debug-mcp

★ 18

from jkolo

MCP server exposing .NET debugging as 34 AI-accessible tools via ICorDebug APIs — breakpoints, stepping, inspection, exception autopsy, and code analysis.

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debug-mcp.net

MCP server for .NET debugging — enable AI agents to debug .NET applications interactively.

What is debug-mcp?

debug-mcp is a Model Context Protocol server that exposes .NET debugging capabilities as structured API tools. It allows AI assistants like Claude, GPT, or Copilot to:

Launch or attach to .NET processes
Set breakpoints, exception breakpoints, and tracepoints
Step through code line by line
Inspect variables, evaluate expressions, and read memory
Analyze stack traces and threads
Get full exception context with one call (exception autopsy)
Navigate code with go-to-definition, find usages, and diagnostics
Automatically resolve symbols from public symbol servers

Unlike similar tools that use external debuggers via DAP protocol, debug-mcp interfaces directly with the .NET runtime using ICorDebug APIs — the same approach used by JetBrains Rider.

Tools (34)

Category	Tools	Description
Session	`debug_launch`, `debug_attach`, `debug_disconnect`, `debug_state`	Start, stop, and monitor debug sessions
Execution	`debug_continue`, `debug_pause`, `debug_step`	Control program flow
Breakpoints	`breakpoint_set`, `breakpoint_remove`, `breakpoint_list`, `breakpoint_enable`, `breakpoint_wait`	Set and manage source breakpoints
Exception Breakpoints	`breakpoint_set_exception`	Break on specific exception types (first/second chance)
Tracepoints	`tracepoint_set`	Non-blocking breakpoints that log messages without pausing
Exception Autopsy	`exception_get_context`	Full exception analysis: type, message, inner exceptions, stack frames with source, and local variables
Inspection	`threads_list`, `stacktrace_get`, `variables_get`, `evaluate`	Examine program state
Memory	`object_inspect`, `memory_read`, `layout_get`, `references_get`, `members_get`	Deep object and memory analysis
Modules	`modules_list`, `modules_search`, `types_get`	Explore loaded assemblies and types
Code Analysis	`code_load`, `code_goto_definition`, `code_find_usages`, `code_find_assignments`, `code_get_diagnostics`	Roslyn-powered code navigation and diagnostics
Process I/O	`process_write_input`, `process_read_output`	Interact with debuggee stdin/stdout

Resources (4)

URI	Description
`debugger://session`	Current debug session state
`debugger://breakpoints`	All active breakpoints
`debugger://threads`	Thread list with states
`debugger://source/{file}`	Source file contents

Documentation

Architecture — System design and components
How Debugging Works — ICorDebug internals explained
MCP Tools Reference — Complete API documentation
MCP Resources — Subscribable state views
Development Guide — Building, testing, contributing

Similar Projects

Project	Language	Approach	.NET Support
mcp-debugger	TypeScript	DAP	Via external debugger
dap-mcp	Python	DAP	Via external debugger
LLDB MCP	C++	Native	No
debug-mcp	C#	ICorDebug	Native, direct

Quick Start

Run

# No installation needed (.NET 10+)
dnx -y debug-mcp

Requirements

.NET 10 SDK or later
Linux (Windows and macOS support planned)

Configure with Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "dotnet-debugger": {
      "command": "dnx",
      "args": ["-y", "debug-mcp"]
    }
  }
}

Configure with Claude Code

Add to your .mcp.json:

{
  "mcpServers": {
    "dotnet-debugger": {
      "command": "dnx",
      "args": ["-y", "debug-mcp"]
    }
  }
}

Example Conversation

You: Debug my ASP.NET app and find why GetUser returns null

Claude: I'll launch your application and investigate.
        [Calls debug_launch with program path]
        [Calls breakpoint_set at UserService.cs:42]
        [Calls debug_continue]
        [Calls breakpoint_wait with 30s timeout]

        The breakpoint was hit. Let me check the variables.
        [Calls variables_get for current frame]

        I found the issue: the `userId` parameter is an empty string.
        The bug is in the calling code at line 28 where...

You: My app throws NullReferenceException somewhere in checkout. Find it.

Claude: I'll set an exception breakpoint and trigger the flow.
        [Calls debug_launch with program path]
        [Calls breakpoint_set_exception for System.NullReferenceException]
        [Calls debug_continue]
        [Calls breakpoint_wait with include_autopsy: true]

        Caught it! The exception was thrown in OrderService.cs at line 87.
        Here's the full context from the autopsy:
        - cart.Items was null because LoadCart() returned an empty cart
        - The null check at line 85 only checked cart, not cart.Items