diff --git a/parallel_orchestrator.py b/parallel_orchestrator.py
index 60b4489..ab28ae6 100644
--- a/parallel_orchestrator.py
+++ b/parallel_orchestrator.py
@@ -593,14 +593,20 @@ class ParallelOrchestrator:
                 cmd.extend(["--model", self.model])
 
             try:
-                proc = subprocess.Popen(
-                    cmd,
-                    stdout=subprocess.PIPE,
-                    stderr=subprocess.STDOUT,
-                    text=True,
-                    cwd=str(AUTOCODER_ROOT),
-                    env={**os.environ, "PYTHONUNBUFFERED": "1"},
-                )
+                # CREATE_NO_WINDOW on Windows prevents console window pop-ups
+                # stdin=DEVNULL prevents blocking on stdin reads
+                popen_kwargs = {
+                    "stdin": subprocess.DEVNULL,
+                    "stdout": subprocess.PIPE,
+                    "stderr": subprocess.STDOUT,
+                    "text": True,
+                    "cwd": str(AUTOCODER_ROOT),
+                    "env": {**os.environ, "PYTHONUNBUFFERED": "1"},
+                }
+                if sys.platform == "win32":
+                    popen_kwargs["creationflags"] = subprocess.CREATE_NO_WINDOW
+
+                proc = subprocess.Popen(cmd, **popen_kwargs)
             except Exception as e:
                 debug_log.log("TESTING", f"FAILED to spawn testing agent: {e}")
                 return False, f"Failed to start testing agent: {e}"
@@ -644,14 +650,20 @@ class ParallelOrchestrator:
 
         print("Running initializer agent...", flush=True)
 
-        proc = subprocess.Popen(
-            cmd,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
-            text=True,
-            cwd=str(AUTOCODER_ROOT),
-            env={**os.environ, "PYTHONUNBUFFERED": "1"},
-        )
+        # CREATE_NO_WINDOW on Windows prevents console window pop-ups
+        # stdin=DEVNULL prevents blocking on stdin reads
+        popen_kwargs = {
+            "stdin": subprocess.DEVNULL,
+            "stdout": subprocess.PIPE,
+            "stderr": subprocess.STDOUT,
+            "text": True,
+            "cwd": str(AUTOCODER_ROOT),
+            "env": {**os.environ, "PYTHONUNBUFFERED": "1"},
+        }
+        if sys.platform == "win32":
+            popen_kwargs["creationflags"] = subprocess.CREATE_NO_WINDOW
+
+        proc = subprocess.Popen(cmd, **popen_kwargs)
 
         debug_log.log("INIT", "Initializer subprocess started", pid=proc.pid)
 
@@ -712,7 +724,7 @@ class ParallelOrchestrator:
             # CRITICAL: Kill the process tree to clean up any child processes (e.g., Claude CLI)
             # This prevents zombie processes from accumulating
             try:
-                _kill_process_tree(proc, timeout=2.0)
+                kill_process_tree(proc, timeout=2.0)
             except Exception as e:
                 debug_log.log("CLEANUP", f"Error killing process tree for {agent_type} agent", error=str(e))
             self._on_agent_complete(feature_id, proc.returncode, agent_type, proc)