mark electron renderer for codex bridge

apps/desktop/src/preload.cjs

@@ -33,4 +33,8 @@ const bridge = {
   }
 };
 
+contextBridge.exposeInMainWorld("islandflowDesktopRuntime", {
+  shell: "electron",
+  app: "islandflow"
+});
 contextBridge.exposeInMainWorld("islandflowDesktop", bridge);

apps/web/app/desktop-ai.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from "bun:test";
 
 import {
   createUnavailableState,
+  detectDesktopRuntimeMarker,
   detectDesktopShell,
   resolveDesktopAiRuntime,
 } from "./desktop-ai";
@@ -18,6 +19,22 @@ import {
 } from "./desktop-ai-panels";
 
 describe("desktop ai runtime detection", () => {
+  it("recognizes the explicit desktop preload marker before the bridge is available", () => {
+    const runtime = resolveDesktopAiRuntime({
+      islandflowDesktopRuntime: {
+        app: "islandflow",
+        shell: "electron",
+      },
+      navigator: {
+        userAgent: "Mozilla/5.0 Safari/537.36",
+      },
+    });
+
+    expect(runtime.shellAvailable).toBe(true);
+    expect(runtime.bridgeAvailable).toBe(false);
+    expect(runtime.bridge).toBeNull();
+  });
+
   it("recognizes Electron user agents before the bridge is available", () => {
     const runtime = resolveDesktopAiRuntime({
       navigator: {
@@ -102,8 +119,20 @@ describe("desktop action copy", () => {
 });
 
 describe("desktop shell detection", () => {
+  it("matches the explicit preload runtime marker", () => {
+    expect(
+      detectDesktopRuntimeMarker({ app: "islandflow", shell: "electron" }),
+    ).toBe(true);
+    expect(
+      detectDesktopRuntimeMarker({ app: "islandflow", shell: "browser" }),
+    ).toBe(false);
+  });
+
   it("matches Electron signatures", () => {
     expect(detectDesktopShell("Mozilla/5.0 Electron/39.0.0")).toBe(true);
+    expect(detectDesktopShell("Mozilla/5.0 IslandflowDesktop/0.1.0")).toBe(
+      true,
+    );
     expect(
       detectDesktopShell("Mozilla/5.0 Chrome/136.0.0.0 Safari/537.36"),
     ).toBe(false);

apps/web/app/desktop-ai.tsx

@@ -38,6 +38,10 @@ type DesktopAiRuntime = {
 
 declare global {
   interface Window {
+    islandflowDesktopRuntime?: {
+      app?: string | null;
+      shell?: string | null;
+    };
     islandflowDesktop?: DesktopAiBridge;
   }
 }
@@ -59,14 +63,28 @@ type DesktopAiContextValue = {
 
 const BRIDGE_POLL_INTERVAL_MS = 250;
 const BRIDGE_POLL_MAX_ATTEMPTS = 20;
-const ELECTRON_USER_AGENT_PATTERN = /\bElectron\/\S+/i;
+const ELECTRON_USER_AGENT_PATTERN = /\b(?:Electron|IslandflowDesktop)\/\S+/i;
 
 export const detectDesktopShell = (userAgent: string | null | undefined): boolean =>
   Boolean(userAgent && ELECTRON_USER_AGENT_PATTERN.test(userAgent));
 
+export const detectDesktopRuntimeMarker = (
+  runtime:
+    | {
+        app?: string | null;
+        shell?: string | null;
+      }
+    | null
+    | undefined
+): boolean => runtime?.app === "islandflow" && runtime.shell === "electron";
+
 export const resolveDesktopAiRuntime = (
   value:
     | {
+        islandflowDesktopRuntime?: {
+          app?: string | null;
+          shell?: string | null;
+        };
         islandflowDesktop?: DesktopAiBridge;
         navigator?: { userAgent?: string | null };
       }
@@ -75,7 +93,10 @@ export const resolveDesktopAiRuntime = (
 ): DesktopAiRuntime => {
   const bridge = value?.islandflowDesktop?.ai ? value.islandflowDesktop : null;
   const bridgeAvailable = Boolean(bridge?.ai);
-  const shellAvailable = bridgeAvailable || detectDesktopShell(value?.navigator?.userAgent);
+  const shellAvailable =
+    bridgeAvailable ||
+    detectDesktopRuntimeMarker(value?.islandflowDesktopRuntime) ||
+    detectDesktopShell(value?.navigator?.userAgent);
 
   return {
     shellAvailable,