diff --git a/.env.example b/.env.example
index 3905dc2c8f..cb1f6860d2 100644
--- a/.env.example
+++ b/.env.example
@@ -26,7 +26,8 @@ BUZZ_DEV_VIEWER=
 
 # Optional public Builderlab URL, exposed as import.meta.env.VITE_BUZZ_BUILDERLAB_URL.
 # Read by Vite from .env.local or the build process environment (process wins,
-# including empty). Unset means empty; no deployment URL is supplied by the repo.
+# including empty). Defaults to https://app.builderlab.xyz; set an empty value
+# to disable Builderlab sign-in and the bundled plugin's native grants.
 # Packaging embeds the value; changing the launched app's environment has no effect.
 # Restart Vite for development changes; rebuild/repackage for distributed apps.
 # BUZZ_BUILDERLAB_URL=https://builderlab.example.com
diff --git a/browser-host/vite-config.test.mjs b/browser-host/vite-config.test.mjs
index 78406b929e..5f5f1e45ba 100644
--- a/browser-host/vite-config.test.mjs
+++ b/browser-host/vite-config.test.mjs
@@ -139,6 +139,21 @@ it("loads the broker's Vite config without native-compatibility warnings", () =>
               );
             }
             delete process.env.BUZZ_DATABRICKS_HOST;
+            // A fresh checkout uses production for both dev and packaged frontends.
+            // Explicit empty values retain the deployment opt-out.
+            for (const local of ['', 'BUZZ_BUILDERLAB_URL=']) {
+              writeFileSync('.env.local', local);
+              delete process.env.BUZZ_BUILDERLAB_URL;
+              for (const command of ['serve', 'build']) {
+                const result = await loadConfigFromFile(
+                  { command, mode: command === 'serve' ? 'development' : 'production' }, configFile,
+                );
+                assert.equal(
+                  result.config.define['import.meta.env.VITE_BUZZ_BUILDERLAB_URL'],
+                  JSON.stringify(local ? '' : 'https://app.builderlab.xyz'),
+                );
+              }
+            }
             // Desktop shares .env.local/process inputs with the native build.
             // An explicit empty process value clears the frontend URL too.
             writeFileSync('.env.local', 'BUZZ_BUILDERLAB_URL=https://app.builderlab.xyz/');
diff --git a/crates/plugin-manager/build.rs b/crates/plugin-manager/build.rs
index 73647367d8..e5902ec728 100644
--- a/crates/plugin-manager/build.rs
+++ b/crates/plugin-manager/build.rs
@@ -10,7 +10,7 @@ fn builderlab_origin(local: &Path, process: Option<String>) -> Result<String, &'
     let raw = values
         .get(BUILDERLAB_URL_KEY)
         .map(String::as_str)
-        .unwrap_or("");
+        .unwrap_or("https://app.builderlab.xyz");
     if raw.is_empty() {
         return Ok(String::new());
     }
@@ -51,18 +51,30 @@ mod tests {
     use super::*;
 
