feat(browser): spin up browser cells from the command center

packages/core/src/command-center/cells.ts

@@ -1,9 +1,11 @@
 import type { AgentSession, WorkspaceMode } from "@posthog/shared";
 import type { Task } from "@posthog/shared/domain-types";
 import {
+  getBrowserCellUrl,
   getTerminalCellCwd,
   getTerminalCellId,
   isBrainrotCell,
+  isBrowserCell,
   isTerminalCell,
 } from "./grid";
 import { type CellStatus, deriveStatus, getRepoName } from "./status";
@@ -21,6 +23,7 @@ export interface CommandCenterCellData {
   // Standalone terminal slot, independent of any agent run.
   terminalId: string | null;
   terminalCwd: string | null;
+  browserUrl: string | null;
 }
 
 export interface BuildCellsInput {
@@ -39,6 +42,7 @@ const EMPTY_CELL_DATA = {
   isBrainrot: false,
   terminalId: null,
   terminalCwd: null,
+  browserUrl: null,
 };
 
 export function buildCommandCenterCells(
@@ -60,6 +64,14 @@ export function buildCommandCenterCells(
       };
     }
 
+    if (isBrowserCell(cellValue)) {
+      return {
+        ...EMPTY_CELL_DATA,
+        cellIndex,
+        browserUrl: getBrowserCellUrl(cellValue),
+      };
+    }
+
     const taskId = cellValue;
     const task = taskId ? taskById.get(taskId) : undefined;
     const session = taskId ? sessionByTaskId.get(taskId) : undefined;

packages/core/src/command-center/grid.test.ts

@@ -2,13 +2,16 @@ import { describe, expect, it } from "vitest";
 import {
   BRAINROT_CELL,
   clampZoom,
+  getBrowserCellUrl,
   getCellCount,
   getCellSessionId,
   getGridDimensions,
   getTerminalCellCwd,
   getTerminalCellId,
   isBrainrotCell,
+  isBrowserCell,
   isTerminalCell,
+  makeBrowserCellValue,
   makeTerminalCellValue,
   resizeCells,
 } from "./grid";
@@ -92,6 +95,35 @@ describe("terminal cells", () => {
   });
 });
 
+describe("browser cells", () => {
+  it.each([
+    "about:blank",
+    "https://posthog.com",
+    // A url containing the delimiter and prefix-like text must survive intact.
+    "https://example.com/x?to=__browser__:https://evil.com",
+  ])("round-trips %j through the cell value", (url) => {
+    const value = makeBrowserCellValue(url);
+    expect(isBrowserCell(value)).toBe(true);
+    expect(getBrowserCellUrl(value)).toBe(url);
+  });
+
+  it("round-trips an empty url (blank browser cell)", () => {
+    const value = makeBrowserCellValue("");
+    expect(isBrowserCell(value)).toBe(true);
+    expect(getBrowserCellUrl(value)).toBe("");
+  });
+
+  it.each([
+    { value: "some-task-uuid", expected: false },
+    { value: BRAINROT_CELL, expected: false },
+    { value: makeTerminalCellValue("t1"), expected: false },
+    { value: null, expected: false },
+  ])("isBrowserCell($value) -> $expected", ({ value, expected }) => {
+    expect(isBrowserCell(value)).toBe(expected);
+    expect(getBrowserCellUrl(value)).toBeNull();
+  });
+});
+
 describe("getCellSessionId", () => {
   it("formats the cell session id", () => {
     expect(getCellSessionId(2)).toBe("cc-cell-2");

packages/core/src/command-center/grid.ts

@@ -49,6 +49,23 @@ export function getTerminalCellCwd(value: string | null): string | null {
   return colon === -1 ? null : decodeURIComponent(rest.slice(colon + 1));
 }
 
+// Reserved prefix for standalone browser cells; the whole remainder is the
+// url, so urls containing ":" or the prefix text are safe. Never collides with
+// task ids (uuids), BRAINROT_CELL, or terminal cells.
+export const BROWSER_CELL_PREFIX = "__browser__:";
+
+export function isBrowserCell(value: string | null): value is string {
+  return value?.startsWith(BROWSER_CELL_PREFIX) ?? false;
+}
+
+export function makeBrowserCellValue(url: string): string {
+  return `${BROWSER_CELL_PREFIX}${url}`;
+}
+
+export function getBrowserCellUrl(value: string | null): string | null {
+  return isBrowserCell(value) ? value.slice(BROWSER_CELL_PREFIX.length) : null;
+}
+
 export function getGridDimensions(preset: LayoutPreset): GridDimensions {
   const [cols, rows] = preset.split("x").map(Number);
   return { cols, rows };

packages/ui/src/features/command-center/commandCenterStore.ts

@@ -2,7 +2,9 @@ import {
   BRAINROT_CELL,
   clampZoom,
   getCellCount,
+  isBrowserCell,
   type LayoutPreset,
+  makeBrowserCellValue,
   makeTerminalCellValue,
   resizeCells,
   ZOOM_STEP,
@@ -39,6 +41,8 @@ interface CommandCenterStoreActions {
     terminalId: string,
     cwd?: string,
   ) => void;
+  setBrowserCell: (cellIndex: number, url: string) => void;
+  updateBrowserCellUrl: (cellIndex: number, url: string) => void;
   autofillCells: (taskIds: string[]) => void;
   clearCell: (cellIndex: number) => void;
   removeTaskById: (taskId: string) => void;
@@ -136,6 +140,28 @@ export const useCommandCenterStore = create<CommandCenterStore>()(
           };
         }),
 
