DecompilerServer
dotnet build DecompilerServer.sln -c Release
dotnet run --project DecompilerServer.csproj -c Release

MCP Client Launch

Framework-dependent build output:

command: dotnet
args:
  - /absolute/path/to/DecompilerServer/bin/Release/net10.0/DecompilerServer.dll

Native app host from dotnet build:

• macOS/Linux: /absolute/path/to/DecompilerServer/bin/Release/net10.0/DecompilerServer
• Windows: C:\\absolute\\path\\to\\DecompilerServer\\bin\\Release\\net10.0\\DecompilerServer.exe

Native app host from dotnet publish:

• macOS/Linux: /absolute/path/to/DecompilerServer/bin/Release/net10.0/publish/DecompilerServer
• Windows: C:\\absolute\\path\\to\\DecompilerServer\\bin\\Release\\net10.0\\publish\\DecompilerServer.exe

Release assets are packaged as framework-dependent single-file executables and still require the .NET 10 runtime.

Basic Workflow

Load one or more assemblies:

load_assembly({
  "assemblyPath": "/path/to/rw14/Assembly-CSharp.dll",
  "contextAlias": "rw14"
})

load_assembly({
  "gameDir": "/path/to/rw16",
  "assemblyFile": "Assembly-CSharp.dll",
  "contextAlias": "rw16"
})

Inspect loaded aliases:

list_contexts({})
status({})

Search and decompile:

search_types({
  "query": "Pawn",
  "limit": 10,
  "contextAlias": "rw16"
})

get_decompiled_source({
  "memberId": "<member-id-from-search>"
})

Once you have a memberId, follow-up tools normally route to the correct loaded assembly automatically.

Compare aliases:

compare_contexts({
  "leftContextAlias": "rw14",
  "rightContextAlias": "rw16",
  "namespaceFilter": "Verse",
  "deep": true
})

compare_symbols({
  "leftContextAlias": "rw14",
  "rightContextAlias": "rw16",
  "symbol": "Verse.Root_Play",
  "symbolKind": "type"
})

compare_symbols({
  "leftContextAlias": "rw14",
  "rightContextAlias": "rw16",
  "symbol": "Verse.Pawn:Kill",
  "symbolKind": "method",
  "compareMode": "body"
})

Development

dotnet format DecompilerServer.sln
dotnet test -c Release --no-restore

Releasing

The GitHub Release workflow is triggered by pushing a tag that starts with v and matches the project version in DecompilerServer.csproj.

For example, if the project version is 1.3.3:

git tag -a v1.3.3 -m "Release v1.3.3"
git push origin v1.3.3

If you are changing implementation details, tool-routing behavior, compare semantics, or test patterns, update ARCHITECTURE.md rather than creating a new standalone guide.