fix(preview): agents can close tabs their desktop browser tab opens

apps/server/src/preview/ServerBrowser.test.ts

@@ -3107,6 +3107,41 @@ it.live("failed session and browser launches release capacity, as does closing a
   ).pipe(Effect.provide(layer)),
 );
 
+it.live("a tab opened from an agent's tab joins that agent only while it has room", () =>
+  Effect.scoped(
+    Effect.gen(function* () {
+      const { browser, broker, tabId } = yield* ready;
+      const threadId = scope.thread.threadId;
+      const openFrom = (openerTabId: PreviewTabId) =>
+        browser.open({ threadId, url: "https://example.org/", runtime: "server", openerTabId });
+      const manager = yield* Manager.PreviewManager;
+      const { sessions } = yield* manager.list({ threadId });
+      const owner = sessions.find((session) => session.tabId === tabId)?.automationOwner;
+      const popup = yield* openFrom(tabId);
+      expect(popup.automationOwner).toBeDefined();
+      expect(popup.automationOwner).toBe(owner);
+      const status = yield* broker.invoke<PreviewAutomationStatus>({
+        scope,
+        tabId,
+        operation: "status",
+        input: {},
+      });
+      expect(status.tabs?.find((entry) => entry.tabId === popup.tabId)?.openerTabId).toBe(tabId);
+      const open = broker.invoke<PreviewAutomationStatus>({
+        scope,
+        operation: "open",
+        input: { reuseExistingTab: false, show: false },
+      });
+      for (let count = 2; count < 8; count++) yield* open;
+
+      const overflow = yield* openFrom(tabId);
+      expect(overflow.automationOwner).toBeUndefined();
+      yield* broker.invoke({ scope, tabId, operation: "close", input: {} });
+      expect((yield* open).available).toBe(true);
+    }),
+  ).pipe(Effect.provide(layer)),
+);
+
 it.live("a full server takes back the slot of the longest idle agent tab nobody views", () =>
   Effect.scoped(
     Effect.gen(function* () {

apps/server/src/preview/ServerBrowser.ts

@@ -39,8 +39,10 @@ import {
   type PreviewAutomationUploadInput,
   type PreviewAutomationWaitForInput,
   PreviewClearProfileError,
+  type PreviewError,
   type PreviewEvent,
   type PreviewNavStatus,
+  type PreviewOpenInput,
   type PreviewSessionSnapshot,
   type PreviewViewportSetting,
   ThreadId,
@@ -283,6 +285,9 @@ export class ServerBrowser extends Context.Service<
       readonly downloadId: string;
     }) => Effect.Effect<Option.Option<{ readonly path: string; readonly fileName: string }>>;
 
+    /** A tab opened from an agent's tab joins that agent while it has room for another. */
+    readonly open: (input: PreviewOpenInput) => Effect.Effect<PreviewSessionSnapshot, PreviewError>;
+
     readonly clearProfile: (profileId: string) => Effect.Effect<void, PreviewClearProfileError>;
 
     readonly profileReporter: Effect.Effect<ProfileReporter, never, Scope.Scope>;
@@ -535,6 +540,7 @@ const make = Effect.gen(function* () {
 
   const closedPendingTabs = new Set<string>();
   const adoptedPages = new Map<string, { readonly page: Page; readonly openerTabId: string }>();
+  const desktopOpeners = new Map<string, string>();
   const closedSessions = new Set<string>();
   let hostConnectionId: string | null = null;
   let viewerResizeOrder = 0;
@@ -895,6 +901,8 @@ const make = Effect.gen(function* () {
   ): Promise<ServerTab> => {
     const adopted = adoptedPages.get(tabKey(snapshot.threadId, snapshot.tabId));
     adoptedPages.delete(tabKey(snapshot.threadId, snapshot.tabId));
+    const desktopOpener = desktopOpeners.get(tabKey(snapshot.threadId, snapshot.tabId));
+    desktopOpeners.delete(tabKey(snapshot.threadId, snapshot.tabId));
     const desktop =
       adopted === undefined && (await desktopRenders(snapshot))
         ? await connectDesktop(snapshot)
@@ -965,7 +973,7 @@ const make = Effect.gen(function* () {
       isolatedContext,
       desktop: desktop === null ? null : { close: desktop.close },
       profileId: snapshot.profileId,
-      openerTabId: adopted?.openerTabId,
+      openerTabId: adopted?.openerTabId ?? desktopOpener,
       downloads: [],
       fileChooser: null,
       dialog: null,
@@ -3101,8 +3109,34 @@ const make = Effect.gen(function* () {
       catch: (cause) => new PreviewClearProfileError({ profileId, cause }),
     });
 
