fix(windows): hide bash helper consoles

closes #4699

packages/agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed tail truncation for oversized single-line output that ends with a trailing newline ([#4715](https://github.com/earendil-works/pi/issues/4715)).
+- Fixed Windows Node execution environment command spawns to hide helper console windows from background processes ([#4699](https://github.com/earendil-works/pi/issues/4699)).
 
 ## [0.75.3] - 2026-05-18
 

packages/agent/src/harness/env/nodejs.ts

@@ -108,7 +108,10 @@ async function runCommand(
 		let stdout = "";
 		let child: ReturnType<typeof spawn>;
 		try {
-			child = spawn(command, args, { stdio: ["ignore", "pipe", "ignore"] });
+			child = spawn(command, args, {
+				stdio: ["ignore", "pipe", "ignore"],
+				windowsHide: true,
+			});
 		} catch {
 			resolve({ stdout: "", status: null });
 			return;
@@ -192,6 +195,7 @@ function killProcessTree(pid: number): void {
 			spawn("taskkill", ["/F", "/T", "/PID", String(pid)], {
 				stdio: "ignore",
 				detached: true,
+				windowsHide: true,
 			});
 		} catch {
 			// Ignore errors.
@@ -275,6 +279,7 @@ export class NodeExecutionEnv implements ExecutionEnv {
 					detached: process.platform !== "win32",
 					env: getShellEnv(this.shellEnv, options?.env),
 					stdio: ["ignore", "pipe", "pipe"],
+					windowsHide: true,
 				});
 			} catch (error) {
 				const cause = toError(error);

packages/coding-agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed the subagent extension's parallel mode to return useful per-task output and failed-task diagnostics to the parent model instead of 100-character previews ([#4710](https://github.com/earendil-works/pi/issues/4710)).
+- Fixed Windows local bash execution to hide helper console windows when launched from background SDK processes ([#4699](https://github.com/earendil-works/pi/issues/4699)).
 
 ## [0.75.3] - 2026-05-18
 

packages/coding-agent/src/core/tools/bash.ts

@@ -76,6 +76,7 @@ export function createLocalBashOperations(options?: { shellPath?: string }): Bas
 					detached: process.platform !== "win32",
 					env: env ?? getShellEnv(),
 					stdio: ["ignore", "pipe", "pipe"],
+					windowsHide: true,
 				});
 				if (child.pid) trackDetachedChildPid(child.pid);
 				let timedOut = false;

packages/coding-agent/src/utils/shell.ts

@@ -15,7 +15,11 @@ function findBashOnPath(): string | null {
 	if (process.platform === "win32") {
 		// Windows: Use 'where' and verify file exists (where can return non-existent paths)
 		try {
-			const result = spawnSync("where", ["bash.exe"], { encoding: "utf-8", timeout: 5000 });
+			const result = spawnSync("where", ["bash.exe"], {
+				encoding: "utf-8",
+				timeout: 5000,
+				windowsHide: true,
+			});
 			if (result.status === 0 && result.stdout) {
 				const firstMatch = result.stdout.trim().split(/\r?\n/)[0];
 				if (firstMatch && existsSync(firstMatch)) {
@@ -190,6 +194,7 @@ export function killProcessTree(pid: number): void {
 			spawn("taskkill", ["/F", "/T", "/PID", String(pid)], {
 				stdio: "ignore",
 				detached: true,
+				windowsHide: true,
 			});
 		} catch {
 			// Ignore errors if taskkill fails