ILSpy MCP Server

An MCP server that uses ICSharpCode.Decompiler to provide .NET assembly inspection tools. Lets LLMs list types, decompile C#, and view IL disassembly from compiled assemblies.

Prerequisites

• .NET 10 SDK

Build

dotnet build

Usage

The server communicates over stdio using the MCP protocol.

dotnet run [options]

Options

Option	Description
--reference-path <path>	Add assembly reference directory (repeatable)
-v, --verbose	Enable debug-level logging to stderr

Tools

list_types

List all types (classes, interfaces, structs, delegates, enums) in a .NET assembly, grouped by namespace.

Parameter	Required	Description
assemblyPath	yes	Path to the .dll or .exe
pattern	no	Regex to filter type names

list_members

Decompile a type to C# and list its members and nested types.

Parameter	Required	Description
assemblyPath	yes	Path to the .dll or .exe
typeName	yes	Fully qualified type name (e.g. Namespace.ClassName)

decompile

Decompile a type to C# source code.

Parameter	Required	Description
assemblyPath	yes	Path to the .dll or .exe
typeName	yes	Fully qualified type name

disassemble

Disassemble a type to IL (Intermediate Language) code.

Parameter	Required	Description
assemblyPath	yes	Path to the .dll or .exe
typeName	yes	Fully qualified type name

MCP Client Configuration

Claude Code

Add to your MCP settings:

{
  "mcpServers": {
    "ilspy": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/ILSpyMCP"]
    }
  }
}

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "ilspy": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/ILSpyMCP"]
    }
  }
}

To pass additional options (e.g. reference paths for framework assemblies):

{
  "mcpServers": {
    "ilspy": {
      "command": "dotnet",
      "args": [
        "run", "--project", "/path/to/ILSpyMCP",
        "--",
        "--reference-path", "/path/to/framework/assemblies"
      ]
    }
  }
}