ilspy-decompile

ilspy-decompile is a skill for Claude Code from Aaronontheweb/dotnet-skills. It costs 49 tokens per session (550 once invoked), scanned A, original, MIT.

A guide to using ILSpy to decompile .NET assemblies, which are compiled files containing .NET program code.

In plain words
What is it for?
Use it to examine compiled .NET libraries, locate assemblies, view API internals, and export decompiled code with the ILSpy command-line tool.
Why use it?
It helps developers inspect implementation details when source code is unavailable, including framework code and NuGet packages.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is ./bin/Debug/net8.0/<AssemblyName>.dll.

Part of the dotnet-skills plugin — 36 skills, 6 agents shipped together

not rated 1.1krepo +7 1mo ago A scan Socket: passSnyk: passSkillSpector: pass 49 tokens original MIT

Good fit Use it to examine compiled .NET libraries, locate assemblies, view API internals, and export decompiled code with the ILSpy command-line tool.

Compare 6 skills from other repositories ↓
About the project

.NET Skills is an AI coding plugin that provides skills and specialized guidance for professional .NET development, covering areas such as C#, Akka.NET, Aspire, Entity Framework Core, testing, and performance. .NET developers use it with coding assistants to apply production-oriented patterns while building and maintaining applications. The catalogue contains the plugin’s skills, agents, and instructions.

Aaronontheweb/dotnet-skills · 1,147 stars · on GitHub

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/Aaronontheweb/dotnet-skills
agentmods
npx agentmods add skills/aaronontheweb/dotnet-skills/ilspy-decompile

Made for: Claude Code.

Or install dotnet-skills, the plugin that ships this one along with the rest of its 36 skills, 6 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ilspy-decompile

README.md
[![agentmods](https://agentmods.dev/badge/skills/aaronontheweb/dotnet-skills/ilspy-decompile/github.svg)](https://agentmods.dev/skills/aaronontheweb/dotnet-skills/ilspy-decompile)
Your own site
<a href="https://agentmods.dev/skills/aaronontheweb/dotnet-skills/ilspy-decompile"><img src="https://agentmods.dev/badge/skills/aaronontheweb/dotnet-skills/ilspy-decompile/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ilspy-decompile

Your own site · 80×15
<a href="https://agentmods.dev/skills/aaronontheweb/dotnet-skills/ilspy-decompile"><img src="https://agentmods.dev/badge/skills/aaronontheweb/dotnet-skills/ilspy-decompile.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 550 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 18 Mar 2026
  • Snyk pass 16 Feb 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.00550
Opus 5 $0.00024 $0.00275
Sonnet 5 $0.00010 $0.00110
Haiku 4.5 $0.00005 $0.00055

Measured 10d ago against content hash aed579dde8ab, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

ilspy-decompile scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

skills/ilspy-decompile/SKILL.md · 103 lines

What it actually says

.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

  1. Identify what you want to understand
  2. Locate the assembly
  3. List types
  4. Decompile the target

Commands

Basic decompilation

ilspycmd MyLibrary.dll
ilspycmd -o ./decompiled MyLibrary.dll
ilspycmd -p -o ./project MyLibrary.dll

Targeted decompilation

ilspycmd -t Namespace.ClassName MyLibrary.dll
ilspycmd -lv CSharp12_0 MyLibrary.dll

View IL code

ilspycmd -il MyLibrary.dll

Notes on modern .NET builds

  • ReadyToRun images may reduce readability
  • Trimmed or AOT builds may omit code
  • Prefer non-trimmed builds

Decompiling assemblies may be subject to license restrictions.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 103 lines · 49 tokens per session scan A aed579dde8ab

Subscribe to this mod's changes

ilspy-decompile is a skill published in the GitHub repository Aaronontheweb/dotnet-skills (1,147 stars, last pushed 1mo ago), licensed MIT. It adds 49 tokens to every session and 550 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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