Rewrite Start-IshRemoteMcpServer loops forever on stdin EOF instead of exiting when a client closes the input stream

[ddemeyer]

Problem

Start-IshRemoteMcpServer never exits when the MCP client closes the stdio input stream
(EOF). The server spins in the while ($ActivateWhileLoop) loop forever, leaving orphaned
hidden pwsh processes behind.

Condition

Any client that shuts down by closing the server's stdin triggers it. The MCP stdio
transport spec (2026-07-28 and earlier bindings) states a server SHOULD exit promptly
when its reads return end-of-file.

Root cause

Start-IshRemoteMcpServer.ps1:58-59 treats EOF as an empty line:

$inputLine = [Console]::In.ReadLine()
if ([string]::IsNullOrEmpty($inputLine)) { continue }

ReadLine() returns $null on EOF. [string]::IsNullOrEmpty($null) is $true, so EOF
falls into the same continue branch as an empty line and the loop never breaks.

Solution

Break out of the loop on EOF, logging the shutdown first:

while ($ActivateWhileLoop) {
    $inputLine = [Console]::In.ReadLine()
    if ($null -eq $inputLine) {
        Write-IshRemoteLog -LogEntry @{ Level = 'Info'; Message = "stdin closed, exiting MCP Server" }
        break
    }
    if ([string]::IsNullOrEmpty($inputLine)) { continue }
    ...
}

$null -eq $inputLine is used (not -eq $null) so an empty line still goes through the
existing skip branch, while only true EOF ends the server.

Files

• Source/ISHRemote/Trisoft.ISHRemote/Scripts/Public/Start-IshRemoteMcpServer.ps1

Test plan

• Extend Start-IshRemoteMcpServer.Tests.ps1 with a case that redirects [Console]::In
  to an empty [System.IO.StringReader] (its first ReadLine() returns $null), saves
  the original reader first, calls
  Start-IshRemoteMcpServer -CmdletsToRegister @('Get-IshFolder') -ActivateWhileLoop $true,
  and asserts it returns (instead of hanging) and restores the original console input in a
  finally block.
• Manual check with a real MCP client: stop the client, confirm the hidden pwsh process
  exits.