fix(terminal): use ctrl shift c for output copy

Capture Ctrl+Shift+C before xterm input handling and copy selected output through a browser-compatible fallback. Preserve Ctrl+C as terminal input.

apps/web/src/components/features/terminal/terminal.test.ts

@@ -33,25 +33,28 @@ describe("getTerminalScrollbackLimit", () => {
 });
 
 describe("shouldCopyTerminalSelection", () => {
-	it("copies a selected terminal region with Ctrl+C or Cmd+C", () => {
+	it("copies a selected terminal region with Ctrl+Shift+C", () => {
 		expect(
 			shouldCopyTerminalSelection(
-				{ ctrlKey: true, metaKey: false, key: "c" },
-				true,
-			),
-		).toBe(true);
-		expect(
-			shouldCopyTerminalSelection(
-				{ ctrlKey: false, metaKey: true, key: "C" },
+				{ ctrlKey: true, shiftKey: true, key: "c" },
 				true,
 			),
 		).toBe(true);
 	});
 
-	it("keeps Ctrl+C as a terminal interrupt without a selection", () => {
+	it("keeps Ctrl+C as a terminal interrupt", () => {
 		expect(
 			shouldCopyTerminalSelection(
-				{ ctrlKey: true, metaKey: false, key: "c" },
+				{ ctrlKey: true, shiftKey: false, key: "c" },
+				true,
+			),
+		).toBe(false);
+	});
+
+	it("does not copy without a selection", () => {
+		expect(
+			shouldCopyTerminalSelection(
+				{ ctrlKey: true, shiftKey: true, key: "c" },
 				false,
 			),
 		).toBe(false);

apps/web/src/components/features/terminal/terminal.tsx

@@ -69,12 +69,13 @@ export function shouldRetryWebSocketClose(code: number, reason: string): boolean
 }
 
 export function shouldCopyTerminalSelection(
-	event: Pick<KeyboardEvent, "ctrlKey" | "metaKey" | "key">,
+	event: Pick<KeyboardEvent, "ctrlKey" | "shiftKey" | "key">,
 	hasSelection: boolean,
 ): boolean {
 	return (
 		hasSelection &&
-		(event.ctrlKey || event.metaKey) &&
+		event.ctrlKey &&
+		event.shiftKey &&
 		event.key.toLowerCase() === "c"
 	);
 }
@@ -483,24 +484,26 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 			const copySelection = () => {
 				const selection = term.getSelection();
 				if (!selection) return;
-				const clipboard = navigator.clipboard;
-				if (clipboard) {
-					void clipboard.writeText(selection).catch(() => {
-						document.execCommand("copy");
-					});
-				} else {
-					document.execCommand("copy");
-				}
+
+				const textarea = document.createElement("textarea");
+				textarea.value = selection;
+				textarea.setAttribute("readonly", "");
+				textarea.style.position = "fixed";
+				textarea.style.opacity = "0";
+				document.body.appendChild(textarea);
+				textarea.select();
+				document.execCommand("copy");
+				textarea.remove();
 			};
-			term.attachCustomKeyEventHandler((event) => {
+			const handleBrowserCopyShortcut = (event: KeyboardEvent) => {
 				if (!shouldCopyTerminalSelection(event, term.hasSelection())) {
-					return true;
+					return;
 				}
 
 				event.preventDefault();
+				event.stopPropagation();
 				copySelection();
-				return false;
-			});
+			};
 
 			const handleBrowserPaste = (event: ClipboardEvent) => {
 				const text = event.clipboardData?.getData("text/plain");
@@ -513,6 +516,7 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 				pasteTextRef.current(text);
 			};
 			container.addEventListener("copy", handleBrowserCopy, true);
+			container.addEventListener("keydown", handleBrowserCopyShortcut, true);
 			container.addEventListener("paste", handleBrowserPaste, true);
 
 			// Mobile touch scroll.
@@ -761,6 +765,11 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 				);
 				if (touchCleanup) touchCleanup();
 				container.removeEventListener("copy", handleBrowserCopy, true);
+				container.removeEventListener(
+					"keydown",
+					handleBrowserCopyShortcut,
+					true,
+				);
 				container.removeEventListener("paste", handleBrowserPaste, true);
 				pasteTextRef.current = () => {};
 				bracketedPasteEnabledRef.current = false;

openspec/changes/fix-web-terminal-clipboard/change.md

@@ -6,7 +6,8 @@ Users cannot reliably copy terminal output from the browser terminal. Browser co
 
 ## Required behavior
 
-- Copying a selected terminal region with standard browser shortcuts (`Ctrl/Cmd+C`) copies text to the system clipboard without sending an interrupt to the terminal.
+- Copying a selected terminal region with `Ctrl+Shift+C` copies text to the system clipboard without sending input to the terminal.
+- `Ctrl+C` remains a terminal interrupt, including when output is selected.
 - Copy requests expose the xterm selection as plain text.
 - Pasting plain text is handled once and follows bracketed-paste mode when enabled.
 - Normal terminal interrupts still work when there is no active selection.