fix(windows): stop console window flashes during scheduled scans

The schtasks /create action used to invoke the agent via a cmd /c
wrapper, which produced a visible cmd.exe flash on every scheduled
fire. This change:

- Drops the cmd /c wrapper; the task now invokes the agent (or the
  GUI-subsystem launcher) directly, with --install-dir / filelog
  handling moved into the binary.
- Adds cmd/stepsecurity-dev-machine-guard-task — a small
  GUI-subsystem launcher .exe used by the MSI install layout so
  Windows does not allocate a console for the scheduled task.
- Adds internal/winproc to suppress subprocess console flashes via
  CREATE_NO_WINDOW for child processes spawned by the agent.
- Wires the launcher binary into the MSI WiX manifest, .goreleaser
  config, Makefile, and the msi-smoke / release workflows.
- Adds Windows-side test coverage for schtasks, winproc, and the IDE
  detector.

Author: swarit-stepsecurity

.github/workflows/msi-smoke.yml

@@ -55,7 +55,7 @@ jobs:
           wix --version
           wix extension add --global WixToolset.Util.wixext/4.0.5
 
-      - name: Build Windows .exe
+      - name: Build Windows .exes (agent + launcher)
         shell: pwsh
         run: |
           $env:GOOS = "windows"
@@ -64,7 +64,11 @@ jobs:
           go build -trimpath -ldflags "-s -w" `
             -o "$PWD\dmg-smoke.exe" `
             ./cmd/stepsecurity-dev-machine-guard
-          Get-Item "$PWD\dmg-smoke.exe" | Select-Object Name, Length
+          go build -trimpath -ldflags "-s -w -H windowsgui" `
+            -o "$PWD\dmg-smoke-task.exe" `
+            ./cmd/stepsecurity-dev-machine-guard-task
+          Get-Item "$PWD\dmg-smoke.exe", "$PWD\dmg-smoke-task.exe" |
+            Select-Object Name, Length
 
       - name: Build MSI
         shell: pwsh
@@ -83,6 +87,7 @@ jobs:
             -d Arch=x64 `
             -d "Version=$version" `
             -d "BinaryPath=$PWD\dmg-smoke.exe" `
+            -d "LauncherPath=$PWD\dmg-smoke-task.exe" `
             -out "dist\dmg-smoke.msi"
           Get-Item "dist\dmg-smoke.msi" | Select-Object Name, Length
 
@@ -112,18 +117,28 @@ jobs:
       - name: Verify install artifacts
         shell: pwsh
         run: |
-          $bin   = "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard.exe"
-          $cfg   = "C:\ProgramData\StepSecurity\config.json"
-          $task  = "StepSecurity Dev Machine Guard"
+          $bin      = "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard.exe"
+          $launcher = "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard-task.exe"
+          $cfg      = "C:\ProgramData\StepSecurity\config.json"
+          $task     = "StepSecurity Dev Machine Guard"
 
           $checks = @()
 
-          # 1. Binary on disk
+          # 1a. Agent binary on disk
           if (Test-Path $bin) {
-            Write-Host "[OK] Binary present at $bin"
+            Write-Host "[OK] Agent present at $bin"
             $checks += $true
           } else {
-            Write-Host "::error::Binary missing: $bin"
+            Write-Host "::error::Agent missing: $bin"
+            $checks += $false
+          }
+
+          # 1b. Launcher binary on disk
+          if (Test-Path $launcher) {
+            Write-Host "[OK] Launcher present at $launcher"
+            $checks += $true
+          } else {
+            Write-Host "::error::Launcher missing: $launcher"
             $checks += $false
           }
 
