diff --git a/packages/core/platform/core-provider.tsx b/packages/core/platform/core-provider.tsx
index 21f07e518f..34bee14bf5 100644
--- a/packages/core/platform/core-provider.tsx
+++ b/packages/core/platform/core-provider.tsx
@@ -18,7 +18,10 @@ import { defaultStorage } from "./storage";
 import { AuthInitializer } from "./auth-initializer";
 import type { CoreProviderProps, ClientIdentity } from "./types";
 import type { StorageAdapter } from "../types/storage";
-import { configureShortcutPlatform } from "../shortcuts/platform";
+import {
+  configureShortcutPlatform,
+  configureShortcutRuntime,
+} from "../shortcuts/platform";
 
 // Module-level singletons — created once at first render, never recreated.
 // Vite HMR preserves module-level state, so these survive hot reloads.
@@ -43,6 +46,11 @@ function initCore(
       ? identity.os
       : null,
   );
+  // Authoritative override; before this runs (module-eval store hydration)
+  // detectShortcutRuntime() reads the preload globals and already agrees.
+  configureShortcutRuntime(
+    identity?.platform === "desktop" ? "desktop" : null,
+  );
 
   const api = new ApiClient(apiBaseUrl, {
     logger: createLogger("api"),
diff --git a/packages/core/shortcuts/definitions.test.ts b/packages/core/shortcuts/definitions.test.ts
index 2defda5bd0..7fb7e5d9d2 100644
--- a/packages/core/shortcuts/definitions.test.ts
+++ b/packages/core/shortcuts/definitions.test.ts
@@ -9,7 +9,13 @@ import {
   shortcutFromEvent,
   shortcutMatchesEvent,
 } from "./definitions";
-import { configureShortcutPlatform, detectShortcutPlatform } from "./platform";
+import {
+  configureShortcutPlatform,
+  configureShortcutRuntime,
+  detectShortcutPlatform,
+  detectShortcutRuntime,
+  getShortcutRuntime,
+} from "./platform";
 
 function keyEvent(
   key: string,
@@ -27,6 +33,7 @@ function keyEvent(
 
 afterEach(() => {
   configureShortcutPlatform(null);
+  configureShortcutRuntime(null);
   vi.unstubAllGlobals();
 });
 
@@ -128,6 +135,83 @@ describe("keyboard shortcut definitions", () => {
     ).toBe(false);
   });
 
+  it("reserves browser-owned accelerators on web but frees the bare chords on desktop", () => {
+    for (const key of ["P", "L", "T", "N", "D", "U"]) {
+      const chord = createShortcutChord(key, { primary: true });
+      expect(isReservedShortcut(chord, "macos", "web")).toBe(true);
+      expect(isReservedShortcut(chord, "windows", "web")).toBe(true);
+      expect(isReservedShortcut(chord, "macos", "desktop")).toBe(false);
+      expect(isReservedShortcut(chord, "windows", "desktop")).toBe(false);
+      // Only the bare primary chord opens up — extra modifiers keep the
+      // historical reservation on every runtime.
+      for (const extra of [{ shift: true }, { alt: true }, { control: true }]) {
+        const variant = createShortcutChord(key, { primary: true, ...extra });
+        expect(isReservedShortcut(variant, "macos", "desktop")).toBe(true);
+        expect(isReservedShortcut(variant, "macos", "web")).toBe(true);
+      }
+    }
+    // OS-owned combos that motivated the narrowing must stay reserved on
+    // desktop: Option+Cmd+D toggles the macOS Dock, Ctrl+Alt+T opens a
+    // terminal on common Linux desktops.
+    expect(
+      isReservedShortcut(
+        createShortcutChord("D", { primary: true, alt: true }),
+        "macos",
+        "desktop",
+      ),
+    ).toBe(true);
+    expect(
+      isReservedShortcut(
+        createShortcutChord("T", { primary: true, alt: true }),
+        "linux",
+        "desktop",
+      ),
+    ).toBe(true);
+  });
+
+  it("keeps app-owned and editing accelerators reserved on desktop", () => {
+    for (const key of ["W", "R", "Q", "A", "C", "V", "X", "Y", "Z", "0", "Minus", "Plus"]) {
+      expect(
+        isReservedShortcut(createShortcutChord(key, { primary: true }), "macos", "desktop"),
+      ).toBe(true);
+    }
+    expect(isReservedShortcut(createShortcutChord("F5"), "windows", "desktop")).toBe(true);
+    expect(
+      isReservedShortcut(createShortcutChord("Space", { primary: true }), "macos", "desktop"),
+    ).toBe(true);
+  });
+
+  it("allows recording bare Cmd/Ctrl+P for an action on desktop only", () => {
+    const cmdP = createShortcutChord("P", { primary: true });
+    expect(isShortcutAllowedForAction("openSearch", cmdP, "macos", "desktop")).toBe(true);
+    expect(isShortcutAllowedForAction("openSearch", cmdP, "macos", "web")).toBe(false);
+    expect(isShortcutAllowedForAction("goIssues", cmdP, "windows", "desktop")).toBe(true);
+    // Modifier variants keep the historical reservation even on desktop.
+    expect(
+      isShortcutAllowedForAction(
+        "openSearch",
+        createShortcutChord("P", { primary: true, shift: true }),
+        "macos",
+        "desktop",
+      ),
+    ).toBe(false);
+    // Send stays locked to Enter / Mod+Enter regardless of runtime.
+    expect(isShortcutAllowedForAction("send", cmdP, "macos", "desktop")).toBe(false);
+  });
+
+  it("detects the desktop runtime from preload globals with a configure override", () => {
+    expect(detectShortcutRuntime()).toBe("web");
+    vi.stubGlobal("window", { desktopAPI: {} });
+    expect(detectShortcutRuntime()).toBe("desktop");
+    vi.stubGlobal("window", { electron: {} });
+    expect(detectShortcutRuntime()).toBe("desktop");
+    vi.stubGlobal("window", {});
+    expect(detectShortcutRuntime()).toBe("web");
+    expect(getShortcutRuntime()).toBe("web");
+    configureShortcutRuntime("desktop");
+    expect(getShortcutRuntime()).toBe("desktop");
+  });
+
   it("rejects modifier-only, composition-only, and unidentified key events", () => {
     for (const key of ["Fn", "CapsLock", "Dead", "Process", "Unidentified"]) {
       expect(shortcutFromEvent(keyEvent(key), "macos")).toBeNull();
diff --git a/packages/core/shortcuts/definitions.ts b/packages/core/shortcuts/definitions.ts
index 1282558a34..10bdb69edf 100644
--- a/packages/core/shortcuts/definitions.ts
+++ b/packages/core/shortcuts/definitions.ts
@@ -1,6 +1,8 @@
 import {
   getShortcutPlatform,
+  getShortcutRuntime,
   type ShortcutPlatform,
+  type ShortcutRuntime,
 } from "./platform";
 