+      setBrowserCell: (cellIndex, url) =>
+        set((state) => {
+          if (cellIndex < 0 || cellIndex >= state.cells.length) return state;
+          const cells = [...state.cells];
+          cells[cellIndex] = makeBrowserCellValue(url);
+          return {
+            cells,
+            activeTaskId: null,
+            activeCellIndex: cellIndex,
+            creatingCells: state.creatingCells.filter((i) => i !== cellIndex),
+            hasAutofilled: true,
+          };
+        }),
+
+      updateBrowserCellUrl: (cellIndex, url) =>
+        set((state) => {
+          if (!isBrowserCell(state.cells[cellIndex] ?? null)) return state;
+          const cells = [...state.cells];
+          cells[cellIndex] = makeBrowserCellValue(url);
+          return { cells };
+        }),
+
       autofillCells: (taskIds) =>
         set((state) => {
           // Grid already full: nothing to place, but the bootstrap is done.

packages/ui/src/features/command-center/components/CommandCenterPanel.tsx

@@ -4,6 +4,7 @@ import {
   Desktop,
   Folder,
   GitFork,
+  Globe,
   Lightning,
   Plus,
   Terminal,
@@ -12,14 +13,24 @@ import {
 import { isBrainrotCell } from "@posthog/core/command-center/grid";
 import { ANALYTICS_EVENTS, type WorkspaceMode } from "@posthog/shared";
 import type { Task } from "@posthog/shared/domain-types";
+import {
+  BrowserPanel,
+  useBrowserEnabled,
+} from "@posthog/ui/features/browser/BrowserPanel";
 import { useSettingsStore } from "@posthog/ui/features/settings/settingsStore";
 import { destroyShellTerminal } from "@posthog/ui/features/terminal/destroyShellTerminal";
 import { ShellTerminal } from "@posthog/ui/features/terminal/ShellTerminal";
 import { openTask } from "@posthog/ui/router/useOpenTask";
 import { track } from "@posthog/ui/shell/analytics";
 import { secureRandomString } from "@posthog/ui/utils/random";
 import { Flex, Spinner, Text } from "@radix-ui/themes";
-import { useCallback, useEffect, useRef, useState } from "react";
+import {
+  type ReactNode,
+  useCallback,
+  useEffect,
+  useRef,
+  useState,
+} from "react";
 import { useFolders } from "../../folders/useFolders";
 import { useCloudPrUrl } from "../../git-interaction/useCloudPrUrl";
 import { useDraftStore } from "../../message-editor/draftStore";
@@ -116,11 +127,13 @@ function EmptyCell({ cellIndex }: { cellIndex: number }) {
   const assignTask = useCommandCenterStore((s) => s.assignTask);
   const setBrainrotCell = useCommandCenterStore((s) => s.setBrainrotCell);
   const setTerminalCell = useCommandCenterStore((s) => s.setTerminalCell);
+  const setBrowserCell = useCommandCenterStore((s) => s.setBrowserCell);
   const startCreating = useCommandCenterStore((s) => s.startCreating);
   const stopCreating = useCommandCenterStore((s) => s.stopCreating);
   const layout = useCommandCenterStore((s) => s.layout);
   const cells = useCommandCenterStore((s) => s.cells);
   const brainrotMode = useSettingsStore((s) => s.brainrotMode);
+  const browserEnabled = useBrowserEnabled();
   const clearDraft = useDraftStore((s) => s.actions.setDraft);
 
   const sessionId = getCellSessionId(cellIndex);
@@ -140,6 +153,10 @@ function EmptyCell({ cellIndex }: { cellIndex: number }) {
     [setTerminalCell, cellIndex],
   );
 
+  const handleNewBrowser = useCallback(() => {
+    setBrowserCell(cellIndex, "about:blank");
+  }, [setBrowserCell, cellIndex]);
+
   const handleTaskCreated = useCallback(
     (task: Task) => {
       assignTask(cellIndex, task.id);
@@ -199,6 +216,7 @@ function EmptyCell({ cellIndex }: { cellIndex: number }) {
           onOpenChange={setSelectorOpen}
           onNewTask={() => startCreating(cellIndex)}
           onNewTerminal={handleNewTerminal}
+          onNewBrowser={browserEnabled ? handleNewBrowser : undefined}
           onBrainrot={brainrotMode ? handleBrainrot : undefined}
         >
           <button
@@ -279,6 +297,54 @@ function BrainrotCell({ cellIndex }: { cellIndex: number }) {
   );
 }
 