@@ -160,7 +175,8 @@ jobs:
             $checks += $false
           }
 
-          # 4. Scheduled task registered and runs as INTERACTIVE
+          # 4. Scheduled task registered, runs as INTERACTIVE, and its
+          # action points at the launcher (not the agent directly).
           $taskInfo = schtasks /query /tn $task /v /fo LIST 2>&1
           if ($LASTEXITCODE -eq 0) {
             $runAs = ($taskInfo | Select-String -Pattern '^\s*Run As User:').ToString()
@@ -171,6 +187,15 @@ jobs:
               Write-Host "::error::Run As User wrong: $runAs"
               $checks += $false
             }
+
+            $action = ($taskInfo | Select-String -Pattern '^\s*Task To Run:').ToString()
+            if ($action -match 'stepsecurity-dev-machine-guard-task\.exe') {
+              Write-Host "[OK] Task action points at GUI launcher"
+              $checks += $true
+            } else {
+              Write-Host "::error::Task action does not point at launcher: $action"
+              $checks += $false
+            }
           } else {
             Write-Host "::error::schtasks /query failed: $taskInfo"
             $checks += $false
@@ -199,12 +224,17 @@ jobs:
         run: |
           $task = "StepSecurity Dev Machine Guard"
 
-          # Binary should be gone
-          if (Test-Path "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard.exe") {
-            Write-Host "::error::Binary still present after uninstall"
-            exit 1
+          # Both binaries should be gone
+          foreach ($leftover in @(
+            "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard.exe",
+            "C:\Program Files\StepSecurity\stepsecurity-dev-machine-guard-task.exe"
+          )) {
+            if (Test-Path $leftover) {
+              Write-Host "::error::File still present after uninstall: $leftover"
+              exit 1
+            }
           }
-          Write-Host "[OK] Binary removed"
+          Write-Host "[OK] Agent + launcher removed"
 
           # Scheduled task should be gone. Capture the exit code into a
           # local — PowerShell uses $LASTEXITCODE from the last native call

.github/workflows/release.yml

@@ -92,8 +92,13 @@ jobs:
         id: binaries
         run: |
           DARWIN=$(find dist -type f -name '*darwin_unnotarized' | head -1)
-          WIN_AMD64=$(find dist -type f -name '*.exe' -path '*windows_amd64*' | head -1)
-          WIN_ARM64=$(find dist -type f -name '*.exe' -path '*windows_arm64*' | head -1)
+          # Filter agent vs launcher (-task) explicitly — both ship as
+          # <name>-<version>-<os>_<arch>.exe so a bare *.exe glob would
+          # match either.
+          WIN_AMD64=$(find dist -type f -name 'stepsecurity-dev-machine-guard-*-windows_amd64.exe' ! -name '*-task-*' | head -1)
+          WIN_ARM64=$(find dist -type f -name 'stepsecurity-dev-machine-guard-*-windows_arm64.exe' ! -name '*-task-*' | head -1)
+          WIN_TASK_AMD64=$(find dist -type f -name 'stepsecurity-dev-machine-guard-task-*-windows_amd64.exe' | head -1)
+          WIN_TASK_ARM64=$(find dist -type f -name 'stepsecurity-dev-machine-guard-task-*-windows_arm64.exe' | head -1)
           LINUX_AMD64=$(find dist -type f -name 'stepsecurity-dev-machine-guard' -path '*linux_amd64*' | head -1)
           LINUX_ARM64=$(find dist -type f -name 'stepsecurity-dev-machine-guard' -path '*linux_arm64*' | head -1)
 
@@ -102,7 +107,7 @@ jobs:
           RPM_AMD64=$(find dist -type f -name '*-amd64.rpm' | head -1)
           RPM_ARM64=$(find dist -type f -name '*-arm64.rpm' | head -1)
 
