Stop computer bash commands on the computer itself

The sandbox ignores sandbox_execute_bash's timeout and runs every call in
one shared shell session, so a command that never ended (a network read
without a timeout, a prompt) kept running after the call gave up, and
every later command on that computer, from any run, timed out behind it.
Each command now runs in its own bash under coreutils timeout (at most
ComputerCommandMaxSeconds, below McpToolTimeoutMs), reading no input, and
says when it was stopped.

Replies' env list says where each key comes from and that workspace,
computer and install-wide envs reach every bot there, so bots stop
telling users a workspace's keys must be set per bot. The computer
prompt says installed programs may be gone after a restart. An empty
open-only task list says closed tasks aren't shown, and update_task says
when a status was already set.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/data/app-data.ts

@@ -354,6 +354,13 @@ export const AppData = {
      * One MCP tool call gives up after this long without progress.
      */
     McpToolTimeoutMs: 5 * 60 * 1000,
+    /**
+     * A bash command on a computer is killed there after at most this long
+     * (`withCommandTimeout`), below `McpToolTimeoutMs`: the sandbox ignores
+     * its own `timeout` and runs every call in one shell session, so a
+     * command left running would hold up every later one on that computer.
+     */
+    ComputerCommandMaxSeconds: 270,
     /**
      * MCP servers set up in Settings, under MCPs: a stdio server runs in
      * `DATA_DIR/<McpDataDir>/<id>` (its setup installs there, so it

src/data/harness-prompts.ts

@@ -102,6 +102,7 @@ You work only in your own folders on the computer, never elsewhere in it: every
     dirs.shared_dir ? `\n- ${dirs.shared_dir}: shared with every bot in this workspace.` : ""
 }
 - The browser downloads to its own folder: move what you download into your folder straight away.
+- A computer can be restarted or rebuilt at any time, and only ${AppData.ComputerWorkspaceDir} and the browser's logins survive it. Programs you install (sudo apt-get install -y, pip, npm -g) may be gone afterwards: check for one first (command -v) and install it again when it's missing.
 
 What you make there (downloads, screenshots, a crawl, raw evidence, logs) is kept with the computer, not in your files, and it is not searchable.