# ASP.NET Core Debugger — MCP Server for AI Agents

An MCP server that gives AI agents interactive debugging for .NET and ASP.NET Core through netcoredbg and DAP. It pauses code, reads runtime values, and tests fixes live.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed · ★ 15
- Author: magna-nz
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/magna-nz/aspnetcore-debugger-mcp
- Updated: 2026-09-14
- HTML: https://affpapa.org/en/nevibecode/mcp/aspnet-core-debugger-mcp-server-for-ai-agents

## What it does

The server bridges MCP clients with netcoredbg using the Debug Adapter Protocol (DAP). The agent attaches directly to the running .NET process instead of guessing from static code. It can pause execution, inspect parameters in EF Core queries, evaluate authentication claims, and examine live call stacks.

It provides 27 tools. These composite tools combine complex DAP workflows into agent-ready actions: `hang_analyze` identifies deadlocks across blocked threads, while `exception_autopsy` dissects active failures. The agent can also alter variable values during pause, validating potential fixes without recompiling or restarting the app.

Installing the tool requires the .NET 10 SDK. Prebuilt `netcoredbg` binaries come bundled for Linux, macOS, and Windows across x64 and arm64, removing the need for a separate debugger build.

## Install

### Claude Code (native platform)

**Install**
- The MCP registry has no launch command for it: see the repository README

## When to use it
- diagnose thread deadlocks in hung ASP.NET Core applications
- inspect generated EF Core SQL queries and bound parameters at runtime
- verify incoming claims during token validation failures
- modify variable values in memory to confirm a bugfix without rebuilding
- trace execution bottlenecks across internal request pipelines

## Example prompts
- Attach to the running service and run `hang_analyze` to see why the request is blocked
- Set a breakpoint inside the authentication handler and inspect the token claims
- Pause on the next pricing calculation, change discount to 100, and resume execution

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md