-          for label in "darwin:${DARWIN}" "windows_amd64:${WIN_AMD64}" "windows_arm64:${WIN_ARM64}" "linux_amd64:${LINUX_AMD64}" "linux_arm64:${LINUX_ARM64}" "deb_amd64:${DEB_AMD64}" "deb_arm64:${DEB_ARM64}" "rpm_amd64:${RPM_AMD64}" "rpm_arm64:${RPM_ARM64}"; do
+          for label in "darwin:${DARWIN}" "windows_amd64:${WIN_AMD64}" "windows_arm64:${WIN_ARM64}" "windows_task_amd64:${WIN_TASK_AMD64}" "windows_task_arm64:${WIN_TASK_ARM64}" "linux_amd64:${LINUX_AMD64}" "linux_arm64:${LINUX_ARM64}" "deb_amd64:${DEB_AMD64}" "deb_arm64:${DEB_ARM64}" "rpm_amd64:${RPM_AMD64}" "rpm_arm64:${RPM_ARM64}"; do
             name="${label%%:*}"
             path="${label#*:}"
             if [ -z "$path" ] || [ ! -f "$path" ]; then
@@ -115,6 +120,8 @@ jobs:
           echo "darwin=$DARWIN" >> "$GITHUB_OUTPUT"
           echo "win_amd64=$WIN_AMD64" >> "$GITHUB_OUTPUT"
           echo "win_arm64=$WIN_ARM64" >> "$GITHUB_OUTPUT"
+          echo "win_task_amd64=$WIN_TASK_AMD64" >> "$GITHUB_OUTPUT"
+          echo "win_task_arm64=$WIN_TASK_ARM64" >> "$GITHUB_OUTPUT"
           echo "linux_amd64=$LINUX_AMD64" >> "$GITHUB_OUTPUT"
           echo "linux_arm64=$LINUX_ARM64" >> "$GITHUB_OUTPUT"
           echo "deb_amd64=$DEB_AMD64" >> "$GITHUB_OUTPUT"
@@ -147,6 +154,10 @@ jobs:
             "dist/stepsecurity-dev-machine-guard-windows_amd64.exe.bundle"
           sign_with_retry "${{ steps.binaries.outputs.win_arm64 }}" \
             "dist/stepsecurity-dev-machine-guard-windows_arm64.exe.bundle"
+          sign_with_retry "${{ steps.binaries.outputs.win_task_amd64 }}" \
+            "dist/stepsecurity-dev-machine-guard-task-windows_amd64.exe.bundle"
+          sign_with_retry "${{ steps.binaries.outputs.win_task_arm64 }}" \
+            "dist/stepsecurity-dev-machine-guard-task-windows_arm64.exe.bundle"
           sign_with_retry "${{ steps.binaries.outputs.linux_amd64 }}" \
             "dist/stepsecurity-dev-machine-guard-linux_amd64.bundle"
           sign_with_retry "${{ steps.binaries.outputs.linux_arm64 }}" \
@@ -168,6 +179,8 @@ jobs:
             dist/stepsecurity-dev-machine-guard-darwin_unnotarized.bundle \
             dist/stepsecurity-dev-machine-guard-windows_amd64.exe.bundle \
             dist/stepsecurity-dev-machine-guard-windows_arm64.exe.bundle \
+            dist/stepsecurity-dev-machine-guard-task-windows_amd64.exe.bundle \
+            dist/stepsecurity-dev-machine-guard-task-windows_arm64.exe.bundle \
             dist/stepsecurity-dev-machine-guard-linux_amd64.bundle \
             dist/stepsecurity-dev-machine-guard-linux_arm64.bundle \
             "${{ steps.binaries.outputs.deb_amd64 }}.bundle" \
@@ -183,6 +196,8 @@ jobs:
             ${{ steps.binaries.outputs.darwin }}
             ${{ steps.binaries.outputs.win_amd64 }}
             ${{ steps.binaries.outputs.win_arm64 }}
+            ${{ steps.binaries.outputs.win_task_amd64 }}
+            ${{ steps.binaries.outputs.win_task_arm64 }}
             ${{ steps.binaries.outputs.linux_amd64 }}
             ${{ steps.binaries.outputs.linux_arm64 }}
             ${{ steps.binaries.outputs.deb_amd64 }}
@@ -240,10 +255,15 @@ jobs:
         shell: pwsh
         run: |
           $version = "${{ needs.release.outputs.version }}"
-          $amd64 = Get-ChildItem dist -Filter "*-windows_amd64.exe" | Select-Object -First 1
-          $arm64 = Get-ChildItem dist -Filter "*-windows_arm64.exe" | Select-Object -First 1
-          if (-not $amd64 -or -not $arm64) {
-            Write-Error "Windows .exe assets missing under dist/"
+          # Both agent and launcher .exes share the *-windows_<arch>.exe
+          # suffix; filter on the -task- segment to tell them apart.
+          $amd64       = Get-ChildItem dist -Filter "stepsecurity-dev-machine-guard-*-windows_amd64.exe" | Where-Object Name -NotLike '*-task-*' | Select-Object -First 1
+          $arm64       = Get-ChildItem dist -Filter "stepsecurity-dev-machine-guard-*-windows_arm64.exe" | Where-Object Name -NotLike '*-task-*' | Select-Object -First 1
+          $taskAmd64   = Get-ChildItem dist -Filter "stepsecurity-dev-machine-guard-task-*-windows_amd64.exe" | Select-Object -First 1
+          $taskArm64   = Get-ChildItem dist -Filter "stepsecurity-dev-machine-guard-task-*-windows_arm64.exe" | Select-Object -First 1
+          if (-not $amd64 -or -not $arm64 -or -not $taskAmd64 -or -not $taskArm64) {
+            Write-Error "Windows .exe assets (agent + launcher, both arches) missing under dist/"
+            Get-ChildItem dist | Format-Table Name
             exit 1
           }
 
