fix(streams): keep Write-Progress visible to user, strip overlay from AI capture

Pre-fix v1.8.0 set $ProgressPreference = 'SilentlyContinue' inside the AI
command's invocation chain, which kept captured output clean but also
hid progress bars from the user watching the visible console — a
regression for AI-initiated long-running commands like
Compress-Archive and Invoke-WebRequest.

This change leaves $ProgressPreference at its default so the bar
renders on the visible terminal as usual. Each redraw of pwsh 7's
"Minimal" Progress view also writes the bar's text to Console.Out
(the visible cursor positioning happens via Win32 SetCursorPosition,
which doesn't hit our tee — only the bar's text bytes do). Those
bytes form a highly recognizable shape:

    \e[<sgr>;1m  <activity> [
    \e[7m  <status>  <padding>  \e[27m
    <padding>  ]  \e[0m

The reverse-video framing of the status (\e[7m...\e[27m) combined
with the bar's literal [ ... ] anchors is distinctive enough that no
legitimate user output coincidentally matches. Format-McpOutput
strips these blocks from the captured ConsoleOut buffer BEFORE the
generic VT-strip (so the inner SGR markers are still present to
anchor on), leaving the AI response clean.

Verified: progress bar visible on console for Compress-Archive,
nested progress (parent/child Ids), and long activity/status
strings. Captured AI response shows pipeline output only — no
=== CONSOLE.OUT (direct) === clutter. No leak into follow-up
commands. xunit + Pester suites still green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yotsuda

PowerShell.MCP/Resources/MCPPollingEngine.ps1

@@ -104,26 +104,18 @@ if (-not (Test-Path Variable:global:McpTimer)) {
             function Invoke-Captured {
                 [CmdletBinding()]
                 param([scriptblock]$Block)
-                # Suppress Write-Progress overlay during AI commands.
-                # Two reasons:
-                #   1. The AI cannot meaningfully consume a real-time
-                #      progress bar — the bar updates in place via
-                #      cursor manipulation, not as text the AI can read.
-                #      A static "10% done" snapshot delivered in the
-                #      tool response carries no value.
-                #   2. ConPTY leaks Progress redraw bytes into the next
-                #      command's Console.Out tee. The first command runs
-                #      Write-Progress, finishes; the second command
-                #      starts and ConPTY emits cleanup bytes for the
-                #      prior overlay, which our tee captures. The user
-                #      sees a CONSOLE.OUT section in command #2's
-                #      response containing the bar from command #1.
-                # Setting $ProgressPreference here scopes only to the
-                # AI command's invocation chain (PowerShell uses dynamic
-                # scope for preference variables), so user-typed
-                # commands at the visible terminal keep their normal
-                # progress display.
-                $ProgressPreference = 'SilentlyContinue'
+                # Write-Progress renders normally on the visible console
+                # so the user can see progress for AI-initiated
+                # long-running commands (Compress-Archive,
+                # Invoke-WebRequest, etc.). Each redraw of pwsh 7's
+                # "Minimal" Progress view also writes the bar's text to
+                # Console.Out, which our tee captures.
+                # Format-McpOutput's $progressOverlayPattern strips the
+                # overlay blocks (recognized by their reverse-video
+                # bracketed-status framing) from the captured ConsoleOut
+                # buffer before surfacing to the AI, so the response
+                # stays clean while the visible terminal keeps the
+                # animated bar.
                 & $Block
             }
 
@@ -557,10 +549,26 @@ if (-not (Test-Path Variable:global:McpTimer)) {
                 # If after stripping the result is whitespace only,
                 # surface as empty so the section is omitted entirely
                 # rather than rendering an empty header.
+                # pwsh 7's "Minimal" Progress view writes each redraw to
+                # Console.Out (not via cursor save/restore — the visible
+                # console position is fixed by Win32 SetCursorPosition,
+                # which doesn't go through our tee). The redraw bytes
+                # captured to ConsoleOut form a highly recognizable
+                # shape:
+                #   \e[<sgr>;1m  <activity> [
+                #   \e[7m  <status>  <padding>  \e[27m
+                #   <padding>  ]  \e[0m
+                # The reverse-video framing of the status (\e[7m...\e[27m)
+                # combined with the bar's literal [ ... ] is distinctive
+                # enough that no legitimate user output would coincidentally
+                # match it. Strip these blocks BEFORE the generic VT-strip
+                # so the inner SGR markers are still there to anchor on.
+                $progressOverlayPattern = "`e\[\d+(?:;\d+)*m[^`e]*?\[`e\[7m[^`e]*?`e\[27m[^`e]*?\]`e\[0m"
                 $cleanConsoleStream = {
                     param([string]$raw)
                     if (-not $raw) { return "" }
-                    $stripped = $raw -replace $vtPattern, ""
+                    $stripped = $raw -replace $progressOverlayPattern, ""
+                    $stripped = $stripped -replace $vtPattern, ""
                     $collapsed = $stripped -replace ' {8,}', '  '
                     $trimmed = $collapsed.TrimEnd("`r","`n", " ", "`t")
                     if ([string]::IsNullOrWhiteSpace($trimmed)) { return "" }

Staging/ReleaseNotes.md

@@ -13,7 +13,7 @@
 ## Improvements
 - Real-time streaming preserved through the new capture wiring — items render to the visible console as they arrive, not collected and rendered after the pipeline finishes.
 - Color preserved on the visible console for every stream type: red `Write-Error`, yellow `WARNING:`, yellow `VERBOSE:` / `DEBUG:` prefixes, and `Write-Host`'s user-chosen `ForegroundColor`.
-- `Write-Progress` is suppressed during AI-initiated commands. Real-time bar text is unreadable to the AI as a snapshot, and ConPTY was leaking progress redraw bytes into subsequent commands' captured output. User-typed commands at the visible terminal keep their normal progress display.
+- `Write-Progress` keeps rendering on the visible console for AI-initiated commands (`Compress-Archive`, `Invoke-WebRequest`, etc.) so the user can watch progress. Each redraw of pwsh 7's "Minimal" Progress view also writes the bar text to `Console.Out`; the polling engine recognizes those overlay blocks by their reverse-video bracketed-status framing (`\e[<sgr>m … [\e[7m … \e[27m … ]\e[0m`) and strips them from the captured `=== CONSOLE.OUT (direct) ===` buffer before surfacing to the AI, so the response stays clean.
 
 ## Internal
 - New `TeeTextWriter` for `[Console]::Out` / `[Console]::Error` tee, written to in parallel with the original streams so visible-console output is unaffected.