diff --git a/apps/code/forge.config.ts b/apps/code/forge.config.ts
index af4ba91e7..e25896cb1 100644
--- a/apps/code/forge.config.ts
+++ b/apps/code/forge.config.ts
@@ -219,6 +219,12 @@ const config: ForgeConfig = {
         icon: "./build/app-icon.png",
         categories: ["Development"],
         bin: "PostHog Code",
+        // Declare the custom URL scheme handler in the generated .desktop file
+        // so desktop integration registers x-scheme-handler/posthog-code and
+        // OAuth callbacks (posthog-code://) can route back to the AppImage.
+        // The deb/rpm makers get this via sharedLinuxOptions; without it,
+        // AppImage users cannot complete login. See sharedLinuxOptions.mimeType.
+        mimeType: ["x-scheme-handler/posthog-code"],
       },
     }),
     new MakerDeb({
diff --git a/apps/code/src/main/platform-adapters/electron-app-lifecycle.ts b/apps/code/src/main/platform-adapters/electron-app-lifecycle.ts
index 94e645be5..be1bf2e97 100644
--- a/apps/code/src/main/platform-adapters/electron-app-lifecycle.ts
+++ b/apps/code/src/main/platform-adapters/electron-app-lifecycle.ts
@@ -29,6 +29,12 @@ export class ElectronAppLifecycle implements IAppLifecycle {
   }
 
   public registerDeepLinkScheme(scheme: string): void {
+    // NOTE: setAsDefaultProtocolClient's optional `path`/`args` are Windows-only
+    // and ignored on Linux/macOS. On Linux, registration relies on the packaged
+    // .desktop file declaring `MimeType=x-scheme-handler/<scheme>` so desktop
+    // integration can route the scheme — see forge.config.ts (the AppImage,
+    // deb, and rpm makers all set `mimeType`). Passing an AppImage exec path
+    // here would be a no-op, so it is intentionally omitted.
     app.setAsDefaultProtocolClient(scheme);
   }
 }