     #[test]
-    fn local_url_and_process_overrides_produce_an_exact_origin() {
+    fn defaults_to_production_unless_explicitly_disabled() {
         let directory = tempfile::tempdir().unwrap();
         let local = directory.path().join(".env.local");
+        assert_eq!(
+            builderlab_origin(&local, None).unwrap(),
+            "https://app.builderlab.xyz"
+        );
+        assert_eq!(builderlab_origin(&local, Some(String::new())).unwrap(), "");
+        std::fs::write(&local, "BUZZ_BUILDERLAB_URL=\n").unwrap();
         assert_eq!(builderlab_origin(&local, None).unwrap(), "");
+    }
+
+    #[test]
+    fn local_url_and_process_overrides_produce_an_exact_origin() {
+        let directory = tempfile::tempdir().unwrap();
+        let local = directory.path().join(".env.local");
         std::fs::write(
             &local,
-            "\u{feff}export BUZZ_BUILDERLAB_URL=\"https://APP.BUILDERLAB.XYZ:443/deployment/\" # comment\n",
+            "\u{feff}export BUZZ_BUILDERLAB_URL=\"https://OVERRIDE.EXAMPLE:443/deployment/\" # comment\n",
         )
         .unwrap();
         assert_eq!(
             builderlab_origin(&local, None).unwrap(),
-            "https://app.builderlab.xyz"
+            "https://override.example"
         );
         assert_eq!(
             builderlab_origin(&local, Some("https://login.example:8443/path/".into())).unwrap(),
@@ -99,19 +111,22 @@ mod tests {
         let directory = tempfile::tempdir().unwrap();
         let local = directory.path().join(".env.local");
         std::fs::write(&local, "PRIVATE_VALUE='unterminated").unwrap();
-        assert_eq!(builderlab_origin(&local, None).unwrap(), "");
+        assert_eq!(
+            builderlab_origin(&local, None).unwrap(),
+            "https://app.builderlab.xyz"
+        );
 
         for quote in ["'", "\"", "`"] {
             std::fs::write(
                 &local,
                 format!(
-                    "PRIVATE_VALUE={quote}multiline\nBUZZ_BUILDERLAB_URL=https://hidden.example\n{quote}\nINVALID=unquoted value\nexport BUZZ_BUILDERLAB_URL=https://app.builderlab.xyz/\nTRAILING='unfinished\n"
+                    "PRIVATE_VALUE={quote}multiline\nBUZZ_BUILDERLAB_URL=https://hidden.example\n{quote}\nINVALID=unquoted value\nexport BUZZ_BUILDERLAB_URL=https://after-multiline.example/\nTRAILING='unfinished\n"
                 ),
             )
             .unwrap();
             assert_eq!(
                 builderlab_origin(&local, None).unwrap(),
-                "https://app.builderlab.xyz"
+                "https://after-multiline.example"
             );
         }
         for quote in ["'", "\""] {
@@ -122,7 +137,10 @@ mod tests {
                 ),
             )
             .unwrap();
-            assert_eq!(builderlab_origin(&local, None).unwrap(), "");
+            assert_eq!(
+                builderlab_origin(&local, None).unwrap(),
+                "https://app.builderlab.xyz"
+            );
         }
     }
 }
diff --git a/docs/configuration.md b/docs/configuration.md
index f212a03e97..b2d9308f69 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -1,14 +1,14 @@
 # Deployment configuration: current-feature parity
 
 Buzz Foundation supports configuration for capabilities that exist here, not a
-port of every OG Buzz feature. Keep deployment values in local/CI configuration,
-not in source. Build defaults are readable binary data, **never secret storage**.
+port of every OG Buzz feature. Keep deployment overrides in local/CI configuration.
+Build defaults are readable binary data, **never secret storage**.
 
 ## Supported inputs and surfaces
 
 | Input | Consumer and boundary |
 | --- | --- |
-| `BUZZ_BUILDERLAB_URL` | Shared frontend/native build: public login URL and the bundled plugin's exact HTTPS host grant; no runtime override. |
+| `BUZZ_BUILDERLAB_URL` | Shared frontend/native build: public login URL and the bundled plugin's native grants; no runtime override. |
 | `BUZZ_DEFAULT_COMMUNITY_URL` | Packaged frontend build: secure relay origin to select once, after identity setup, only when this viewer has no saved community record. Saved choices, including Personal space, always win. Unset in OSS builds. |
 | `BUZZ_DATABRICKS_HOST` | Frontend build and dev server: `https://` Databricks workspace URL passed as `DATABRICKS_HOST` to every bundled `goose-acp`, which then prefers it to the host in goose's config. Unset in OSS builds. See [Databricks host](#databricks-host). |
 | `BUZZ_RELAY_URL` | Live development broker's default community, not an agent relay override or a packaged default. |
@@ -67,8 +67,10 @@ builds.
 