@@ -253,6 +273,7 @@ jobs:
             -d Arch=x64 `
             -d "Version=$version" `
             -d "BinaryPath=$($amd64.FullName)" `
+            -d "LauncherPath=$($taskAmd64.FullName)" `
             -out "dist/stepsecurity-dev-machine-guard-$version-x64.msi"
 
           wix build packaging/windows/Product.wxs `
@@ -261,6 +282,7 @@ jobs:
             -d Arch=arm64 `
             -d "Version=$version" `
             -d "BinaryPath=$($arm64.FullName)" `
+            -d "LauncherPath=$($taskArm64.FullName)" `
             -out "dist/stepsecurity-dev-machine-guard-$version-arm64.msi"
 
           Get-ChildItem dist -Filter "*.msi" | Format-Table Name, Length

.gitignore

@@ -28,3 +28,9 @@ stepsecurity-dev-machine-guard-linux
 
 # Temporary files
 todo-remove/
+
+# Agent runtime state. When the binary or its tests run from inside the
+# repo (working dir = a subpkg, HOME pointing under it, etc.), it drops
+# config.json, agent.error.log, ai-agent-hook-errors.jsonl, hooks-state.json
+# and friends here. Never artifacts we want to track.
+**/.stepsecurity/

.goreleaser.yml

@@ -23,6 +23,29 @@ builds:
     env:
       - CGO_ENABLED=0
 
+  # GUI-subsystem launcher invoked by Windows Task Scheduler so the
+  # console-subsystem agent never gets a console window allocated.
+  # -H windowsgui flips the PE subsystem; otherwise identical config.
+  - id: stepsecurity-dev-machine-guard-task
+    main: ./cmd/stepsecurity-dev-machine-guard-task
+    binary: stepsecurity-dev-machine-guard-task
+    goos:
+      - windows
+    goarch:
+      - amd64
+      - arm64
+    mod_timestamp: "{{ .CommitTimestamp }}"
+    flags:
+      - -trimpath
+    ldflags:
+      - -s -w
+      - -H windowsgui
+      - -X github.com/step-security/dev-machine-guard/internal/buildinfo.GitCommit={{.FullCommit}}
+      - -X github.com/step-security/dev-machine-guard/internal/buildinfo.ReleaseTag={{.Tag}}
+      - -X github.com/step-security/dev-machine-guard/internal/buildinfo.ReleaseBranch={{.Branch}}
+    env:
+      - CGO_ENABLED=0
+
 universal_binaries:
   - id: universal
     ids:
@@ -44,6 +67,13 @@ archives:
       - binary
     name_template: "stepsecurity-dev-machine-guard-{{ .Version }}-{{ .Os }}_{{ .Arch }}"
     allow_different_binary_count: true
+  - id: windows-task
+    ids:
+      - stepsecurity-dev-machine-guard-task
+    formats:
+      - binary
+    name_template: "stepsecurity-dev-machine-guard-task-{{ .Version }}-{{ .Os }}_{{ .Arch }}"
+    allow_different_binary_count: true
 
 nfpms:
   - id: linux-packages

Makefile

@@ -9,25 +9,34 @@ LDFLAGS := -s -w \
 	-X $(MODULE)/internal/buildinfo.ReleaseTag=$(TAG) \
 	-X $(MODULE)/internal/buildinfo.ReleaseBranch=$(BRANCH)
 
