OpenKnots · BunsDev · Apr 13, 2026 · Apr 13, 2026
diff --git a/apps/web/src/appSettings.test.ts b/apps/web/src/appSettings.test.ts
@@ -3,11 +3,13 @@ import { describe, expect, it } from "vitest";
 
 import {
   AppSettingsSchema,
+  DEFAULT_BROWSER_PREVIEW_START_PAGE_URL,
   DEFAULT_PR_REVIEW_REQUEST_CHANGES_TONE,
   DEFAULT_SIDEBAR_FONT_SIZE,
   DEFAULT_SIDEBAR_PROJECT_ROW_HEIGHT,
   DEFAULT_SIDEBAR_SPACING,
   DEFAULT_SIDEBAR_THREAD_ROW_HEIGHT,
+  resolveBrowserPreviewStartPageUrl,
 } from "./appSettings";
 
 describe("AppSettingsSchema", () => {
@@ -22,6 +24,7 @@ describe("AppSettingsSchema", () => {
 
     expect(settings.showNotificationDetails).toBe(false);
     expect(settings.includeDiagnosticsTipsInCopy).toBe(false);
+    expect(settings.browserPreviewStartPageUrl).toBe("");
   });
 
   it("defaults sidebar appearance controls", () => {
@@ -57,3 +60,19 @@ describe("AppSettingsSchema", () => {
     expect(settings.prReviewRequestChangesTone).toBe(DEFAULT_PR_REVIEW_REQUEST_CHANGES_TONE);
   });
 });
+
+describe("resolveBrowserPreviewStartPageUrl", () => {
+  it("falls back to the default start page for blank or invalid values", () => {
+    expect(resolveBrowserPreviewStartPageUrl("")).toBe(DEFAULT_BROWSER_PREVIEW_START_PAGE_URL);
+    expect(resolveBrowserPreviewStartPageUrl("not-a-url")).toBe(
+      DEFAULT_BROWSER_PREVIEW_START_PAGE_URL,
+    );
+  });
+
+  it("normalizes valid http and https URLs", () => {
+    expect(resolveBrowserPreviewStartPageUrl(" https://example.com ")).toBe("https://example.com/");
+    expect(resolveBrowserPreviewStartPageUrl("http://localhost:3000/path")).toBe(
+      "http://localhost:3000/path",
+    );
+  });
+});
diff --git a/apps/web/src/appSettings.ts b/apps/web/src/appSettings.ts
@@ -11,6 +11,7 @@ import {
   normalizeModelSlug,
   resolveSelectableModel,
 } from "@okcode/shared/model";
+import { validateHttpPreviewUrl } from "@okcode/shared/preview";
 import { APP_LOCALE_PREFERENCES } from "./i18n/types";
 import { useLocalStorage } from "./hooks/useLocalStorage";
 import { EnvMode } from "./components/BranchToolbar.logic";
@@ -32,6 +33,7 @@ export const DEFAULT_SIDEBAR_FONT_SIZE = 12;
 export const SIDEBAR_SPACING_MIN = 4;
 export const SIDEBAR_SPACING_MAX = 12;
 export const DEFAULT_SIDEBAR_SPACING = 8;
+export const DEFAULT_BROWSER_PREVIEW_START_PAGE_URL = "https://www.google.com/";
 
 export const TimestampFormat = Schema.Literals(["locale", "12-hour", "24-hour"]);
 export type TimestampFormat = typeof TimestampFormat.Type;
@@ -96,6 +98,9 @@ export const AppSettingsSchema = Schema.Struct({
   includeDiagnosticsTipsInCopy: Schema.Boolean.pipe(withDefaults(() => false)),
   locale: AppLocale.pipe(withDefaults(() => DEFAULT_APP_LOCALE)),
   openLinksExternally: Schema.Boolean.pipe(withDefaults(() => false)),
+  browserPreviewStartPageUrl: Schema.String.check(Schema.isMaxLength(4096)).pipe(
+    withDefaults(() => ""),
+  ),
   sidebarProjectSortOrder: SidebarProjectSortOrder.pipe(
     withDefaults(() => DEFAULT_SIDEBAR_PROJECT_SORT_ORDER),
   ),
@@ -227,6 +232,7 @@ function normalizeAppSettings(settings: AppSettings): AppSettings {
   return {
     ...settings,
     backgroundImageUrl: settings.backgroundImageUrl.trim(),
+    browserPreviewStartPageUrl: settings.browserPreviewStartPageUrl.trim(),
     backgroundImageOpacity: clampBackgroundOpacity(settings.backgroundImageOpacity),
     sidebarOpacity: clampOpacity(settings.sidebarOpacity),
     sidebarProjectRowHeight: clampSidebarProjectRowHeight(settings.sidebarProjectRowHeight),
@@ -377,6 +383,16 @@ export function getProviderStartOptions(
   return Object.keys(providerOptions).length > 0 ? providerOptions : undefined;
 }
 
