fix(tui): enable VT input mode on Windows (#1495)

This fixes Shift+Tab not being recognized correctly

package-lock.json

@@ -18,7 +18,8 @@
 			"dependencies": {
 				"@mariozechner/jiti": "^2.6.5",
 				"@mariozechner/pi-coding-agent": "^0.30.2",
-				"get-east-asian-width": "^1.4.0"
+				"get-east-asian-width": "^1.4.0",
+				"koffi": "^2.15.1"
 			},
 			"devDependencies": {
 				"@biomejs/biome": "2.3.5",
@@ -6120,6 +6121,16 @@
 				"node": ">= 12"
 			}
 		},
+		"node_modules/koffi": {
+			"version": "2.15.1",
+			"resolved": "https://registry.npmjs.org/koffi/-/koffi-2.15.1.tgz",
+			"integrity": "sha512-mnc0C0crx/xMSljb5s9QbnLrlFHprioFO1hkXyuSuO/QtbpLDa0l/uM21944UfQunMKmp3/r789DTDxVyyH6aA==",
+			"hasInstallScript": true,
+			"license": "MIT",
+			"funding": {
+				"url": "https://liberapay.com/Koromix"
+			}
+		},
 		"node_modules/lie": {
 			"version": "3.3.0",
 			"resolved": "https://registry.npmjs.org/lie/-/lie-3.3.0.tgz",
@@ -6383,7 +6394,6 @@
 			"resolved": "https://registry.npmjs.org/lit/-/lit-3.3.2.tgz",
 			"integrity": "sha512-NF9zbsP79l4ao2SNrH3NkfmFgN/hBYSQo90saIVI1o5GpjAdCPVstVzO1MrLOakHoEhYkrtRjPK6Ob521aoYWQ==",
 			"license": "BSD-3-Clause",
-			"peer": true,
 			"dependencies": {
 				"@lit/reactive-element": "^2.1.0",
 				"lit-element": "^4.2.0",
@@ -7742,7 +7752,6 @@
 			"resolved": "https://registry.npmjs.org/tailwind-merge/-/tailwind-merge-3.4.0.tgz",
 			"integrity": "sha512-uSaO4gnW+b3Y2aWoWfFpX62vn2sR3skfhbjsEnaBI81WD1wBLlHZe5sWf0AqjksNdYTbGBEd0UasQMT3SNV15g==",
 			"license": "MIT",
-			"peer": true,
 			"funding": {
 				"type": "github",
 				"url": "https://github.com/sponsors/dcastil"
@@ -7771,8 +7780,7 @@
 			"version": "4.1.18",
 			"resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.1.18.tgz",
 			"integrity": "sha512-4+Z+0yiYyEtUVCScyfHCxOYP06L5Ne+JiHhY2IjR2KWMIWhJOYZKLSGZaP5HkZ8+bY0cxfzwDE5uOmzFXyIwxw==",
-			"license": "MIT",
+			"license": "MIT"
-			"peer": true
 		},
 		"node_modules/tapable": {
 			"version": "2.3.0",
@@ -7890,7 +7898,6 @@
 			"resolved": "https://registry.npmjs.org/picomatch/-/picomatch-4.0.3.tgz",
 			"integrity": "sha512-5gTmgEY/sqK6gFXLIsQNH19lWb4ebPDLA4SdLP7dsWkIXHWlG66oPuVvXSGFPppYZz8ZDZq0dYYrbHfBCVUb1Q==",
 			"license": "MIT",
-			"peer": true,
 			"engines": {
 				"node": ">=12"
 			},
@@ -7987,7 +7994,6 @@
 			"integrity": "sha512-5C1sg4USs1lfG0GFb2RLXsdpXqBSEhAaA/0kPL01wxzpMqLILNxIxIOKiILz+cdg/pLnOUxFYOR5yhHU666wbw==",
 			"devOptional": true,
 			"license": "MIT",
-			"peer": true,
 			"dependencies": {
 				"esbuild": "~0.27.0",
 				"get-tsconfig": "^4.7.5"
@@ -8076,7 +8082,6 @@
 			"resolved": "https://registry.npmjs.org/vite/-/vite-7.3.1.tgz",
 			"integrity": "sha512-w+N7Hifpc3gRjZ63vYBXA56dvvRlNWRczTdmCBBa+CotUzAPf5b7YMdMR/8CQoeYE5LX3W4wj6RYTgonm1b9DA==",
 			"license": "MIT",
-			"peer": true,
 			"dependencies": {
 				"esbuild": "^0.27.0",
 				"fdir": "^6.5.0",
@@ -8191,7 +8196,6 @@
 			"resolved": "https://registry.npmjs.org/picomatch/-/picomatch-4.0.3.tgz",
 			"integrity": "sha512-5gTmgEY/sqK6gFXLIsQNH19lWb4ebPDLA4SdLP7dsWkIXHWlG66oPuVvXSGFPppYZz8ZDZq0dYYrbHfBCVUb1Q==",
 			"license": "MIT",
-			"peer": true,
 			"engines": {
 				"node": ">=12"
 			},
@@ -8710,6 +8714,7 @@
 				"@types/mime-types": "^2.1.4",
 				"chalk": "^5.5.0",
 				"get-east-asian-width": "^1.3.0",
+				"koffi": "^2.9.0",
 				"marked": "^15.0.12",
 				"mime-types": "^3.0.1"
 			},

