diff --git a/app/(main)/[locale]/login/page.tsx b/app/(main)/[locale]/login/page.tsx
index d28ae4039..3ac336bd2 100644
--- a/app/(main)/[locale]/login/page.tsx
+++ b/app/(main)/[locale]/login/page.tsx
@@ -993,30 +993,34 @@ function LoginPageContent() {
   };
 
   /** The desktop build: the server's own sign-in page in the system browser. */
+  // Spelled out, not IS_DESKTOP_BUILD: only this form keeps the route out of other
+  // builds' bundles, which Lite's check on API strings relies on.
   const handleDesktopBrowserSignIn = async () => {
-    const target = jmapEndpoint.trim();
-    if (!target) {
-      setDesktopNotice(tDesktop("server_needed"));
-      return;
+    if (process.env.NEXT_PUBLIC_BULWARK_DESKTOP === '1') {
+      const target = jmapEndpoint.trim();
+      if (!target) {
+        setDesktopNotice(tDesktop("server_needed"));
+        return;
+      }
+      setDesktopNotice(null);
+      setDesktopWaiting(true);
+      const prefix = getPathPrefix(params.locale as string);
+      const outcome = await runDesktopBrowserSignIn({
+        serverUrl: target,
+        callbackPath: `${prefix}/${params.locale}/auth/callback`,
+        slot: useAccountStore.getState().getNextCookieSlot(),
+        remember: persistProviderSession,
+        addAccount: isAddAccountMode,
+      });
+      if (outcome.kind === "callback") {
+        window.location.href = outcome.callbackUrl;
+        return;
+      }
+      setDesktopWaiting(false);
+      if (outcome.kind === "unavailable") setDesktopNotice(tDesktop("browser_unavailable"));
+      else if (outcome.kind === "declined") setDesktopNotice(tDesktop("server_declined"));
+      else if (outcome.kind === "failed") setDesktopNotice(tDesktop("browser_failed"));
     }
-    setDesktopNotice(null);
-    setDesktopWaiting(true);
-    const prefix = getPathPrefix(params.locale as string);
-    const outcome = await runDesktopBrowserSignIn({
-      serverUrl: target,
-      callbackPath: `${prefix}/${params.locale}/auth/callback`,
-      slot: useAccountStore.getState().getNextCookieSlot(),
-      remember: persistProviderSession,
-      addAccount: isAddAccountMode,
-    });
-    if (outcome.kind === "callback") {
-      window.location.href = outcome.callbackUrl;
-      return;
-    }
-    setDesktopWaiting(false);
-    if (outcome.kind === "unavailable") setDesktopNotice(tDesktop("browser_unavailable"));
-    else if (outcome.kind === "declined") setDesktopNotice(tDesktop("server_declined"));
-    else if (outcome.kind === "failed") setDesktopNotice(tDesktop("browser_failed"));
   };
 
   const handleSubmit = async (e: React.FormEvent) => {
@@ -1858,7 +1862,7 @@ function LoginPageContent() {
                   </>
                 )}
 
