Hide CLI console window on Windows across all SDKs (#329)

* Initial plan

* Add hide_cli_window option to suppress console window on Windows

Co-authored-by: patniko <26906478+patniko@users.noreply.github.com>

* Address code review feedback: use conditional kwargs and idiomatic assertions

Co-authored-by: patniko <26906478+patniko@users.noreply.github.com>

* Make hiding CLI window default behavior across all SDKs

- Python: Always hide window on Windows (removed hide_cli_window option)
- Node.js: Add windowsHide: true to spawn options
- Go: Add SysProcAttr with HideWindow on Windows via platform-specific files
- .NET: Already had CreateNoWindow = true

This ensures consistent behavior across all SDKs where the CLI subprocess
console window is hidden on Windows to avoid distracting users in GUI apps.

Co-authored-by: SteveSandersonMS <1101362+SteveSandersonMS@users.noreply.github.com>

* Fix Go build

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: patniko <26906478+patniko@users.noreply.github.com>
Co-authored-by: SteveSandersonMS <1101362+SteveSandersonMS@users.noreply.github.com>
Co-authored-by: Steve Sanderson <SteveSandersonMS@users.noreply.github.com>

Author: 3 people

go/client.go

@@ -1056,6 +1056,9 @@ func (c *Client) startCLIServer(ctx context.Context) error {
 
 	c.process = exec.CommandContext(ctx, command, args...)
 
+	// Configure platform-specific process attributes (e.g., hide window on Windows)
+	configureProcAttr(c.process)
+
 	// Set working directory if specified
 	if c.options.Cwd != "" {
 		c.process.Dir = c.options.Cwd

go/process_other.go

@@ -0,0 +1,11 @@
+//go:build !windows
+
+package copilot
+
+import "os/exec"
+
+// configureProcAttr configures platform-specific process attributes.
+// On non-Windows platforms, this is a no-op.
+func configureProcAttr(cmd *exec.Cmd) {
+	// No special configuration needed on non-Windows platforms
+}

go/process_windows.go

@@ -0,0 +1,16 @@
+//go:build windows
+
+package copilot
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// configureProcAttr configures platform-specific process attributes.
+// On Windows, this hides the console window to avoid distracting users in GUI apps.
+func configureProcAttr(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		HideWindow: true,
+	}
+}

nodejs/src/client.ts

@@ -1053,12 +1053,14 @@ export class CopilotClient {
                     stdio: stdioConfig,
                     cwd: this.options.cwd,
                     env: envWithoutNodeDebug,
+                    windowsHide: true,
                 });
             } else {
                 this.cliProcess = spawn(this.options.cliPath, args, {
                     stdio: stdioConfig,
                     cwd: this.options.cwd,
                     env: envWithoutNodeDebug,
+                    windowsHide: true,
                 });
             }
 

python/copilot/client.py

@@ -1167,6 +1167,9 @@ async def _start_cli_server(self) -> None:
         if self.options.get("github_token"):
             env["COPILOT_SDK_AUTH_TOKEN"] = self.options["github_token"]
 
+        # On Windows, hide the console window to avoid distracting users in GUI apps
+        creationflags = subprocess.CREATE_NO_WINDOW if sys.platform == "win32" else 0
+
         # Choose transport mode
         if self.options["use_stdio"]:
             args.append("--stdio")
@@ -1179,6 +1182,7 @@ async def _start_cli_server(self) -> None:
                 bufsize=0,
                 cwd=self.options["cwd"],
                 env=env,
+                creationflags=creationflags,
             )
         else:
             if self.options["port"] > 0:
@@ -1190,6 +1194,7 @@ async def _start_cli_server(self) -> None:
                 stderr=subprocess.PIPE,
                 cwd=self.options["cwd"],
                 env=env,
+                creationflags=creationflags,
             )
 
         # For stdio mode, we're ready immediately