 export type ShortcutActionId =
@@ -236,21 +238,42 @@ export function isEditableShortcutTarget(target: EventTarget | null): boolean {
 }
 
 const PRIMARY_RESERVED_KEYS = new Set([
-  // Window/browser operations.
-  "W", "R", "L", "T", "N", "P", "Q", "D", "U",
+  // Window operations the app itself owns on every runtime: W closes the
+  // tab, R/F5 is the reload guard, Q quits.
+  "W", "R", "Q",
   // Fundamental editing operations should never become product actions.
   "A", "C", "V", "X", "Y", "Z",
+  // Zoom accelerators: fixed app shortcuts on desktop, browser zoom on web.
   "Equals", "Plus", "Minus", "Underscore", "0",
 ]);
 
-/** Browser/window/OS accelerators that cannot be reliably owned by the app. */
+// Accelerators owned by the browser UI around a tab: print, address bar,
+// new tab/window, bookmark, view source. A web page cannot reliably own
+// them, but the Electron renderer receives the bare primary chords as plain
+// keydowns — neither Electron's default menu nor the desktop shell binds
+// any of them — so exactly those are recordable on desktop (MUL-4457).
+// Variants with extra modifiers stay reserved on both runtimes: several
+// belong to the OS or window manager (Option+Cmd+D toggles the macOS Dock,
+// Ctrl+Alt+T opens a terminal on common Linux desktops), which even the
+// desktop app cannot own.
+const BROWSER_ONLY_PRIMARY_RESERVED_KEYS = new Set([
+  "P", "L", "T", "N", "D", "U",
+]);
+
+/** Browser/window/OS accelerators the app cannot reliably own in `runtime`. */
 export function isReservedShortcut(
   shortcut: ShortcutChord,
   platform: ShortcutPlatform = getShortcutPlatform(),
+  runtime: ShortcutRuntime = getShortcutRuntime(),
 ): boolean {
   const { modifiers, key } = shortcut;
   if (key === "F5") return true;
   if (modifiers.primary && PRIMARY_RESERVED_KEYS.has(key)) return true;
+  if (modifiers.primary && BROWSER_ONLY_PRIMARY_RESERVED_KEYS.has(key)) {
+    const barePrimary =
+      !modifiers.control && !modifiers.meta && !modifiers.alt && !modifiers.shift;
+    if (runtime !== "desktop" || !barePrimary) return true;
+  }
 
