diff --git a/scripts/build-desktop-artifact.test.ts b/scripts/build-desktop-artifact.test.ts
index 50b86cfa3b4..0ac06a72e10 100644
--- a/scripts/build-desktop-artifact.test.ts
+++ b/scripts/build-desktop-artifact.test.ts
@@ -548,7 +548,7 @@ it.layer(NodeServices.layer)("build-desktop-artifact", (it) => {
     assert.notInclude(error.message, secret);
   });
 
-  it.effect("adds passkey entitlements and both renderer protocols to signed macOS builds", () =>
+  it.effect("adds passkey entitlements and the external protocol to signed macOS builds", () =>
     Effect.gen(function* () {
       const config = yield* createBuildConfig("mac", "dmg", "1.2.3", true, false, undefined, {
         entitlementsPath: "/tmp/entitlements.mac.plist",
@@ -559,9 +559,30 @@ it.layer(NodeServices.layer)("build-desktop-artifact", (it) => {
       assert.equal(config.appId, "com.t3tools.t3code");
       assert.equal(mac.entitlements, "/tmp/entitlements.mac.plist");
       assert.equal(mac.provisioningProfile, "/tmp/t3code.provisionprofile");
-      assert.deepStrictEqual(mac.protocols, [
-        { name: "T3 Code", schemes: ["t3code", "t3code-dev"] },
-      ]);
+      assert.deepStrictEqual(config.protocols, [{ name: "T3 Code", schemes: ["t3code"] }]);
+      assert.notProperty(mac, "protocols");
+    }).pipe(Effect.provide(ConfigProvider.layer(ConfigProvider.fromEnv({ env: {} })))),
+  );
+
+  it.effect("declares the external protocol for Linux desktop integration", () =>
+    Effect.gen(function* () {
+      const config = yield* createBuildConfig(
+        "linux",
+        "AppImage",
+        "1.2.3",
+        false,
+        false,
+        undefined,
+        undefined,
+      );
+
+      const linux = config.linux as Record<string, unknown>;
+      assert.deepStrictEqual(config.protocols, [{ name: "T3 Code", schemes: ["t3code"] }]);
+      assert.notProperty(linux, "protocols");
+      assert.notProperty(
+        (linux.desktop as { readonly entry: Record<string, unknown> }).entry,
+        "MimeType",
+      );
     }).pipe(Effect.provide(ConfigProvider.layer(ConfigProvider.fromEnv({ env: {} })))),
   );
 
@@ -578,6 +599,7 @@ it.layer(NodeServices.layer)("build-desktop-artifact", (it) => {
       );
 
       const win = config.win as Record<string, unknown>;
+      assert.deepStrictEqual(config.protocols, [{ name: "T3 Code", schemes: ["t3code"] }]);
       assert.equal(win.icon, "icon.ico");
       assert.equal(win.signAndEditExecutable, true);
       assert.notProperty(win, "azureSignOptions");
diff --git a/scripts/build-desktop-artifact.ts b/scripts/build-desktop-artifact.ts
index 2f530eec29a..3f53471093e 100644
--- a/scripts/build-desktop-artifact.ts
+++ b/scripts/build-desktop-artifact.ts
@@ -1573,6 +1573,15 @@ export const createBuildConfig = Effect.fn("createBuildConfig")(function* (
     artifactName: "T3-Code-${version}-${arch}.${ext}",
     electronLanguages: [...DESKTOP_ELECTRON_LANGUAGES],
     files: [...DESKTOP_FILE_EXCLUSIONS],
+    // electron-builder writes this into macOS CFBundleURLTypes and Linux
+    // x-scheme-handler metadata. Windows NSIS builds register the same scheme
+    // at runtime through app.setAsDefaultProtocolClient.
+    protocols: [
+      {
+        name: "T3 Code",
+        schemes: ["t3code"],
+      },
+    ],
     directories: {
       buildResources: "apps/desktop/resources",
     },
@@ -1600,12 +1609,6 @@ export const createBuildConfig = Effect.fn("createBuildConfig")(function* (
       target: target === "dmg" ? [target, "zip"] : [target],
       icon: "icon.icns",
       category: "public.app-category.developer-tools",
-      protocols: [
-        {
-          name: "T3 Code",
-          schemes: ["t3code", "t3code-dev"],
-        },
-      ],
       ...(macPasskeySigning
         ? {
             entitlements: macPasskeySigning.entitlementsPath,
@@ -1624,17 +1627,8 @@ export const createBuildConfig = Effect.fn("createBuildConfig")(function* (
       desktop: {
         entry: {
           StartupWMClass: "t3code",
-          // Register the external deep-link scheme so xdg-open can launch T3.
-          // electron-builder keeps %U on Exec when MimeType is present.
-          MimeType: "x-scheme-handler/t3code;",
         },
       },
-      protocols: [
-        {
-          name: "T3 Code",
-          schemes: ["t3code"],
-        },
-      ],
     };
   }