fix(tui): handle split Shift+Enter in VS Code

packages/tui/src/components/editor.ts

@@ -232,6 +232,7 @@ export class Editor implements Component {
 	// Bracketed paste mode buffering
 	private pasteBuffer: string = "";
 	private isInPaste: boolean = false;
+	private pendingShiftEnter: boolean = false;
 
 	// Prompt history for up/down navigation
 	private history: string[] = [];
@@ -422,6 +423,21 @@ export class Editor implements Component {
 			return;
 		}
 
+		if (this.pendingShiftEnter) {
+			if (data === "\r") {
+				this.pendingShiftEnter = false;
+				this.addNewLine();
+				return;
+			}
+			this.pendingShiftEnter = false;
+			this.insertCharacter("\\");
+		}
+
+		if (data === "\\") {
+			this.pendingShiftEnter = true;
+			return;
+		}
+
 		// Ctrl+C - let parent handle (exit/clear)
 		if (kb.matches(data, "copy")) {
 			return;

packages/tui/src/components/input.ts

@@ -16,6 +16,7 @@ export class Input implements Component {
 	// Bracketed paste mode buffering
 	private pasteBuffer: string = "";
 	private isInPaste: boolean = false;
+	private pendingShiftEnter: boolean = false;
 
 	getValue(): string {
 		return this.value;
@@ -63,6 +64,23 @@ export class Input implements Component {
 			}
 			return;
 		}
+
+		if (this.pendingShiftEnter) {
+			if (data === "\r") {
+				this.pendingShiftEnter = false;
+				if (this.onSubmit) this.onSubmit(this.value);
+				return;
+			}
+			this.pendingShiftEnter = false;
+			this.value = `${this.value.slice(0, this.cursor)}\\${this.value.slice(this.cursor)}`;
+			this.cursor += 1;
+		}
+
+		if (data === "\\") {
+			this.pendingShiftEnter = true;
+			return;
+		}
+
 		const kb = getEditorKeybindings();
 
 		// Escape/Cancel

packages/tui/test/editor.test.ts

@@ -275,6 +275,26 @@ describe("Editor component", () => {
 		});
 	});
 
+	describe("Shift+Enter handling", () => {
+		it("treats split VS Code Shift+Enter as a newline", () => {
+			const editor = new Editor(defaultEditorTheme);
+
+			editor.handleInput("\\");
+			editor.handleInput("\r");
+
+			assert.strictEqual(editor.getText(), "\n");
+		});
+
+		it("inserts a literal backslash when not followed by Enter", () => {
+			const editor = new Editor(defaultEditorTheme);
+
+			editor.handleInput("\\");
+			editor.handleInput("x");
+
+			assert.strictEqual(editor.getText(), "\\x");
+		});
+	});
+
 	describe("Unicode text editing behavior", () => {
 		it("inserts mixed ASCII, umlauts, and emojis as literal text", () => {
 			const editor = new Editor(defaultEditorTheme);

packages/tui/test/input.test.ts

@@ -0,0 +1,30 @@
+import assert from "node:assert";
+import { describe, it } from "node:test";
+import { Input } from "../src/components/input.js";
+
+describe("Input component", () => {
+	it("treats split VS Code Shift+Enter as submit", () => {
+		const input = new Input();
+		let submitted: string | undefined;
+
+		input.setValue("hello");
+		input.onSubmit = (value) => {
+			submitted = value;
+		};
+
+		input.handleInput("\\");
+		input.handleInput("\r");
+
+		assert.strictEqual(submitted, "hello");
+		assert.strictEqual(input.getValue(), "hello");
+	});
+
+	it("inserts a literal backslash when not followed by Enter", () => {
+		const input = new Input();
+
+		input.handleInput("\\");
+		input.handleInput("x");
+
+		assert.strictEqual(input.getValue(), "\\x");
+	});
+});