+  const open = Effect.fn("ServerBrowser.open")(function* (input: PreviewOpenInput) {
+    const { openerTabId, ...openInput } = input;
+    const owner =
+      openerTabId === undefined || input.runtime !== "server"
+        ? undefined
+        : (yield* manager.list({ threadId: input.threadId })).sessions.find(
+            (session) => session.tabId === openerTabId,
+          )?.automationOwner;
+    if (owner === undefined || openerTabId === undefined || atTabLimit(owner))
+      return yield* manager.open(openInput);
+    let opened: PreviewSessionSnapshot | undefined;
+    return yield* openTab({
+      ...openInput,
+      automationOwner: owner,
+      beforePublish: (snapshot) => {
+        opened = snapshot;
+        desktopOpeners.set(tabKey(snapshot.threadId, snapshot.tabId), openerTabId);
+      },
+    }).pipe(
+      Effect.flatMap(() => (opened ? Effect.succeed(opened) : Effect.fail(undefined))),
+      // Losing a capacity race or the launch still opens the tab the user clicked, unclaimed.
+      Effect.catch(() => manager.open(openInput)),
+    );
+  });
+
   return ServerBrowser.of({
     attachViewer,
+    open,
     clearProfile,
     profileReporter,
     openDownload,

apps/server/src/preview/ServerBrowserStream.test.ts

@@ -88,6 +88,7 @@ it.effect.each([
     });
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: () => Effect.succeedNone,
       answerFileChooser: () => Effect.succeed(false),
@@ -163,6 +164,7 @@ it.effect("sends replies ahead of stale frames and only the newest frame after a
     });
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: () => Effect.succeedNone,
       answerFileChooser: () => Effect.succeed(false),
@@ -234,6 +236,7 @@ it.effect.each([
     let attachments = 0;
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: () => Effect.succeedNone,
       answerFileChooser: () => Effect.succeed(false),
@@ -275,6 +278,7 @@ it.effect("serves a tab's download only to an authorized session", () =>
     const requests: Array<unknown> = [];
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: (input) =>
         Effect.sync(() => {
@@ -323,6 +327,7 @@ it.effect("passes uploaded files to the page's open picker and needs operate sco
     const answers: Array<{ chooserId: string; files: Array<{ name: string; text: string }> }> = [];
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: () => Effect.succeedNone,
       answerFileChooser: (input) =>
@@ -392,6 +397,7 @@ it.effect.each([
   Effect.gen(function* () {
     const browser = ServerBrowser.ServerBrowser.of({
       clearProfile: () => Effect.void,
+      open: () => Effect.die("unused"),
       profileReporter: Effect.succeed(() => Effect.void),
       openDownload: () => Effect.succeedNone,
       answerFileChooser: () => Effect.succeed(false),

apps/server/src/ws.ts

@@ -3202,7 +3202,7 @@ export const layerWsRpc = (
               (unsubscribe) => Effect.sync(unsubscribe),
             ),
           ),
-        [WS_METHODS.previewOpen]: (input) => previewManager.open(input),
+        [WS_METHODS.previewOpen]: (input) => serverBrowser.open(input),
         [WS_METHODS.previewResize]: (input) => previewManager.resize(input),
         [WS_METHODS.previewAdjust]: (input) => previewManager.adjust(input),
         [WS_METHODS.previewClose]: (input) => previewManager.close(input),

apps/web/src/browser/ElectronBrowserHost.tsx

@@ -105,6 +105,7 @@ function openLinkInPreview({ tabId, url, background }: DesktopPreviewOpenLinkEve
     url,
     openPreview: (input) => runAtomCommand(appAtomRegistry, previewEnvironment.open, input),
     profileId: source.snapshot.profileId,
+    openerTabId: source.snapshot.tabId,
     background,
   });
 }

apps/web/src/browser/openFileInPreview.ts

@@ -61,6 +61,7 @@ export async function openUrlInPreview<E>(input: {
   readonly url: string;
   readonly openPreview: OpenPreviewMutation<E>;
   readonly profileId?: PreviewOpenInput["profileId"];
+  readonly openerTabId?: PreviewOpenInput["openerTabId"];
   readonly background?: boolean;
 }): Promise<AtomCommandResult<void, E | BrowserSettingsReadError>> {
   // Read before any await: a side chat pane that unmounts meanwhile drops its host mapping.
@@ -86,6 +87,7 @@ export async function openUrlInPreview<E>(input: {
       viewport: defaults.viewport,
       profileId: input.profileId ?? defaults.profileId,
       ...(runtime === undefined ? {} : { runtime }),
+      ...(input.openerTabId === undefined ? {} : { openerTabId: input.openerTabId }),
     },
   });
   return mapAtomCommandResult(result, (snapshot) => {

packages/contracts/src/preview.ts

@@ -176,6 +176,7 @@ export const PreviewOpenInput = Schema.Struct({
   profileId: Schema.optional(BrowserProfileId),
   runtime: Schema.optional(PreviewRuntime),
   reveal: Schema.optional(Schema.Boolean),
+  openerTabId: Schema.optional(PreviewTabId),
 });
 export type PreviewOpenInput = typeof PreviewOpenInput.Type;