diff --git a/apps/desktop/src/lib/shortcuts/hotkeys.test.ts b/apps/desktop/src/lib/shortcuts/hotkeys.test.ts
new file mode 100644
index 00000000000..504e50c0d45
--- /dev/null
+++ b/apps/desktop/src/lib/shortcuts/hotkeys.test.ts
@@ -0,0 +1,40 @@
+import { isSelectAllChord } from "$lib/shortcuts/hotkeys";
+import { describe, expect, test } from "vitest";
+
+function keydown(key: string, modifiers: { metaKey?: boolean; ctrlKey?: boolean } = {}) {
+	return new KeyboardEvent("keydown", { key, ...modifiers });
+}
+
+/** The values `Backend["platformName"]` takes where ⌘ is not the select-all modifier. */
+const NON_MAC_PLATFORMS = ["windows", "linux", "web"] as const;
+
+describe("isSelectAllChord", () => {
+	test("macOS selects all with cmd", () => {
+		expect(isSelectAllChord(keydown("a", { metaKey: true }), "macos")).toBe(true);
+	});
+
+	// Ctrl+A is the emacs "move to the start of the line" binding that macOS text fields have,
+	// so claiming it for select-all takes an editing key away instead of adding a shortcut.
+	test("macOS leaves ctrl alone", () => {
+		expect(isSelectAllChord(keydown("a", { ctrlKey: true }), "macos")).toBe(false);
+	});
+
+	test.each(NON_MAC_PLATFORMS)("%s selects all with ctrl", (platform) => {
+		expect(isSelectAllChord(keydown("a", { ctrlKey: true }), platform)).toBe(true);
+	});
+
+	// Cmd is not a select-all modifier off macOS, where that key is the Super/Windows key.
+	test.each(NON_MAC_PLATFORMS)("%s ignores meta", (platform) => {
+		expect(isSelectAllChord(keydown("a", { metaKey: true }), platform)).toBe(false);
+	});
+
+	test("a bare 'a' types rather than selects", () => {
+		expect(isSelectAllChord(keydown("a"), "macos")).toBe(false);
+		expect(isSelectAllChord(keydown("a"), "windows")).toBe(false);
+	});
+
+	test("the modifier only counts together with 'a'", () => {
+		expect(isSelectAllChord(keydown("b", { metaKey: true }), "macos")).toBe(false);
+		expect(isSelectAllChord(keydown("b", { ctrlKey: true }), "windows")).toBe(false);
+	});
+});
diff --git a/apps/desktop/src/lib/shortcuts/hotkeys.ts b/apps/desktop/src/lib/shortcuts/hotkeys.ts
index 84742c4f85e..89037a67da8 100644
--- a/apps/desktop/src/lib/shortcuts/hotkeys.ts
+++ b/apps/desktop/src/lib/shortcuts/hotkeys.ts
@@ -4,6 +4,22 @@ interface KeybindDefinitions {
 	[combo: string]: (event: KeyboardEvent) => void;
 }
 
+/**
+ * Whether `event` is `platform`'s "select all" chord.
+ *
+ * macOS selects all with ⌘ and leaves Ctrl+A as "move to the start of the line", the emacs
+ * binding its text fields carry everywhere else, so accepting either modifier there takes an
+ * editing key away rather than adding a shortcut. Everywhere else Ctrl is the one that selects.
+ *
+ * `platform` is a `Backend["platformName"]`, which the desktop app gets from the OS rather
+ * than from the user agent.
+ */
+export function isSelectAllChord(event: KeyboardEvent, platform: string): boolean {
+	if (event.key !== "a") return false;
+
+	return platform === "macos" ? event.metaKey : event.ctrlKey;
+}
+
 export const shortcuts = {
 	global: {
 		open_repository: {
diff --git a/apps/desktop/src/routes/+layout.svelte b/apps/desktop/src/routes/+layout.svelte
index 974c9796f50..efcff8d326c 100644
--- a/apps/desktop/src/routes/+layout.svelte
+++ b/apps/desktop/src/routes/+layout.svelte
@@ -22,7 +22,7 @@
 	import { fModeEnabled } from "$lib/config/uiFeatureFlags";
 	import { PROJECTS_SERVICE } from "$lib/project/projectsService";
 	import { TERMINAL_SERVICE } from "$lib/settings/terminalService";
-	import { createKeybind } from "$lib/shortcuts/hotkeys";
+	import { createKeybind, isSelectAllChord } from "$lib/shortcuts/hotkeys";
 	import { SHORTCUT_SERVICE } from "$lib/shortcuts/shortcutService";
 	import { CLIENT_STATE } from "$lib/state/clientState.svelte";
 	import { initUserSettings, UI_STATE } from "$lib/state/uiState.svelte";
@@ -114,14 +114,12 @@
 	// =============================================================================
 
 	function handleKeyDown(e: KeyboardEvent) {
-		// Explicitly detect cmd/ctrl + A since Tauri gets in the way of default behavior.
+		// Explicitly detect the select-all chord since Tauri gets in the way of default behavior.
 		// To get default behavior you can add a "Select All" predefined menu item to the
 		// Edit menu, but that prevents the event from reaching the webview.
 		if (
 			(e.target instanceof HTMLInputElement || e.target instanceof HTMLTextAreaElement) &&
-			(e.metaKey || e.ctrlKey) &&
-			e.key === "a" &&
-			e.target
+			isSelectAllChord(e, backend.platformName)
 		) {
 			e.target.select();
 			e.preventDefault();