 ## Builderlab URL build input
 
-Set `BUZZ_BUILDERLAB_URL` in repository-root `.env.local` for development, or in
-the process running `bin/pnpm build` / `bin/pnpm tauri build` for packaging:
+Development and packaged builds default to `https://app.builderlab.xyz`, matching
+the desktop release workflow. To use another deployment, set `BUZZ_BUILDERLAB_URL`
+in repository-root `.env.local` for development, or in the process running
+`bin/pnpm build` / `bin/pnpm tauri build` for packaging:
 
 ```sh
 BUZZ_BUILDERLAB_URL=https://app.builderlab.xyz bin/pnpm tauri build
@@ -79,14 +81,23 @@ repository-root `.env.local` and process values using the native dotenv pattern.
 For desktop, supply the full URL in `.env.local` or the build process environment
 so both stages receive it. Vite's additional `.env` and mode-specific files do
 not configure native grants. Process values take precedence, including an
-explicit empty value. When unset or empty, login is unconfigured and no network
-origin is granted. Local builds have no deployment default. The desktop release
-workflow supplies the production URL by default; see [release configuration](releases.md#builderlab-url).
+explicit empty value. Set `BUZZ_BUILDERLAB_URL=` to leave login unconfigured and
+clear the bundled plugin's native grants. The desktop release workflow supplies the
+production URL by default; see [release configuration](releases.md#builderlab-url).
 
 Any HTTPS host is supported, including an explicit port or deployment path. URL
 credentials, query parameters and fragments are rejected by the native build.
 The desktop's native plugin catalog supplies the effective manifest, granting
-only the configured URL's exact origin. Never put credentials in this input.
+the configured URL's exact origin. For recognized Builderlab deployments, its
+existing Apps policy also grants file access and the mapped control-plane origin
+(`https://compose-ctrl.builderlab.xyz` for production). Never put credentials in
+this input.
+
+The build origin also controls whether a Builderlab session can be reused by
+identity backup when its separately configured service URL has the same origin.
+Backup still requires its own service URL, namespace and user choice. The existing
+identity-binding validator accepts production Builderlab or the configured origin;
+production binding was already allowed before this default.
 
 The bundled Builderlab login consumes this public URL and appends `/api/goose`.
 
diff --git a/src/bundled/reminders/RemindDialog.test.tsx b/src/bundled/reminders/RemindDialog.test.tsx
index 04fe60c25b..e758c71e74 100644
--- a/src/bundled/reminders/RemindDialog.test.tsx
+++ b/src/bundled/reminders/RemindDialog.test.tsx
@@ -190,6 +190,9 @@ it("reveals labelled custom fields and saves a future time with the note", async
   screen.getByRole("combobox", { name: "When" }).focus();
   await user.keyboard("{Enter}");
   await screen.findByRole("option", { name: "Custom date & time" });
+  await vi.waitFor(() =>
+    expect(screen.getByRole("option", { selected: true })).toHaveFocus(),
+  );
   await user.keyboard("{End}{Enter}");
   fireEvent.change(screen.getByLabelText("Reminder date"), {
     target: { value: "" },
diff --git a/vite.config.ts b/vite.config.ts
index a0b36b7e01..872901c8cd 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -86,7 +86,7 @@ export default defineConfig(async ({ command, mode }) => {
       ),
       "import.meta.env.VITE_BUZZ_COMMUNITY_ALIASES": JSON.stringify(aliases),
       "import.meta.env.VITE_BUZZ_BUILDERLAB_URL": JSON.stringify(
-        env.BUZZ_BUILDERLAB_URL ?? "",
+        env.BUZZ_BUILDERLAB_URL ?? "https://app.builderlab.xyz",
       ),
       "import.meta.env.VITE_BUZZ_OPEN_RELAY": JSON.stringify(openOrigin),
       "import.meta.env.VITE_BUZZ_DATABRICKS_HOST":