Ilspy Decompile

This wraps ILSpy's command-line decompiler so Claude can inspect .NET assemblies for you. Point it at a DLL from NuGet packages, your build output, or the runtime itself, and it'll show you the actual C# implementation behind any API. Useful when documentation is thin or you need to understand why something behaves the way it does. The skill covers both standalone ilspycmd and the dnx version, walks through common assembly locations, and reminds you about gotchas like trimmed builds producing incomplete output. Just be aware that decompiling code you don't own can have licensing implications depending on what you're looking at.

skills.sh installs: 640
GitHub stars: 1.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add aaronontheweb/dotnet-skills --skill ilspy-decompile --agent claude-code

Installs into .claude/skills of the current project.

Files

.NET Assembly Decompilation with ILSpy

Use this skill to understand how .NET code works internally by decompiling compiled assemblies.

Prerequisites

.NET SDK installed
ILSpy command-line tool available via one of the following:
- dnx ilspycmd (if available in your SDK or runtime)
- dotnet tool install --global ilspycmd

Both forms are shown below. Use the one that works in your environment.

Note: ILSpyCmd options may vary slightly by version.
Always verify supported flags with ilspycmd -h.

Quick start

# Decompile an assembly to stdout
ilspycmd MyLibrary.dll
# or
dnx ilspycmd MyLibrary.dll

# Decompile to an output folder
ilspycmd -o output-folder MyLibrary.dll

Common .NET Assembly Locations

NuGet packages

~/.nuget/packages/<package-name>/<version>/lib/<tfm>/

.NET runtime libraries

dotnet --list-runtimes

.NET SDK reference assemblies

dotnet --list-sdks

Reference assemblies do not contain implementations.

Project build output

./bin/Debug/net8.0/<AssemblyName>.dll
./bin/Release/net8.0/publish/<AssemblyName>.dll

Core workflow

SKILL.md on GitHub

Details

Repository: github.com/aaronontheweb/dotnet-skills
Categories: Backend & APIs, .NET & C#
First seen: Jun 3, 2026