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.
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
Tools (34)
Resources (4)
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
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License
AGPL-3.0 — see LICENSE for details.