VS MCP Server

Model Context Protocol (MCP) server for Visual Studio — Enables AI agents like Claude Code to control Visual Studio features including debugging, building, editing, and UI automation.

This is a beta release. Feedback and bug reports are welcome on GitHub Issues.

100% AI Generated — All code in this project was generated entirely by AI (Claude).

Features

VS MCP Server exposes 115 tools across the following categories:

Tool Details

General

Solution

Project

Build

Editor

Edit Preview

Code Navigation

Solution Explorer

Debugger

Breakpoint

Output & Diagnostics

Console

UI Automation

Watch

Thread

Process

Immediate

Module

Register

Exception

Memory

Parallel

Web

Test

NuGet

Requirements

• Visual Studio 2019 (16.0 or later), Visual Studio 2022, or Visual Studio 2026 — Community, Professional, or Enterprise edition
• Windows
• .NET Framework 4.8
• .NET 8.0 Runtime (for the StdioProxy component)

Installation

1. Install the extension from Visual Studio Marketplace or download the .vsix file from Releases
2. Restart Visual Studio
3. The MCP server starts automatically when Visual Studio launches

Setup — Connecting with Claude Code

Note: %LOCALAPPDATA% is not recognized in bash. You must specify the full absolute path (e.g. C:\Users\<USERNAME>\AppData\Local\...).

Option A — CLI command:

claude mcp add vs-mcp -- "C:\Users\<USERNAME>\AppData\Local\VsMcp\bin\VsMcp.StdioProxy.exe"

Option B — Manual configuration (add to your MCP config JSON):

{
  "mcpServers": {
    "vs-mcp": {
      "command": "C:\\Users\\<USERNAME>\\AppData\\Local\\VsMcp\\bin\\VsMcp.StdioProxy.exe"
    }
  }
}

Architecture

The extension runs an HTTP-based MCP server inside Visual Studio. A lightweight StdioProxy bridges stdio-based MCP clients (like Claude Code) to the HTTP server, enabling seamless communication.

Claude Code  ──stdio──▶  StdioProxy  ──HTTP──▶  VS Extension
                          (relay)                (MCP server)

When Visual Studio is not running, the StdioProxy provides offline responses for basic protocol operations and returns cached tool definitions.

Multiple VS Instances

VS MCP Server supports multiple Visual Studio instances running simultaneously. Each VS instance registers itself via a port file (%LOCALAPPDATA%\VsMcp\server.<PID>.port) containing its HTTP port and the currently open solution path.

Instance Selection

StdioProxy selects which VS instance to connect to based on command-line arguments:

CWD-based Auto-Detection

When no --sln or --pid argument is provided, StdioProxy automatically discovers .sln files by walking up from the current working directory. This means that in most cases, no explicit configuration is needed — simply launching Claude Code from within a project directory is enough.

Configuration Examples

Single instance (auto-detect, no extra config needed):

claude mcp add vs-mcp -- "C:\Users\<USERNAME>\AppData\Local\VsMcp\bin\VsMcp.StdioProxy.exe"

Multiple instances (explicit solution-based — useful when CWD auto-detection is not sufficient):

{
  "mcpServers": {
    "vs-mcp-frontend": {
      "command": "C:\\Users\\<USERNAME>\\AppData\\Local\\VsMcp\\bin\\VsMcp.StdioProxy.exe",
      "args": ["--sln", "C:\\Projects\\Frontend\\Frontend.sln"]
    },
    "vs-mcp-backend": {
      "command": "C:\\Users\\<USERNAME>\\AppData\\Local\\VsMcp\\bin\\VsMcp.StdioProxy.exe",
      "args": ["--sln", "C:\\Projects\\Backend\\Backend.sln"]
    }
  }
}

Tool Filtering

Use the --tools argument to load only the tool categories you need. This reduces the number of tools exposed to the AI agent, which can improve token efficiency and response relevance.

Examples:

claude mcp add vs-mcp -- "C:\Users\<USERNAME>\AppData\Local\VsMcp\bin\VsMcp.StdioProxy.exe" --tools core,debug

{
  "mcpServers": {
    "vs-mcp": {
      "command": "C:\\Users\\<USERNAME>\\AppData\\Local\\VsMcp\\bin\\VsMcp.StdioProxy.exe",
      "args": ["--tools", "core,debug"]
    }
  }
}

You can also specify individual category names (e.g. --tools General,Build,Debugger). Omitting --tools loads all tools.

Reconnection

• If VS is restarted, StdioProxy automatically reconnects on the next tools/call request.
• Stale port files from crashed or closed VS instances are cleaned up automatically during discovery.

Showcase: hands-off AI-driven dogfood

With focus_guard_set enabled=true, an AI agent can drive a full build → debug → UI verification cycle in Visual Studio on one monitor while the developer keeps a fullscreen application (e.g. a game) running on another — no focus theft, no window flicker, no context switch.

Paired with jidodebugger — an upstream MCP server that sits above vs-mcp's desktop-app UIA layer and supersedes it with WPF-native automation (bridge injection into the debuggee, direct ICommand invocation, and ViewModel-property waits via wpf_bridge_inject / wpf_invoke_command / wpf_wait_for, on top of the raw UIA tools vs-mcp already provides) — the loop becomes: vs-mcp launches the debuggee under the focus guard, jidodebugger drives its UI over the same MCP session, and neither side has to touch the foreground.

Recorded end-to-end run against a WPF debuggee (6 tool calls, zero human interventions, zero foreground steals):

How it works under the hood, when the guard is on:

1. LockSetForegroundWindow denies foreign SetForegroundWindow calls during the debug-start window.
2. SPI_SETFOREGROUNDLOCKTIMEOUT is temporarily raised so the launched debuggee's own activation attempts are demoted to a taskbar flash.
3. If VS is minimized at the moment debug_start / debug_start_without_debugging / debug_restart is invoked, it is re-minimized (SW_SHOWMINNOACTIVE) whenever it tries to auto-restore during the lock window.

The setting is off by default, so opt-in via focus_guard_set before an autonomous session and turn it off again when you want normal VS focus behavior back.

Observability

When focus does slip through, you don't have to guess what took it. A background auditor (started automatically) records every foreground transition Windows fires — process name, window title, timestamp, and whether the guard was on. Call focus_guard_audit_read right after any perceived focus steal to see exactly which process / window pulled foreground and when, and focus_guard_audit_clear to reset the buffer before a new test scenario.

Bundled Claude Code Skills

The VS Extension ships a small set of Claude Code skills that complement the MCP tools. They are deployed automatically on extension startup to %USERPROFILE%\.claude\skills\, so Claude Code picks them up without manual setup.

Source files live under src/VsMcp.Extension/Skills/; edit them there and the extension will redeploy the updated copy on next launch (it compares file content and skips unchanged files).

Contributing

Pull Requests are not accepted.

For feature requests and bug reports, please use GitHub Issues.

License

MIT License