+// Shared chrome for every occupied command-center cell: a titled header with a
+// type icon, an optional badge slot, a remove button, and the cell body below.
+function CellFrame({
+  icon,
+  title,
+  headerExtra,
+  onRemove,
+  children,
+}: {
+  icon: ReactNode;
+  title: string;
+  headerExtra?: ReactNode;
+  onRemove: () => void;
+  children: ReactNode;
+}) {
+  return (
+    <Flex direction="column" height="100%">
+      <Flex
+        align="center"
+        gap="2"
+        px="2"
+        py="1"
+        className="shrink-0 border-gray-6 border-b"
+      >
+        {icon}
+        <Text
+          className="min-w-0 flex-1 truncate font-medium text-[12px]"
+          title={title}
+        >
+          {title}
+        </Text>
+        {headerExtra}
+        <button
+          type="button"
+          onClick={onRemove}
+          className="flex h-5 w-5 shrink-0 items-center justify-center rounded text-gray-10 transition-colors hover:bg-gray-4 hover:text-gray-12"
+          title="Remove from grid"
+        >
+          <X size={12} />
+        </button>
+      </Flex>
+      <Flex direction="column" className="min-h-0 flex-1">
+        {children}
+      </Flex>
+    </Flex>
+  );
+}
+
 function TerminalCell({
   cellIndex,
   terminalId,
@@ -300,37 +366,59 @@ function TerminalCell({
   }, [stateKey, clearCell, cellIndex]);
 
   return (
-    <Flex direction="column" height="100%">
-      <Flex
-        align="center"
-        gap="2"
-        px="2"
-        py="1"
-        className="shrink-0 border-gray-6 border-b"
-      >
-        <Terminal size={12} className="shrink-0 text-gray-10" />
-        <Text className="min-w-0 flex-1 truncate font-medium text-[12px]">
-          Terminal
-        </Text>
-        {folderName && (
+    <CellFrame
+      icon={<Terminal size={12} className="shrink-0 text-gray-10" />}
+      title="Terminal"
+      headerExtra={
+        folderName ? (
           <span className="inline-flex items-center gap-0.5 rounded bg-gray-3 px-1 py-0.5 text-[10px] text-gray-10">
             <Folder size={10} />
             {folderName}
           </span>
-        )}
-        <button
-          type="button"
-          onClick={handleRemove}
-          className="flex h-5 w-5 shrink-0 items-center justify-center rounded text-gray-10 transition-colors hover:bg-gray-4 hover:text-gray-12"
-          title="Remove from grid"
-        >
-          <X size={12} />
-        </button>
-      </Flex>
-      <Flex direction="column" className="min-h-0 flex-1">
-        <ShellTerminal cwd={cwd} stateKey={stateKey} />
-      </Flex>
-    </Flex>
+        ) : undefined
+      }
+      onRemove={handleRemove}
+    >
+      <ShellTerminal cwd={cwd} stateKey={stateKey} />
+    </CellFrame>
+  );
+}
+
+function hostnameOf(url: string): string | null {
+  try {
+    return new URL(url).hostname || null;
+  } catch {
+    return null;
+  }
+}
+
+function BrowserCell({ cellIndex, url }: { cellIndex: number; url: string }) {
+  const clearCell = useCommandCenterStore((s) => s.clearCell);
+  const updateBrowserCellUrl = useCommandCenterStore(
+    (s) => s.updateBrowserCellUrl,
+  );
+  // Page title once loaded; before that (e.g. a just-restored cell) the
+  // persisted url's hostname beats a bare "Browser".
+  const [title, setTitle] = useState<string | null>(null);
+  const label = title ?? hostnameOf(url) ?? "Browser";
+
+  const onUrlChange = useCallback(
+    (next: string) => updateBrowserCellUrl(cellIndex, next),
+    [updateBrowserCellUrl, cellIndex],
+  );
+
+  return (
+    <CellFrame
+      icon={<Globe size={12} className="shrink-0 text-gray-10" />}
+      title={label}
+      onRemove={() => clearCell(cellIndex)}
+    >
+      <BrowserPanel
+        url={url}
+        onUrlChange={onUrlChange}
+        onTitleChange={setTitle}
+      />
+    </CellFrame>
   );
 }
 
@@ -426,6 +514,11 @@ export function CommandCenterPanel({
     );
   }
 
+  // Empty-string url is a valid (blank) browser cell, so check against null.
+  if (cell.browserUrl !== null) {
+    return <BrowserCell cellIndex={cell.cellIndex} url={cell.browserUrl} />;
+  }
+
   if (!cell.taskId || !cell.task) {
     return <EmptyCell cellIndex={cell.cellIndex} />;
   }