ASP.NET Core Debugging MCP Server is an MIT-licensed MCP server designed to enable AI agents (such as Claude, Cursor, etc.) to directly debug .NET / ASP.NET Core applications. It is built on netcoredbg and combines the capabilities of the Debug Adapter Protocol (DAP) with agent-oriented composite tools, enabling AI to actually run code, pause execution, read runtime values, modify state to test fixes, and give answers based on real observations rather than mere guesses.
In terms of main capabilities, the server provides 27 tools, covering breakpoint setting, stepping, thread inspection, exception analysis, deadlock analysis, and request tracing, among others. It includes some composite tools, such as exception_autopsy, stack_explore, hang_analyze, and tracing tools, which bundle multiple DAP requests into a single tool call, making them easier for agents to use. In addition, it provides the ability to automatically instrument the request pipeline, helping to pinpoint the time consumption of slow requests.
In terms of usage, installation takes only three steps: first, the .NET 10 SDK is required, then install via dotnet tool install -g AspNetCoreDebuggerMcp --prerelease (the package already bundles prebuilt netcoredbg for linux-x64, linux-arm64, win-x64, osx-x64, and osx-arm64, so no separate installation is needed). Next, register it with Claude, either by using the CLI command claude mcp add aspnetcore-debugger -- aspnetcore-debugger-mcp, or by editing the configuration file (.mcp.json, ~/.claude.json, or claude_desktop_config.json) to add the following content: { "mcpServers": { "aspnetcore-debugger": { "command": "aspnetcore-debugger-mcp" } } }. Finally, you can converse with Claude, confirm the connection via /mcp, and then describe the debugging needs, and the agent will automatically select the appropriate tools.
Applicable scenarios include: diagnosing why an EF Core query returns empty results, troubleshooting a JWT authentication issue returning 401, testing fixes without restarting the application, analyzingapplication hangs (such as sync-over-async deadlocks), and pinpointing the time consumption of slow requests, among others. For example, the agent can pause inside UserRepository.GetActiveAsync to read the SQL actually sent by EF Core, or break inside JwtBearerHandler.HandleAuthenticateAsync to inspect the claims seen by the authentication handler.
In terms of limitations, the host needs to have the .NET 10 SDK installed, and the MCP server itself is a cross-platform .NET global tool. Known limitations also include certain limitations of some debug adapters and tracing, which are mentioned in the specific documentation but not detailed here. In addition, the project is built on netcoredbg (MIT) and the ModelContextProtocol SDK (MIT). Compared with another debug-mcp project, this project is MIT-licensed and cross-platform, while debug-mcp goes deeper into runtime internals but is Linux-only and AGPL.
