diff --git a/apps/desktop/src/shell/DesktopShellEnvironment.test.ts b/apps/desktop/src/shell/DesktopShellEnvironment.test.ts
index 79344567fcd6c..b5bde775927f3 100644
--- a/apps/desktop/src/shell/DesktopShellEnvironment.test.ts
+++ b/apps/desktop/src/shell/DesktopShellEnvironment.test.ts
@@ -4,6 +4,7 @@ import { assert, describe, it } from "@effect/vitest";
 import * as HostProcess from "@t3tools/shared/HostProcess";
 import * as Effect from "effect/Effect";
 import * as Deferred from "effect/Deferred";
+import * as Fiber from "effect/Fiber";
 import * as FileSystem from "effect/FileSystem";
 import * as Layer from "effect/Layer";
 import * as Logger from "effect/Logger";
@@ -164,6 +165,10 @@ describe("DesktopShellEnvironment", () => {
             const startup = yield* service.installIntoProcess.pipe(Effect.forkChild);
             yield* Deferred.await(started);
             assert.isDefined(startup.pollUnsafe());
+            assert.isFalse(
+              yield* Fiber.join(startup),
+              "nothing was installed yet, so the server must hydrate PATH itself",
+            );
             yield* Deferred.succeed(release, undefined);
             return yield* service.awaitDiscovery;
           }),
@@ -231,7 +236,7 @@ describe("DesktopShellEnvironment", () => {
           }),
           use: (service) =>
             Effect.gen(function* () {
-              yield* service.installIntoProcess;
+              assert.isTrue(yield* service.installIntoProcess);
               yield* service.installIntoProcess;
               assert.equal(env.PATH, "/old/bin:/usr/bin:/launcher/bin");
               assert.equal(env.SSH_AUTH_SOCK, "/current-session.sock");
diff --git a/apps/desktop/src/shell/DesktopShellEnvironment.ts b/apps/desktop/src/shell/DesktopShellEnvironment.ts
index 556f7090b422e..dff70213ca74d 100644
--- a/apps/desktop/src/shell/DesktopShellEnvironment.ts
+++ b/apps/desktop/src/shell/DesktopShellEnvironment.ts
@@ -75,7 +75,8 @@ export class DesktopShellEnvironmentCommandTimeoutError extends Schema.TaggedErr
 export class DesktopShellEnvironment extends Context.Service<
   DesktopShellEnvironment,
   {
-    // Desktop owns discovery, including on cache misses; the backend receives updates over fd4.
+    // Yields true only when a cached environment was applied; on a miss the backend hydrates
+    // PATH itself until desktop discovery arrives over fd4.
     readonly installIntoProcess: Effect.Effect<boolean>;
     readonly awaitDiscovery: Effect.Effect<boolean>;
     readonly updates: Stream.Stream<DesktopShellEnvironmentSnapshot>;
@@ -622,7 +623,8 @@ export const make = Effect.gen(function* () {
       const cache = yield* fileSystem
         .readFileString(cachePath)
         .pipe(Effect.flatMap(decodeCache), Effect.option);
-      if (Option.isSome(cache) && cache.value.key === key) {
+      const hit = Option.isSome(cache) && cache.value.key === key;
+      if (hit) {
         const cached = Object.fromEntries(
           CACHED_ENV_NAMES.flatMap((name) => {
             const value = cache.value.environment[name];
@@ -648,7 +650,7 @@ export const make = Effect.gen(function* () {
         );
       }
       yield* Effect.forkIn(refresh, scope);
-      return true;
+      return hit;
     }).pipe(Effect.withSpan("desktop.shellEnvironment.installIntoProcess")),
   );
   const updates = Stream.unwrap(