mcilspy

What Can You Do?

Find Hardcoded Secrets

Search for URLs, API keys, connection strings, and credentials embedded in compiled .NET assemblies.

Reverse Engineer Binaries

List types, explore namespaces, and understand the structure of any .NET assembly without source code.

Recover Lost Source Code

Decompile entire assemblies back to compilable C# projects — with PDB generation and original variable names.

Analyze Malware Behavior

Safe static analysis of suspicious .NET executables. Find network calls, hardcoded URLs, and obfuscated logic.

Understand Third-Party Libraries

Read the actual implementation of any .NET library when documentation falls short. Extract assemblies from NuGet packages for bulk analysis.

Install

pip

pip install mcilspy

uvx

uvx mcilspy

Claude Code

claude mcp add ilspy -- mcilspy

Claude Desktop

{
  "mcpServers": {
    "ilspy": {
      "command": "mcilspy"
    }
  }
}

Then ask your assistant:

“Decompile the LoginService class from this assembly and explain what it does”

16 Tools, Two Engines

mcilspy ships 7 metadata tools that work immediately — no .NET SDK required. They parse PE headers and metadata tables directly via dnfile. Install ilspycmd to unlock 9 more tools for full decompilation, diagrams, and project generation.

Tool	Purpose	Requires ilspycmd
decompile_assembly	Full C# source recovery with PDB support	Yes
decompile_method	Extract a specific method from a type	Yes
list_types	Enumerate classes, interfaces, structs, enums	Yes
search_types	Find types by name pattern (regex supported)	Yes
search_strings	Find hardcoded strings in IL code	No
search_methods	Find methods by name or pattern	No
search_fields	Find fields and constants	No
search_properties	Find properties by name	No
list_events	List all event definitions	No
list_resources	Find embedded files and images	No
get_metadata_summary	Assembly statistics and references	No
generate_diagrammer	Interactive HTML type relationship diagrams	Yes
dump_package	Extract assemblies from NuGet packages	Yes
get_assembly_info	Version, framework, signing info	Yes
check_ilspy_installation	Diagnose setup issues	No
install_ilspy	Auto-install .NET SDK + ilspycmd	No