mcp-windbg/docs/reference/plugin.md

Claude Code plugin

The plugin is the shortest way to use mcp-windbg from Claude Code. It brings the tools, a set of skills, and an agent, and it needs no pip install and no MCP configuration.

Install

/plugin marketplace add svnscha/mcp-windbg
/plugin install mcp-windbg-uvx@mcp-windbg

The first line registers this repository as a plugin marketplace; the second installs the plugin from it. Restart Claude Code if the tools do not appear straight away.

What you get

All ten tools, plus:

Skill	What it does
/mcp-windbg:analyze-dump	Triage a crash dump - exception, faulting frame, and what the evidence supports
/mcp-windbg:debug-remote	Attach to a running process through a WinDbg debug server
/mcp-windbg:kernel-debug	Drive a live kernel target, including resuming it and waiting for a break
/mcp-windbg:windbg-doctor	Check whether this machine can debug at all, and what to fix

And one agent:

• crash-analyst investigates a dump on its own and reports back a verdict, the evidence behind it, what it ruled out, and what to do next. Use it when a dump needs more than a first look, or to keep a long analysis out of your main conversation.

Ask for it by name: "use the crash-analyst agent on C:\dumps\app.dmp".

Requirements

• Windows. The server drives cdb.exe and kd.exe. A plugin manifest has no field for declaring a platform, so this is not enforced at install time - on macOS or Linux the plugin loads and the server then fails to find a debugger.
• Debugging Tools for Windows, for cdb.exe. Install WinDbg from the Microsoft Store, or the Windows SDK.
• uv, which provides uvx. This is the one prerequisite the plugin cannot supply for you: winget install astral-sh.uv.

Run /mcp-windbg:windbg-doctor if you are unsure - it checks all three and tells you what is missing.

How it runs the server

The plugin does not require the package to be installed. It launches the server with uvx, pinned to the release that matches the plugin version:

{
  "mcpServers": {
    "mcp-windbg": {
      "command": "uvx",
      "args": ["mcp-windbg@1.1.0"],
      "env": {
        "_NT_SYMBOL_PATH": "${_NT_SYMBOL_PATH:-SRV*C:\\Symbols*https://msdl.microsoft.com/download/symbols}"
      }
    }
  }
}

uvx fetches that version from PyPI on first use and caches it. Pinning keeps the plugin and the server it drives in step, so a plugin update is what moves the server version.

Symbols

Symbols work out of the box. The ${VAR:-default} form above means:

• No _NT_SYMBOL_PATH set - the plugin supplies the Microsoft symbol server, caching to C:\Symbols.
• _NT_SYMBOL_PATH already set - your value wins and the default is ignored. A symbol path you tuned yourself is never overwritten.

To use your own, set it in the environment before starting Claude Code:

setx _NT_SYMBOL_PATH "SRV*C:\Symbols*https://msdl.microsoft.com/download/symbols;C:\my\pdbs"

setx only affects new processes, so restart the terminal. Check what the server actually received with /mcp.

Without symbols, stacks resolve to module+0x1234 and any analysis built on them is guesswork - which is why the plugin defaults to something that works rather than to nothing.

Passing other options

The command-line options are set in the plugin's .mcp.json args. To add one - a custom --cdb-path, a --filter-script, a longer --timeout - edit that file in the installed plugin, or install the server directly instead (see Client configuration), which gives you full control of the command line at the cost of the bundled skills and agent.

Note that editing the installed copy is overwritten when the plugin updates.

Updating and removing

/plugin marketplace update mcp-windbg
/plugin update mcp-windbg-uvx@mcp-windbg

To remove it:

/plugin uninstall mcp-windbg-uvx@mcp-windbg
/plugin marketplace remove mcp-windbg

Not using uv

Install the package yourself and register the server directly. You lose the skills and the agent, but the tools are identical:

pip install mcp-windbg
claude mcp add mcp-windbg -s user -e _NT_SYMBOL_PATH="SRV*C:\Symbols*https://msdl.microsoft.com/download/symbols" -- python -m mcp_windbg