-                {IS_DESKTOP_BUILD && !hasServerList && browserSignInAvailable() && (
+                {process.env.NEXT_PUBLIC_BULWARK_DESKTOP === "1" && !hasServerList && browserSignInAvailable() && (
                   <Button
                     type="button"
                     variant="outline"
diff --git a/app/api/auth/totp-token-exchange/route.ts b/app/api/auth/totp-token-exchange/route.ts
index 46e77ac33..a16be7089 100644
--- a/app/api/auth/totp-token-exchange/route.ts
+++ b/app/api/auth/totp-token-exchange/route.ts
@@ -173,7 +173,8 @@ export async function POST(request: NextRequest) {
       resolvedServerId = matchedEntry.id;
     } else if (configuredServerUrl && !customRequested) {
       upstreamUrl = configuredServerUrl;
-    } else if (IS_DESKTOP_BUILD && isDesktopTrustedServer(serverUrl)) {
+    // Spelled out as in lib/admin/jmap-servers.ts, so other builds don't hold it.
+    } else if (process.env.NEXT_PUBLIC_BULWARK_DESKTOP === '1' && isDesktopTrustedServer(serverUrl)) {
       upstreamUrl = serverUrl;
     } else if (allowCustomEndpoint) {
       if (!(await isPublicHttpUrl(serverUrl))) {
diff --git a/lib/__tests__/standalone-guard.test.ts b/lib/__tests__/standalone-guard.test.ts
index f982ecb14..7eac020df 100644
--- a/lib/__tests__/standalone-guard.test.ts
+++ b/lib/__tests__/standalone-guard.test.ts
@@ -39,6 +39,13 @@ describe('the desktop trust path', () => {
     expect(guardStandalone(dir, { desktopBuild: false })).toEqual(['.next/server/chunks/123.js (desktop trust path in a server build)']);
   });
 
+  it('fails a server build that still reads the flag at runtime', () => {
+    const dir = tempDir();
+    put(dir, 'server.js');
+    put(dir, '.next/server/chunks/9.js', 'let a="1"===process.env.NEXT_PUBLIC_BULWARK_DESKTOP');
+    expect(guardStandalone(dir, { desktopBuild: false })).toHaveLength(1);
+  });
+
   it('passes the desktop build itself', () => {
     const dir = tempDir();
     put(dir, 'server.js');
diff --git a/lib/admin/jmap-servers.ts b/lib/admin/jmap-servers.ts
index fa054875a..5bff4f136 100644
--- a/lib/admin/jmap-servers.ts
+++ b/lib/admin/jmap-servers.ts
@@ -1,7 +1,6 @@
 /**
  * Multi-server JMAP support: schema, parsing, lookup, and redaction helpers.
  */
-import { IS_DESKTOP_BUILD } from '@/lib/desktop/flag';
 import { isDesktopTrustedServer } from '@/lib/desktop/trusted-servers';
 
 
@@ -226,9 +225,10 @@ export function resolveTrustedJmapUrl(
   }
   const matched = servers.find((s) => normalizeUrl(s.url) === target);
   if (matched) return matched.url;
-  // A server the user approved in the desktop app. Compiled out of every other
-  // build, so nothing at runtime can open this path on a server.
-  if (IS_DESKTOP_BUILD && isDesktopTrustedServer(requestedUrl)) return trimUrl(requestedUrl);
+  // A server the user approved in the desktop app. Spelled out, not IS_DESKTOP_BUILD:
+  // only this form lets the bundler drop the branch and the module behind it, so
+  // that no other build holds this path at all (scripts/standalone-guard.mjs checks).
+  if (process.env.NEXT_PUBLIC_BULWARK_DESKTOP === '1' && isDesktopTrustedServer(requestedUrl)) return trimUrl(requestedUrl);
   // No match - caller decides whether to honor the request anyway (e.g. when
   // allowCustomJmapEndpoint is enabled).
   return null;
diff --git a/lib/desktop/__tests__/trust-flag.test.ts b/lib/desktop/__tests__/trust-flag.test.ts
index 202a4b1ff..a5534ff90 100644
--- a/lib/desktop/__tests__/trust-flag.test.ts
+++ b/lib/desktop/__tests__/trust-flag.test.ts
@@ -104,6 +104,14 @@ describe('the flag is fixed at build time', () => {
     expect(source).toContain("process.env.NEXT_PUBLIC_BULWARK_DESKTOP === '1'");
   });
 
