diff --git a/agent/lsp/client.py b/agent/lsp/client.py
index 9207cb75bdaa..3411f5300b34 100644
--- a/agent/lsp/client.py
+++ b/agent/lsp/client.py
@@ -56,6 +56,8 @@ from pathlib import Path
 from typing import Any, Awaitable, Callable, Dict, List, Optional, Set
 from urllib.parse import quote, unquote
 
+from hermes_cli._subprocess_compat import windows_hide_flags
+
 from agent.lsp.protocol import (
     ERROR_CONTENT_MODIFIED,
     ERROR_METHOD_NOT_FOUND,
@@ -294,6 +296,12 @@ class LSPClient:
         cmd = self._command
         if sys.platform == "win32":
             cmd = self._win_wrap_cmd(cmd)
+        # Suppress the cmd.exe console window that would otherwise flash
+        # every time we launch a ``.cmd``-wrapped language server
+        # (e.g. pyright-langserver.CMD) from a console-less host such as
+        # a VS Code/Zed extension running the ACP adapter.
+        # windows_hide_flags() is CREATE_NO_WINDOW on Windows, 0 on POSIX.
+        creationflags = windows_hide_flags()
 
         try:
             # start_new_session=True detaches the LSP server into its own
@@ -312,6 +320,7 @@ class LSPClient:
                 env=env,
                 cwd=self._cwd,
                 start_new_session=True,
+                creationflags=creationflags,
             )
         except FileNotFoundError as e:
             raise LSPProtocolError(
diff --git a/agent/lsp/install.py b/agent/lsp/install.py
index 079033b772ad..68a9751e7fa9 100644
--- a/agent/lsp/install.py
+++ b/agent/lsp/install.py
@@ -35,6 +35,8 @@ import threading
 from pathlib import Path
 from typing import Any, Dict, Optional
 
+from hermes_cli._subprocess_compat import windows_hide_flags
+
 logger = logging.getLogger("agent.lsp.install")
 
 # Package-name → install-strategy hint registry.  Each entry is a
@@ -268,6 +270,7 @@ def _install_npm(
             text=True,
             timeout=300,
             stdin=subprocess.DEVNULL,
+            creationflags=windows_hide_flags(),
         )
         if proc.returncode != 0:
             logger.warning(
@@ -317,6 +320,7 @@ def _install_go(pkg: str, bin_name: str) -> Optional[str]:
             timeout=600,
             env=env,
             stdin=subprocess.DEVNULL,
+            creationflags=windows_hide_flags(),
         )
         if proc.returncode != 0:
             logger.warning(
diff --git a/contributors/emails/hellofrommorgan@users.noreply.github.com b/contributors/emails/hellofrommorgan@users.noreply.github.com
new file mode 100644
index 000000000000..0787203fc7b1
--- /dev/null
+++ b/contributors/emails/hellofrommorgan@users.noreply.github.com
@@ -0,0 +1 @@
+hellofrommorgan