-.PHONY: build build-windows build-windows-arm64 build-linux deploy-windows test lint clean smoke build-msi-amd64 build-msi-arm64
+.PHONY: build build-windows build-windows-task build-windows-arm64 build-windows-task-arm64 build-linux deploy-windows test lint clean smoke build-msi-amd64 build-msi-arm64
 
 build:
 	go build -trimpath -ldflags "$(LDFLAGS)" -o $(BINARY) ./cmd/stepsecurity-dev-machine-guard
 
 build-windows:
 	GOOS=windows GOARCH=amd64 go build -trimpath -ldflags "$(LDFLAGS)" -o $(BINARY).exe ./cmd/stepsecurity-dev-machine-guard
 
+# GUI-subsystem launcher (see cmd/stepsecurity-dev-machine-guard-task).
+# `-H windowsgui` flips the PE subsystem so Windows doesn't allocate
+# a console when Task Scheduler launches it.
+build-windows-task:
+	GOOS=windows GOARCH=amd64 go build -trimpath -ldflags "$(LDFLAGS) -H windowsgui" -o $(BINARY)-task.exe ./cmd/stepsecurity-dev-machine-guard-task
+
 build-windows-arm64:
 	GOOS=windows GOARCH=arm64 go build -trimpath -ldflags "$(LDFLAGS)" -o $(BINARY)-arm64.exe ./cmd/stepsecurity-dev-machine-guard
 
+build-windows-task-arm64:
+	GOOS=windows GOARCH=arm64 go build -trimpath -ldflags "$(LDFLAGS) -H windowsgui" -o $(BINARY)-task-arm64.exe ./cmd/stepsecurity-dev-machine-guard-task
+
 build-linux:
 	GOOS=linux GOARCH=amd64 go build -trimpath -ldflags "$(LDFLAGS)" -o $(BINARY)-linux ./cmd/stepsecurity-dev-machine-guard
 
 # MSI builds. Require WiX 4 on PATH: `dotnet tool install --global wix --version 4.0.5`.
 # Output: dist/stepsecurity-dev-machine-guard-<version>-{x64,arm64}.msi
 # Reads Version from internal/buildinfo so MajorUpgrade semantics line up
 # with whatever the binary reports as `--version`.
-build-msi-amd64: build-windows
+build-msi-amd64: build-windows build-windows-task
 	mkdir -p dist
 	@wix extension list --global 2>/dev/null | grep -q "WixToolset.Util.wixext" || \
 		wix extension add --global WixToolset.Util.wixext/4.0.5
@@ -37,9 +46,10 @@ build-msi-amd64: build-windows
 		-d Arch=x64 \
 		-d Version=$(VERSION) \
 		-d BinaryPath=$(CURDIR)/$(BINARY).exe \
+		-d LauncherPath=$(CURDIR)/$(BINARY)-task.exe \
 		-out dist/stepsecurity-dev-machine-guard-$(VERSION)-x64.msi
 
-build-msi-arm64: build-windows-arm64
+build-msi-arm64: build-windows-arm64 build-windows-task-arm64
 	mkdir -p dist
 	@wix extension list --global 2>/dev/null | grep -q "WixToolset.Util.wixext" || \
 		wix extension add --global WixToolset.Util.wixext/4.0.5
@@ -49,6 +59,7 @@ build-msi-arm64: build-windows-arm64
 		-d Arch=arm64 \
 		-d Version=$(VERSION) \
 		-d BinaryPath=$(CURDIR)/$(BINARY)-arm64.exe \
+		-d LauncherPath=$(CURDIR)/$(BINARY)-task-arm64.exe \
 		-out dist/stepsecurity-dev-machine-guard-$(VERSION)-arm64.msi
 
 deploy-windows:
@@ -61,7 +72,7 @@ lint:
 	golangci-lint run ./...
 
 clean:
-	rm -f $(BINARY) $(BINARY).exe $(BINARY)-arm64.exe $(BINARY)-linux
+	rm -f $(BINARY) $(BINARY).exe $(BINARY)-task.exe $(BINARY)-arm64.exe $(BINARY)-task-arm64.exe $(BINARY)-linux
 	rm -rf dist/
 
 smoke: build