   if (platform === "macos") {
     if (modifiers.primary && (key === "Space" || key === "Tab" || key === "M" || key === "H")) return true;
@@ -292,9 +315,10 @@ export function isShortcutAllowedForAction(
   actionId: ShortcutActionId,
   shortcut: ShortcutChord,
   platform: ShortcutPlatform = getShortcutPlatform(),
+  runtime: ShortcutRuntime = getShortcutRuntime(),
 ): boolean {
   if (!isShortcutChordActionable(shortcut)) return false;
-  if (isReservedShortcut(shortcut, platform)) return false;
+  if (isReservedShortcut(shortcut, platform, runtime)) return false;
   // Tab is focus navigation (and Ctrl+Tab is browser tab navigation) on every
   // supported platform. It is never a dependable product-level binding.
   if (shortcut.key === "Tab") return false;
diff --git a/packages/core/shortcuts/index.ts b/packages/core/shortcuts/index.ts
index 800c119b42..883b2ebd74 100644
--- a/packages/core/shortcuts/index.ts
+++ b/packages/core/shortcuts/index.ts
@@ -18,9 +18,13 @@ export {
 } from "./definitions";
 export {
   configureShortcutPlatform,
+  configureShortcutRuntime,
   detectShortcutPlatform,
+  detectShortcutRuntime,
   getShortcutPlatform,
+  getShortcutRuntime,
   type ShortcutPlatform,
+  type ShortcutRuntime,
 } from "./platform";
 export {
   useShortcutStore,
diff --git a/packages/core/shortcuts/platform.ts b/packages/core/shortcuts/platform.ts
index 27fea6ecb6..ea428cf104 100644
--- a/packages/core/shortcuts/platform.ts
+++ b/packages/core/shortcuts/platform.ts
@@ -1,6 +1,10 @@
 export type ShortcutPlatform = "macos" | "windows" | "linux" | "unknown";
 
+/** Where shortcut handling runs: a browser tab or the Electron renderer. */
+export type ShortcutRuntime = "web" | "desktop";
+
 let configuredPlatform: ShortcutPlatform | null = null;
+let configuredRuntime: ShortcutRuntime | null = null;
 
 function normalizePlatform(value: string): ShortcutPlatform {
   const platform = value.toLowerCase();
@@ -37,3 +41,35 @@ export function configureShortcutPlatform(
 export function getShortcutPlatform(): ShortcutPlatform {
   return configuredPlatform ?? detectShortcutPlatform();
 }
+
+/**
+ * Environment fallback, and unlike the OS it must be trustworthy at
+ * module-evaluation time: the shortcut store hydrates (and sanitizes
+ * persisted overrides) when its module first loads, before CoreProvider
+ * gets a chance to configure anything. That is safe because the desktop
+ * preload exposes its bridge globals before any renderer script runs.
+ * Same signals as `detectClientType` in ../analytics — not imported so
+ * this module stays dependency-free.
+ */
+export function detectShortcutRuntime(): ShortcutRuntime {
+  if (typeof window === "undefined") return "web";
+  const w = window as unknown as { electron?: unknown; desktopAPI?: unknown };
+  if (w.electron || w.desktopAPI) return "desktop";
+  if (
+    typeof navigator !== "undefined" &&
+    /Electron/i.test(navigator.userAgent)
+  ) {
+    return "desktop";
+  }
+  return "web";
+}
+
+export function configureShortcutRuntime(
+  runtime: ShortcutRuntime | null | undefined,
+): void {
+  configuredRuntime = runtime ?? null;
+}
+
+export function getShortcutRuntime(): ShortcutRuntime {
+  return configuredRuntime ?? detectShortcutRuntime();
+}
diff --git a/packages/core/shortcuts/store.test.ts b/packages/core/shortcuts/store.test.ts
index 5dbd0dfcc3..d6f21d6030 100644
--- a/packages/core/shortcuts/store.test.ts
+++ b/packages/core/shortcuts/store.test.ts
@@ -1,5 +1,6 @@
 import { afterEach, describe, expect, it } from "vitest";
 import { createShortcutChord } from "./definitions";
+import { configureShortcutRuntime } from "./platform";
 import {
   findShortcutConflict,
   getShortcut,
@@ -10,6 +11,7 @@ import {
 
 afterEach(() => {
   useShortcutStore.getState().resetAll();
+  configureShortcutRuntime(null);
 });
 
 describe("shortcut store", () => {
@@ -68,6 +70,21 @@ describe("shortcut store", () => {
     ).toEqual({});
   });
 
+  it("keeps browser-only bindings when the runtime is desktop", () => {
+    const cmdP = createShortcutChord("P", { primary: true });
+
+    configureShortcutRuntime("desktop");
+    expect(sanitizeShortcutOverrides({ openSearch: cmdP })).toEqual({
+      openSearch: cmdP,
+    });
+    useShortcutStore.getState().setShortcut("openSearch", cmdP);
+    expect(getShortcut("openSearch")).toEqual(cmdP);
+
+    // The same persisted value hydrating in a browser falls back to default.
+    configureShortcutRuntime("web");
+    expect(sanitizeShortcutOverrides({ openSearch: cmdP })).toEqual({});
+  });
+
   it("finds conflicts against defaults and overrides", () => {
     expect(
       findShortcutConflict(