+  it('the trust check uses the form the bundler can drop', () => {
+    for (const file of ['lib/admin/jmap-servers.ts', 'app/api/auth/totp-token-exchange/route.ts']) {
+      const source = readFileSync(path.join(ROOT, file), 'utf8');
+      expect(source, file).toMatch(/process\.env\.NEXT_PUBLIC_BULWARK_DESKTOP === '1' && isDesktopTrustedServer/);
+      expect(source, file).not.toMatch(/IS_DESKTOP_BUILD && isDesktopTrustedServer/);
+    }
+  });
+
   it('no image build sets it', () => {
     for (const file of ['Dockerfile', 'Dockerfile.lite']) {
       expect(readFileSync(path.join(ROOT, file), 'utf8')).not.toContain('NEXT_PUBLIC_BULWARK_DESKTOP');
diff --git a/lib/desktop/types.ts b/lib/desktop/types.ts
index 7ae919aa6..e2fefb496 100644
--- a/lib/desktop/types.ts
+++ b/lib/desktop/types.ts
@@ -92,9 +92,10 @@ export type DesktopPluginInstallResult =
 export interface DesktopPluginsBridge {
   /**
    * Installs from the directory through the local admin API, with its signature
-   * and hash checks. The renderer never holds an admin session. Standalone only.
+   * and hash checks, after a native prompt. No version means the latest. The
+   * renderer never holds an admin session. Standalone only.
    */
-  install: (slug: string, version: string) => Promise<DesktopPluginInstallResult>;
+  install: (slug: string, version?: string) => Promise<DesktopPluginInstallResult>;
 }
 
 export interface BulwarkDesktopBridge {
diff --git a/scripts/desktop-build-flag.mjs b/scripts/desktop-build-flag.mjs
index a6f52d122..8f9620507 100644
--- a/scripts/desktop-build-flag.mjs
+++ b/scripts/desktop-build-flag.mjs
@@ -7,6 +7,9 @@
 /** The marker scripts/standalone-guard.mjs looks for in a non-desktop build. */
 export const DESKTOP_TRUST_MARKER = 'bulwark.desktop.trustedJmapOrigins';
 
+/** A read of the flag that survived compiling: then setting it at runtime would work. */
+export const DESKTOP_FLAG_READ = 'NEXT_PUBLIC_BULWARK_DESKTOP';
+
 export function desktopBuildFlag(env = process.env) {
   return env.NEXT_PUBLIC_BULWARK_DESKTOP === '1' ? '1' : '';
 }
diff --git a/scripts/standalone-guard.mjs b/scripts/standalone-guard.mjs
index d44165b9e..b90081e7a 100644
--- a/scripts/standalone-guard.mjs
+++ b/scripts/standalone-guard.mjs
@@ -18,7 +18,7 @@
 import { existsSync, readdirSync, readFileSync, renameSync, rmSync, writeFileSync } from 'node:fs';
 import path from 'node:path';
 import { pathToFileURL } from 'node:url';
-import { DESKTOP_TRUST_MARKER, desktopBuildFlag } from './desktop-build-flag.mjs';
+import { DESKTOP_FLAG_READ, DESKTOP_TRUST_MARKER, desktopBuildFlag } from './desktop-build-flag.mjs';
 
 /** Top-level project entries the running server needs. Traces drop the rest. */
 const TRACE_ALLOWED = new Set(['node_modules', '.next', 'public', 'locales', 'package.json', 'VERSION']);
@@ -154,8 +154,11 @@ export function findDesktopTrustPath(standaloneDir) {
       const full = path.join(dir, entry.name);
       if (entry.isDirectory()) {
         if (entry.name !== 'node_modules') visit(full);
-      } else if (entry.name.endsWith('.js') && readFileSync(full, 'utf8').includes(DESKTOP_TRUST_MARKER)) {
-        found.push(`${toPosix(path.relative(standaloneDir, full))} (desktop trust path in a server build)`);
+      } else if (entry.name.endsWith('.js')) {
+        const text = readFileSync(full, 'utf8');
+        if (text.includes(DESKTOP_TRUST_MARKER) || text.includes(DESKTOP_FLAG_READ)) {
+          found.push(`${toPosix(path.relative(standaloneDir, full))} (desktop trust path in a server build)`);
+        }
       }
     }
   };