Start Comfy without a visible command prompt on the desktop.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/comfy-host-agent.mjs

@@ -2,8 +2,9 @@ import http from 'node:http'
 import net from 'node:net'
 import { execFile, spawn } from 'node:child_process'
 import { promisify } from 'node:util'
-import { readdirSync, existsSync, rmSync, readFileSync, openSync } from 'node:fs'
-import { basename, join, resolve, relative, isAbsolute } from 'node:path'
+import { readdirSync, existsSync, rmSync, readFileSync, openSync, mkdirSync, writeFileSync, unlinkSync } from 'node:fs'
+import { basename, dirname, join, resolve, relative, isAbsolute } from 'node:path'
+import { tmpdir } from 'node:os'
 
 const execFileAsync = promisify(execFile)
 const port = Number(process.env.COMFY_CONTROL_PORT || 8199)
@@ -235,10 +236,11 @@ function desktopShellCommand() {
 
 async function pythonMainUp() {
   try {
-    const { stdout } = await execFileAsync('wmic', [
-      'process', 'where', "name='python.exe'", 'get', 'commandline'
+    const { stdout } = await execFileAsync('powershell.exe', [
+      '-NoProfile', '-Command',
+      "Get-CimInstance Win32_Process | Where-Object { $_.CommandLine -match 'ComfyUI\\\\main.py|ComfyUI/main.py' } | Select-Object -First 1 -ExpandProperty ProcessId"
     ], { windowsHide: true, timeout: 6000 })
-    return /main\.py/i.test(String(stdout || ''))
+    return Boolean(String(stdout).trim())
   } catch {
     return false
   }
@@ -268,6 +270,70 @@ async function pickListenPort() {
   return preferred
 }
 
+function windowlessPython(pythonPath) {
+  if (process.platform !== 'win32') return pythonPath
+  if (!/python\.exe$/i.test(pythonPath)) return pythonPath
+  const pythonw = pythonPath.replace(/python\.exe$/i, 'pythonw.exe')
+  return existsSync(pythonw) ? pythonw : pythonPath
+}
+
+function vbsString(value) {
+  return `"${String(value).replace(/"/g, '""')}"`
+}
+
+function spawnViaWscript(file, args, opts = {}) {
+  const command = [file, ...args].map((part) => {
+    const text = String(part)
+    return /\s|"/.test(text) ? `"${text.replace(/"/g, '\\"')}"` : text
+  }).join(' ')
+  const lines = ['Set sh = CreateObject("WScript.Shell")']
+  if (opts.cwd) lines.push(`sh.CurrentDirectory = ${vbsString(opts.cwd)}`)
+  lines.push(`sh.Run ${vbsString(command)}, 0, False`)
+  const tmp = join(tmpdir(), `aigen-launch-${process.pid}-${Date.now()}.vbs`)
+  writeFileSync(tmp, `${lines.join('\r\n')}\r\n`)
+  const child = spawn('wscript.exe', ['//B', '//Nologo', tmp], {
+    detached: true,
+    stdio: 'ignore',
+    windowsHide: true
+  })
+  child.unref()
+  const cleanup = () => {
+    try { unlinkSync(tmp) } catch { /* ignore */ }
+  }
+  child.once('exit', cleanup)
+  setTimeout(cleanup, 15000)
+  return child
+}
+
+function spawnHidden(file, args, opts = {}) {
+  const exe = windowlessPython(file)
+  // python.exe + detached:true allocates an empty console on the active display.
+  // pythonw.exe is windowless. If it is missing, launch via hidden WScript.
+  if (process.platform === 'win32' && /python\.exe$/i.test(exe)) {
+    return spawnViaWscript(exe, args, opts)
+  }
+  const child = spawn(exe, args, {
+    detached: true,
+    stdio: opts.stdio || 'ignore',
+    windowsHide: true,
+    cwd: opts.cwd
+  })
+  child.unref()
+  return child
+}
+
+function spawnShellHidden(command, cwd) {
+  if (process.platform === 'win32') {
+    const match = String(command).match(/start\s+""\s+"([^"]+)"/i)
+      || String(command).match(/^"([^"]+\.exe)"\s*$/i)
+    if (match) return spawnHidden(match[1], [], { cwd })
+    return spawnViaWscript(process.env.ComSpec || 'cmd.exe', ['/d', '/s', '/c', command], { cwd })
+  }
+  const child = spawn(command, { shell: true, detached: true, stdio: 'ignore', cwd })
+  child.unref()
+  return child
+}
+
 async function startComfy() {
   markWork()
   const launch = resolveHeadlessLaunch()
@@ -277,15 +343,13 @@ async function startComfy() {
     if (portIdx >= 0) launch.args[portIdx + 1] = String(port)
     let stdio = 'ignore'
     try {
+      mkdirSync(dirname(launch.log), { recursive: true })
       stdio = ['ignore', openSync(launch.log, 'a'), openSync(launch.log, 'a')]
     } catch { /* ignore */ }
-    const child = spawn(launch.file, launch.args, {
-      detached: true,
+    const child = spawnHidden(launch.file, launch.args, {
       stdio,
-      windowsHide: true,
       cwd: launch.cwd
     })
-    child.unref()
     console.log(JSON.stringify({
       src: 'comfy-host-agent',
       event: 'start',
@@ -302,14 +366,7 @@ async function startComfy() {
     cwd: launch?.cwd || process.env.COMFY_LAUNCH_CWD || undefined,
     mode: launch?.mode || 'desktop-shell'
   }
-  const child = spawn(fallback.command, {
-    shell: true,
-    detached: true,
-    stdio: 'ignore',
-    windowsHide: true,
-    cwd: fallback.cwd
-  })
-  child.unref()
+  spawnShellHidden(fallback.command, fallback.cwd)
   console.log(JSON.stringify({
     src: 'comfy-host-agent',
     event: 'start',

server/utils/comfyLifecycle.ts

@@ -226,9 +226,15 @@ async function processRunning() {
 
 function spawnLaunchCommand(command: string) {
   log('spawn', { command: command.slice(0, 180) })
-  const child = spawn(command, {
+  const win = process.platform === 'win32'
+  const exe = win
+    ? command.match(/start\s+""\s+"([^"]+)"/i)?.[1] || command.match(/^"([^"]+\.exe)"\s*$/i)?.[1]
+    : ''
+  const child = exe
+    ? spawn(exe, [], { detached: true, stdio: 'ignore', windowsHide: true })
+    : spawn(command, {
       shell: true,
-    detached: true,
+      detached: !win,
       stdio: 'ignore',
       windowsHide: true
     })