dual-claude-launcher

Run two Claude Desktop windows in parallel, each with its own MCP server connection, enabling true concurrent AI-assisted task execution on Windows.

What This Is

Claude Desktop only runs one instance by default. This repo gives you a repeatable setup for launching a second (or more) isolated Claude window using a separate --user-data-dir, each connected to a different Desktop Commander MCP server. You can then run long tasks in both windows simultaneously — proven to work with overlapping timestamps across 2+ minute parallel runs.

How It Works

• Instance 1 — normal Claude Desktop (MSIX install), uses desktop-commander
• Instance 2 — launched via shortcut with --user-data-dir, uses desktop-commander-2
• Both instances connect to the same claude_desktop_config.json schema but live in separate profile directories
• Tasks run concurrently — no blocking between windows

Requirements

• Windows 11
• Claude Desktop (MSIX install)
• Node.js 18+
• uv (for OfficeMCP)
• Git + GitHub CLI (optional, for pushing)

Setup

1. Find your Claude exe path

Claude MSIX installs update automatically and change version folder. Run this to find the current path:

Get-Process | Where-Object {$_.Name -like "*claude*"} | Select-Object -First 1 -ExpandProperty Path

2. Create Instance 2 profile directory

New-Item -ItemType Directory -Path "$env:APPDATA\Claude-Instance2" -Force

3. Copy the config

Copy-Item config\claude_desktop_config.json "$env:APPDATA\Claude-Instance2\claude_desktop_config.json"

Edit the config to set your correct uvx.exe path for OfficeMCP.

4. Run the setup script

.\scripts\setup.ps1

This will:

• Auto-detect the current Claude exe path
• Create desktop shortcuts for Instance 1 and Instance 2
• Sync the config to Instance 2

Maintenance

After a Claude update (shortcuts break)

.\scripts\sync-shortcuts.ps1

After changing MCP config

.\scripts\sync-config.ps1

MCP Config

See config\claude_desktop_config.json for the full config template including:

• desktop-commander — Instance 1's MCP server
• desktop-commander-2 — Instance 2's MCP server
• officemcp — Office automation via uvx

Parallel Execution Convention

Window	MCP Server	Use For
Instance 1	desktop-commander	Primary / long-running tasks
Instance 2	desktop-commander-2	Secondary / parallel tasks

When prompting Instance 2, always say "use desktop-commander-2" explicitly.

Concurrency Test

To verify both instances are truly running in parallel:

Instance 1:

$out = "$env:USERPROFILE\Desktop\i1-log.txt"
1..120 | ForEach-Object { "I1-$_ - $(Get-Date -Format 'HH:mm:ss')" | Add-Content $out; Start-Sleep 1 }

Instance 2 (say this in Instance 2 chat):

Use desktop-commander-2 to run: $out = "C:\Users\YOU\Desktop\i2-log.txt"; 1..120 | ForEach-Object { "I2-$_ - $(Get-Date -Format 'HH:mm:ss')" | Add-Content $out; Start-Sleep 1 }

Check both files — you'll see interleaved timestamps proving true concurrency.

Repo Structure

dual-claude-launcher/
├── README.md
├── config/
│   └── claude_desktop_config.json    # MCP config template
└── scripts/
    ├── setup.ps1                     # First-time setup
    ├── sync-shortcuts.ps1            # Fix shortcuts after Claude update
    └── sync-config.ps1              # Push config changes to Instance 2

Known Issues

"Claude for Windows" onboarding popup appears occasionally

The MSIX Claude install registers itself as the handler for claude:// OAuth redirect URIs. When Instance 2 is running and any auth event fires, the OS sometimes prompts the main instance to handle it, briefly showing the onboarding/welcome screen. Just close it — it does not affect either instance. Cosmetic only, no fix currently.

Shortcuts break after Claude updates

MSIX auto-updates change the version folder (e.g. Claude_1.5354.0.0 → Claude_1.6608.0.0), breaking hardcoded shortcut paths. Run scripts\sync-shortcuts.ps1 after any update to auto-fix.

Repo Structure

dual-claude-launcher/
├── README.md
├── config/
│   └── claude_desktop_config.json    # MCP config template
└── scripts/
    ├── setup.ps1                     # First-time setup
    ├── sync-shortcuts.ps1            # Fix shortcuts after Claude update
    └── sync-config.ps1              # Push config changes to Instance 2