PowerShell.Mcp Hijacks Consoles

[sharpninja]

Describe the bug
Sometimes the PS.MCP hijacks an existing console that it did not itself open.

To Reproduce
Steps to reproduce the behavior:

1. Open WindowsTerminal to a pwsh.exe session.
2. Wait for an AI Agent to request a console, it will take over the console opened in 1.

Expected behavior
Opening a pwsh.exe console myself should never get taken over.

Desktop (please complete the following information):

• OS: Windows 11

[yotsuda]

@sharpninja — thanks for the report, but I don't think this is a bug: that console was opted in without you realizing it.

The control channel lives inside the module — Import-Module PowerShell.MCP is what starts the named-pipe server in that process. A pwsh.exe that never imported it has no pipe to connect to, so there's nothing to hijack. And a console that did import it is adoptable on purpose: that's how "open a console, then hand it to the agent" works.

To confirm, in the console that reproduces it: Get-Module PowerShell.MCP. Or check the title — on import the module sets it to #<PID> ____ (the ____ is a placeholder until a tool call renames it to #<PID> <name>).

Then find the import: $PROFILE | Format-List * -Force and open each profile that exists. Your Windows Terminal profile's command line is worth a look too.

To keep a console un-adoptable, just keep the module out of it — pwsh -NoProfile, a guard around the import in your profile, or Remove-Module PowerShell.MCP.