+export function resolveBrowserPreviewStartPageUrl(rawUrl: string | null | undefined): string {
+  const trimmedUrl = rawUrl?.trim() ?? "";
+  if (trimmedUrl.length === 0) {
+    return DEFAULT_BROWSER_PREVIEW_START_PAGE_URL;
+  }
+
+  const validatedUrl = validateHttpPreviewUrl(trimmedUrl);
+  return validatedUrl.ok ? validatedUrl.url : DEFAULT_BROWSER_PREVIEW_START_PAGE_URL;
+}
+
 export function useAppSettings() {
   const [settings, setSettings] = useLocalStorage(
     APP_SETTINGS_STORAGE_KEY,

diff --git a/apps/web/src/components/PreviewPanel.tsx b/apps/web/src/components/PreviewPanel.tsx
@@ -24,6 +24,7 @@ import {
 } from "lucide-react";
 
 import { validateHttpPreviewUrl } from "@okcode/shared/preview";
+import { resolveBrowserPreviewStartPageUrl, useAppSettings } from "~/appSettings";
 import { readDesktopPreviewBridge } from "~/desktopPreview";
 import {
   type BrowserPresetId,
@@ -145,6 +146,7 @@ function resolveViewportDimensions(
 }
 
 export function PreviewPanel({ projectId, threadId, onClose }: PreviewPanelProps) {
+  const { settings } = useAppSettings();
   const previewBridge = readDesktopPreviewBridge();
   const setProjectOpen = usePreviewStateStore((state) => state.setProjectOpen);
   const favoriteUrls = usePreviewStateStore((state) => state.favoriteUrls);
@@ -412,8 +414,10 @@ export function PreviewPanel({ projectId, threadId, onClose }: PreviewPanelProps
         return;
       }
     }
-    // Create tab with a default page
-    void previewBridge?.createTab({ url: "https://www.google.com", threadId });
+    void previewBridge?.createTab({
+      url: resolveBrowserPreviewStartPageUrl(settings.browserPreviewStartPageUrl),
+      threadId,
+    });
   };
 
   const onClosePreview = () => {

diff --git a/apps/web/src/routes/_chat.settings.tsx b/apps/web/src/routes/_chat.settings.tsx
@@ -34,7 +34,9 @@ import {
   DEFAULT_GIT_TEXT_GENERATION_MODEL,
 } from "@okcode/contracts";
 import { getModelOptions, normalizeModelSlug } from "@okcode/shared/model";
+import { validateHttpPreviewUrl } from "@okcode/shared/preview";
 import {
+  DEFAULT_BROWSER_PREVIEW_START_PAGE_URL,
   DEFAULT_SIDEBAR_FONT_SIZE,
   DEFAULT_SIDEBAR_PROJECT_ROW_HEIGHT,
   DEFAULT_SIDEBAR_SPACING,
@@ -46,6 +48,7 @@ import {
   MODEL_PROVIDER_SETTINGS,
   patchCustomModels,
   PrReviewRequestChangesTone,
+  resolveBrowserPreviewStartPageUrl,
   SIDEBAR_FONT_SIZE_MAX,
   SIDEBAR_FONT_SIZE_MIN,
   SIDEBAR_PROJECT_ROW_HEIGHT_MAX,
@@ -758,6 +761,14 @@ function SettingsRouteView() {
   const { settings, defaults, updateSettings, resetSettings } = useAppSettings();
   const serverConfigQuery = useQuery(serverConfigQueryOptions());
   const queryClient = useQueryClient();
+  const trimmedBrowserPreviewStartPageUrl = settings.browserPreviewStartPageUrl.trim();
+  const browserPreviewStartPageValidation =
+    trimmedBrowserPreviewStartPageUrl.length > 0
+      ? validateHttpPreviewUrl(trimmedBrowserPreviewStartPageUrl)
+      : null;
+  const effectiveBrowserPreviewStartPageUrl = resolveBrowserPreviewStartPageUrl(
+    settings.browserPreviewStartPageUrl,
+  );
   const projects = useStore((state) => state.projects);
   const threads = useStore((state) => state.threads);
   const [selectedProjectId, setSelectedProjectId] = useState<ProjectId | null>(
@@ -2133,6 +2144,64 @@ function SettingsRouteView() {
                       }
                     />
 
+                    <SettingsRow
+                      title="Browser preview start page"
+                      description="Used when opening a new browser preview tab without typing a URL first."
+                      status={
+                        trimmedBrowserPreviewStartPageUrl.length === 0 ? (
+                          <>
+                            Blank uses the default start page:{" "}
+                            <code>{DEFAULT_BROWSER_PREVIEW_START_PAGE_URL}</code>
+                          </>
+                        ) : browserPreviewStartPageValidation?.ok ? (
+                          <>
+                            New blank preview tabs will open at{" "}
+                            <code>{browserPreviewStartPageValidation.url}</code>.
+                          </>
+                        ) : (
+                          <>
+                            <span className="text-destructive">
+                              Invalid URL. Falling back to{" "}
+                              <code>{DEFAULT_BROWSER_PREVIEW_START_PAGE_URL}</code>.
+                            </span>
+                            <span className="mt-1 block break-all">
+                              Effective start page:{" "}
+                              <code>{effectiveBrowserPreviewStartPageUrl}</code>
+                            </span>
+                          </>
+                        )
+                      }
+                      resetAction={
+                        settings.browserPreviewStartPageUrl !==
+                        defaults.browserPreviewStartPageUrl ? (
+                          <SettingResetButton
+                            label="browser preview start page"
+                            onClick={() =>
+                              updateSettings({
+                                browserPreviewStartPageUrl: defaults.browserPreviewStartPageUrl,
+                              })
+                            }
+                          />
+                        ) : null
+                      }
+                      control={
+                        <Input
+                          value={settings.browserPreviewStartPageUrl}
+                          onChange={(event) =>
+                            updateSettings({
+                              browserPreviewStartPageUrl: event.target.value,
+                            })
+                          }
+                          placeholder={DEFAULT_BROWSER_PREVIEW_START_PAGE_URL}
+                          aria-label="Browser preview start page"
+                          autoCapitalize="off"
+                          autoCorrect="off"
+                          spellCheck={false}
+                          className="w-full sm:w-72"
+                        />
+                      }
+                    />
+
                     <SettingsRow
                       title="Code Preview Autosave"
                       description="Automatically save edits made in the built-in code preview after a short delay."