Aspnetcore Debugger MCP

What magna-nz/aspnetcore-debugger-mcp MCP server does

magna-nz/aspnetcore-debugger-mcp MCP server exposes interactive debugging for .NET and ASP.NET Core applications through MCP. It is intended for use with an AI client such as Claude, allowing the client to control a debugging session and inspect the target process while it runs.

The server covers common debugging workflows: starting or attaching to a process, continuing and pausing execution, stepping through code, setting and removing breakpoints, examining threads and stack frames, reading variables, evaluating expressions, and changing program state. Its higher-level operations include exception investigation, stack exploration, hang or deadlock analysis, and request tracing.

How it works

The MCP client communicates with the server over stdio using JSON-RPC. The server translates those requests into Debug Adapter Protocol operations and manages a child netcoredbg process. netcoredbg then debugs the target .NET process through the .NET debugging interfaces.

Several composite tools combine multiple lower-level debugger requests. For example, exception autopsy, stack exploration, hang analysis, and tracing are designed to return a more focused diagnosis than a sequence of individual protocol calls. Request tracing can instrument a request path, record timestamps and arguments at method entries, and resume execution so the developer can identify where time is spent.

The magna-nz/aspnetcore-debugger-mcp MCP server bundles platform-specific netcoredbg binaries, so a separate debugger installation is not required. Supported bundles cover Linux x64 and arm64, macOS Intel and Apple Silicon, and Windows x64.

Setup and configuration

Install the .NET global tool with the .NET 10 SDK available on the host:

dotnet tool install -g AspNetCoreDebuggerMcp --prerelease

Register the resulting aspnetcore-debugger-mcp executable with an MCP client. For Claude, the README shows either the Claude CLI or an MCP configuration entry:

{
  "mcpServers": {
    "aspnetcore-debugger": {
      "command": "aspnetcore-debugger-mcp"
    }
  }
}

The configuration can be project-scoped or global, and Claude Desktop can use its desktop configuration file. The /mcp command can be used in Claude to verify that the connection is present. The same global-tool installation approach is used across the supported operating systems.

Tools and capabilities

The documented tool groups include:

• Session control: launch, attach, disconnect, and inspect debugger state.
• Execution control: continue, pause, step, and wait for a breakpoint stop.
• Breakpoints: line, function, exception, and data breakpoints, plus listing and removal.
• Inspection: list threads, retrieve stack traces, read variables, set variables, evaluate expressions, and explore stacks.
• Diagnostics: inspect exceptions, analyze hangs or deadlocks, and trace request execution.

These capabilities support both targeted questions, such as checking the value of a parameter at a breakpoint, and broader investigations, such as locating a blocked thread or a slow call in an HTTP request.

Limitations and notes

The host must have the .NET 10 SDK installed. The bundled debugger binaries are limited to the operating-system and architecture combinations documented by the project: Linux x64 or arm64, macOS x64 or arm64, and Windows x64. The README describes the transport as local stdio rather than a hosted remote endpoint.

Changing variables or other runtime state is a debugging action, not a source-code modification; any confirmed fix still needs to be applied in the application code. The examples also show that request tracing and state mutation can affect execution, so they should be used with an understanding of the target environment.