T34: review round 2: bash 3.2 drops its DEBUG trap, which ran for key bindings, missed lone subshells and decided commands under extdebug, so it sends no C, and its D comes from the prompt by the command number; PowerShell takes a program's code only when the line's last pipeline ends in it, as its syntax tree and Get-Command name it; each check waits for the prompt before its line, so a repeated status is the line's own

assets/shell-integration/pwsh/elyterminal.ps1

@@ -11,7 +11,7 @@ function global:prompt {
             # Each native run sets a new $LASTEXITCODE, equal or not; strict mode refuses an unset one.
             $exit = Get-Variable LASTEXITCODE -Scope Global -ValueOnly -ErrorAction Ignore
             $ran = $null -ne $exit -and -not [object]::ReferenceEquals($exit, $global:ElyExit)
-            $code = if ($ran -and $exit -ne 0) { $exit } else { 1 }
+            $code = if ($global:ElyNative -and $ran -and $exit -ne 0) { $exit } else { 1 }
         }
         [Console]::Write("$esc]133;D;$code$bel")
         $global:ElyRan = $false
@@ -38,6 +38,20 @@ if (Test-Path Function:\PSConsoleHostReadLine) {
         if (-not [string]::IsNullOrWhiteSpace($line)) {
             $global:ElyRan = $true
             $global:ElyExit = Get-Variable LASTEXITCODE -Scope Global -ValueOnly -ErrorAction Ignore
+            # A program's exit code is the line's when the line's last pipeline ends in it.
+            $global:ElyNative = $false
+            $ast = [System.Management.Automation.Language.Parser]::ParseInput($line, [ref]$null, [ref]$null)
+            # Strict mode refuses .Count on one statement alone, so the statements stay a list.
+            $statements = @(if ($ast.EndBlock) { $ast.EndBlock.Statements })
+            $last = if ($statements.Count) { $statements[$statements.Count - 1] }
+            if ($last -is [System.Management.Automation.Language.PipelineAst]) {
+                $elements = $last.PipelineElements
+                $end = $elements[$elements.Count - 1]
+                $name = if ($end -is [System.Management.Automation.Language.CommandAst]) { $end.GetCommandName() }
+                $info = if ($name) { Get-Command -Name $name -ErrorAction Ignore | Select-Object -First 1 }
+                while ($info -and $info.CommandType -eq 'Alias') { $info = $info.ResolvedCommand }
+                $global:ElyNative = $null -ne $info -and $info.CommandType -in 'Application', 'ExternalScript'
+            }
             [Console]::Write("$([char]27)]133;C$([char]7)")
         }
         $line