feat(cli): add /update slash command to CLI and TUI (#23854)

* feat: add /update slash command to CLI and TUI

* test(cli): add Python tests for /update slash command

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(cli): address Copilot review for /update slash command

Route classic CLI /update through prompt_toolkit modal confirmation and
defer relaunch to the main-thread cleanup path after app.exit(). Tighten
Y/n semantics, add Python wrapper and catalog coverage tests, and assert
/update stays visible in the TUI command catalog.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(cli): address review feedback on /update command

- Replace raw input() with _prompt_text_input_modal in _handle_update_command
  to avoid EOF/hang/keystroke-leak races with prompt_toolkit's stdin ownership
- Fix confirmation logic: only proceed on recognized affirmative aliases
  (y/yes/1/ok); cancel on everything else including empty string, typos,
  and unrecognized input — matches all other [Y/n] prompts in the codebase
- Route relaunch through main-thread shutdown path: set _pending_relaunch
  and return False from process_command so process_loop triggers app.exit();
  run() then calls relaunch() after prompt_toolkit has restored terminal modes
  and after cleanup — safe on both POSIX (execvp) and Windows (subprocess+exit)
- Fix misleading docstring in test_update_command.py: the Vitest only covers
  the TypeScript slash handler that emits code 42, not the Python wrapper
  branch that acts on it
- Rewrite tests to use SimpleNamespace pattern (like test_destructive_slash_confirm)
  so _prompt_text_input_modal can be stubbed directly
- Add Python test for _launch_tui exit-code-42 → relaunch branch in main.py

Agent-Logs-Url: https://github.com/NousResearch/hermes-agent/sessions/f6da68cf-e7b1-4b7a-aed6-3d4b0f523bdb

Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

* fix(cli): polish test fixtures for /update command

- Remove unused _prompt_text_input from SimpleNamespace stub
- Use pytest.fail sentinel in managed-install guard test to catch unexpected modal invocations

Agent-Logs-Url: https://github.com/NousResearch/hermes-agent/sessions/f6da68cf-e7b1-4b7a-aed6-3d4b0f523bdb

Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

* chore: re-trigger CI after Copilot review fixes

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

cli.py

@@ -2830,6 +2830,11 @@ class HermesCLI:
         # process_command() when the user runs /exit --delete or /quit --delete.
         # Ported from google-gemini/gemini-cli#19332.
         self._delete_session_on_exit = False
+        # /update: when set, run() executes relaunch() after prompt_toolkit
+        # has fully exited and cleaned up terminal modes.  Set by
+        # _handle_update_command() so the relaunch happens on the main thread,
+        # not the background process_loop thread.
+        self._pending_relaunch: list[str] | None = None
         self._last_ctrl_c_time = 0
         self._clarify_state = None
         self._clarify_freetext = False
@@ -7948,6 +7953,9 @@ class HermesCLI:
             self._handle_copy_command(cmd_original)
         elif canonical == "debug":
             self._handle_debug_command()
+        elif canonical == "update":
+            if self._handle_update_command():
+                return False
         elif canonical == "paste":
             self._handle_paste_command()
         elif canonical == "image":
@@ -9230,6 +9238,58 @@ class HermesCLI:
         args = SimpleNamespace(lines=200, expire=7, local=False)
         run_debug_share(args)
 
+    def _handle_update_command(self) -> bool:
+        """Handle /update — update Hermes Agent to the latest version.
+
+        In the classic CLI this exits the session and relaunches as
+        ``hermes update`` so the user sees update output directly and gets
+        the new version on next launch.
+
+        Returns ``True`` when the update was confirmed (caller should trigger
+        app exit so the relaunch is deferred to the main thread after
+        prompt_toolkit cleans up terminal modes).  Returns ``False`` / falsy
+        when cancelled.
+        """
+        from hermes_cli.config import is_managed, format_managed_message
+
+        if is_managed():
+            print(f"  ✗ {format_managed_message('update Hermes Agent')}")
+            return False
+
+        # Use the prompt_toolkit-native modal so the confirmation panel
+        # renders properly above the composer and avoids raw input() races
+        # with the prompt_toolkit event loop (same pattern as
+        # _confirm_destructive_slash).
+        choices = [
+            ("once", "Update Now", "exit the current session and update Hermes Agent"),
+            ("cancel", "Cancel", "keep the current session"),
+        ]
+        raw = self._prompt_text_input_modal(
+            title="⚕  Update Hermes Agent",
+            detail="This will exit the current session and run `hermes update`.",
+            choices=choices,
+        )
+        if raw is None:
+            print("  🟡 /update cancelled.")
+            return False
+        choice = self._normalize_slash_confirm_choice(raw, choices)
+        if choice != "once":
+            print("  🟡 /update cancelled.")
+            return False
+
+        print()
+        print("  ⚕ Launching update...")
+        print()
+
+        # Store the relaunch args so run() can exec them from the main thread
+        # after prompt_toolkit exits and restores terminal modes.  Calling
+        # relaunch() directly here (from the process_loop daemon thread) would
+        # skip terminal cleanup on POSIX (execvp replaces the process mid-TUI)
+        # and only exit the worker thread on Windows (subprocess.run +
+        # sys.exit inside a non-main thread does not exit the process).
+        self._pending_relaunch = ["update"]
+        return True
+
     def _show_usage(self):
         """Show rate limits (if available) and session token usage."""
         if not self.agent:
@@ -13937,6 +13997,15 @@ class HermesCLI:
             _run_cleanup()
             self._print_exit_summary()
 
+        # Deferred relaunch: /update sets _pending_relaunch so the exec
+        # happens here — after prompt_toolkit has exited and fully restored
+        # terminal modes — rather than from the background process_loop
+        # thread (which would skip terminal cleanup on POSIX and only exit
+        # the worker thread on Windows).
+        if getattr(self, '_pending_relaunch', None):
+            from hermes_cli.relaunch import relaunch
+            relaunch(self._pending_relaunch, preserve_inherited=False)
+
 
 # ============================================================================
 # Main Entry Point