package.json

@@ -45,7 +45,8 @@
 	"dependencies": {
 		"@mariozechner/jiti": "^2.6.5",
 		"@mariozechner/pi-coding-agent": "^0.30.2",
-		"get-east-asian-width": "^1.4.0"
+		"get-east-asian-width": "^1.4.0",
+		"koffi": "^2.15.1"
 	},
 	"overrides": {
 		"rimraf": "6.1.2",

packages/tui/package.json

@@ -39,6 +39,7 @@
 		"@types/mime-types": "^2.1.4",
 		"chalk": "^5.5.0",
 		"get-east-asian-width": "^1.3.0",
+		"koffi": "^2.9.0",
 		"marked": "^15.0.12",
 		"mime-types": "^3.0.1"
 	},

packages/tui/src/terminal.ts

@@ -1,4 +1,5 @@
 import * as fs from "node:fs";
+import koffi from "koffi";
 import { setKittyProtocolActive } from "./keys.js";
 import { StdinBuffer } from "./stdin-buffer.js";
 
@@ -86,6 +87,12 @@ export class ProcessTerminal implements Terminal {
 			process.kill(process.pid, "SIGWINCH");
 		}
 
+		// On Windows, enable ENABLE_VIRTUAL_TERMINAL_INPUT so the console sends
+		// VT escape sequences (e.g. \x1b[Z for Shift+Tab) instead of raw console
+		// events that lose modifier information. Must run AFTER setRawMode(true)
+		// since that resets console mode flags.
+		this.enableWindowsVTInput();
+
 		// Query and enable Kitty keyboard protocol
 		// The query handler intercepts input temporarily, then installs the user's handler
 		// See: https://sw.kovidgoyal.net/kitty/keyboard-protocol/
@@ -158,6 +165,31 @@ export class ProcessTerminal implements Terminal {
 		process.stdout.write("\x1b[?u");
 	}
 
+	/**
+	 * On Windows, add ENABLE_VIRTUAL_TERMINAL_INPUT (0x0200) to the stdin
+	 * console handle so the terminal sends VT sequences for modified keys
+	 * (e.g. \x1b[Z for Shift+Tab). Without this, libuv's ReadConsoleInputW
+	 * discards modifier state and Shift+Tab arrives as plain \t.
+	 */
+	private enableWindowsVTInput(): void {
+		if (process.platform !== "win32") return;
+		try {
+			const k32 = koffi.load("kernel32.dll");
+			const GetStdHandle = k32.func("void* __stdcall GetStdHandle(int)");
+			const GetConsoleMode = k32.func("bool __stdcall GetConsoleMode(void*, _Out_ uint32_t*)");
+			const SetConsoleMode = k32.func("bool __stdcall SetConsoleMode(void*, uint32_t)");
+
+			const STD_INPUT_HANDLE = -10;
+			const ENABLE_VIRTUAL_TERMINAL_INPUT = 0x0200;
+			const handle = GetStdHandle(STD_INPUT_HANDLE);
+			const mode = new Uint32Array(1);
+			GetConsoleMode(handle, mode);
+			SetConsoleMode(handle, mode[0]! | ENABLE_VIRTUAL_TERMINAL_INPUT);
+		} catch {
+			// koffi not available — Shift+Tab won't be distinguishable from Tab
+		}
+	}
+
 	async drainInput(maxMs = 1000, idleMs = 50): Promise<void> {
 		if (this._kittyProtocolActive) {
 			// Disable Kitty keyboard protocol first so any late key releases