fix: handle empty sudo password and false prompts

cli-config.yaml.example

@@ -117,7 +117,8 @@ terminal:
   timeout: 180
   docker_mount_cwd_to_workspace: false  # SECURITY: off by default. Opt in to mount the launch cwd into Docker /workspace.
   lifetime_seconds: 300
-  # sudo_password: ""  # Enable sudo commands (pipes via sudo -S) - SECURITY WARNING: plaintext!
+  # sudo_password: "hunter2"  # Optional: pipe a sudo password via sudo -S. SECURITY WARNING: plaintext.
+  # sudo_password: ""         # Explicit empty password: try empty and never open the interactive sudo prompt.
 
 # -----------------------------------------------------------------------------
 # OPTION 2: SSH remote execution
@@ -208,13 +209,18 @@ terminal:
 #
 # SECURITY WARNING: Password stored in plaintext!
 #
-# INTERACTIVE PROMPT: If no sudo_password is set and the CLI is running,
+# INTERACTIVE PROMPT: If sudo_password is unset and the CLI is running,
 # you'll be prompted to enter your password when sudo is needed:
 # - 45-second timeout (auto-skips if no input)
 # - Press Enter to skip (command fails gracefully)
 # - Password is hidden while typing
 # - Password is cached for the session
 #
+# EMPTY PASSWORDS: Setting sudo_password to an explicit empty string is different
+# from leaving it unset. Hermes will try an empty password via `sudo -S` and
+# will not open the interactive prompt. This is useful for passwordless sudo,
+# Touch ID sudo setups, and environments where prompting is just noise.
+#
 # ALTERNATIVES:
 # - SSH backend: Configure passwordless sudo on the remote server
 # - Containers: Run as root inside the container (no sudo needed)

cli.py

@@ -1546,6 +1546,7 @@ class HermesCLI:
         self._clarify_deadline = 0
         self._sudo_state = None
         self._sudo_deadline = 0
+        self._modal_input_snapshot = None
         self._approval_state = None
         self._approval_deadline = 0
         self._approval_lock = threading.Lock()
@@ -6205,6 +6206,7 @@ class HermesCLI:
         timeout = 45
         response_queue = queue.Queue()
 
+        self._capture_modal_input_snapshot()
         self._sudo_state = {
             "response_queue": response_queue,
         }
@@ -6217,6 +6219,7 @@ class HermesCLI:
                 result = response_queue.get(timeout=1)
                 self._sudo_state = None
                 self._sudo_deadline = 0
+                self._restore_modal_input_snapshot()
                 self._invalidate()
                 if result:
                     _cprint(f"\n{_DIM}  ✓ Password received (cached for session){_RST}")
@@ -6231,6 +6234,7 @@ class HermesCLI:
 
         self._sudo_state = None
         self._sudo_deadline = 0
+        self._restore_modal_input_snapshot()
         self._invalidate()
         _cprint(f"\n{_DIM}  ⏱ Timeout — continuing without sudo{_RST}")
         return ""
@@ -6403,6 +6407,33 @@ class HermesCLI:
     def _secret_capture_callback(self, var_name: str, prompt: str, metadata=None) -> dict:
         return prompt_for_secret(self, var_name, prompt, metadata)
 
+    def _capture_modal_input_snapshot(self) -> None:
+        """Temporarily clear the input buffer and save the user's in-progress draft."""
+        if self._modal_input_snapshot is not None or not getattr(self, "_app", None):
+            return
+        try:
+            buf = self._app.current_buffer
+            self._modal_input_snapshot = {
+                "text": buf.text,
+                "cursor_position": buf.cursor_position,
+            }
+            buf.reset()
+        except Exception:
+            self._modal_input_snapshot = None
+
+    def _restore_modal_input_snapshot(self) -> None:
+        """Restore any draft text that was present before a modal prompt opened."""
+        snapshot = self._modal_input_snapshot
+        self._modal_input_snapshot = None
+        if not snapshot or not getattr(self, "_app", None):
+            return
+        try:
+            buf = self._app.current_buffer
+            buf.text = snapshot.get("text", "")
+            buf.cursor_position = min(snapshot.get("cursor_position", 0), len(buf.text))
+        except Exception:
+            pass
+
     def _submit_secret_response(self, value: str) -> None:
         if not self._secret_state:
             return
@@ -7130,6 +7161,7 @@ class HermesCLI:
         # Sudo password prompt state (similar mechanism to clarify)
         self._sudo_state = None         # dict with response_queue when active
         self._sudo_deadline = 0
+        self._modal_input_snapshot = None
 
         # Dangerous command approval state (similar mechanism to clarify)
         self._approval_state = None     # dict with command, description, choices, selected, response_queue
@@ -7201,7 +7233,6 @@ class HermesCLI:
                 text = event.app.current_buffer.text
                 self._sudo_state["response_queue"].put(text)
                 self._sudo_state = None
-                event.app.current_buffer.reset()
                 event.app.invalidate()
                 return
 
@@ -7406,7 +7437,6 @@ class HermesCLI:
             if self._sudo_state:
                 self._sudo_state["response_queue"].put("")
                 self._sudo_state = None
-                event.app.current_buffer.reset()
                 event.app.invalidate()
                 return
 

hermes_cli/config.py

@@ -1217,7 +1217,7 @@ OPTIONAL_ENV_VARS = {
         "category": "setting",
     },
     "SUDO_PASSWORD": {
-        "description": "Sudo password for terminal commands requiring root access",
+        "description": "Sudo password for terminal commands requiring root access; set to an explicit empty string to try empty without prompting",
         "prompt": "Sudo password",
         "url": None,
         "password": True,

tests/cli/test_cli_approval_ui.py

@@ -2,22 +2,65 @@ import queue
 import threading
 import time
 from types import SimpleNamespace
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
+import cli as cli_module
 from cli import HermesCLI
 
 
+class _FakeBuffer:
+    def __init__(self, text="", cursor_position=None):
+        self.text = text
+        self.cursor_position = len(text) if cursor_position is None else cursor_position
+
+    def reset(self, append_to_history=False):
+        self.text = ""
+        self.cursor_position = 0
+
+
 def _make_cli_stub():
     cli = HermesCLI.__new__(HermesCLI)
     cli._approval_state = None
     cli._approval_deadline = 0
     cli._approval_lock = threading.Lock()
+    cli._sudo_state = None
+    cli._sudo_deadline = 0
+    cli._modal_input_snapshot = None
     cli._invalidate = MagicMock()
-    cli._app = SimpleNamespace(invalidate=MagicMock())
+    cli._app = SimpleNamespace(invalidate=MagicMock(), current_buffer=_FakeBuffer())
     return cli
 
 
 class TestCliApprovalUi:
+    def test_sudo_prompt_restores_existing_draft_after_response(self):
+        cli = _make_cli_stub()
+        cli._app.current_buffer = _FakeBuffer("draft command", cursor_position=5)
+        result = {}
+
+        def _run_callback():
+            result["value"] = cli._sudo_password_callback()
+
+        with patch.object(cli_module, "_cprint"):
+            thread = threading.Thread(target=_run_callback, daemon=True)
+            thread.start()
+
+            deadline = time.time() + 2
+            while cli._sudo_state is None and time.time() < deadline:
+                time.sleep(0.01)
+
+            assert cli._sudo_state is not None
+            assert cli._app.current_buffer.text == ""
+
+            cli._app.current_buffer.text = "secret"
+            cli._app.current_buffer.cursor_position = len("secret")
+            cli._sudo_state["response_queue"].put("secret")
+
+            thread.join(timeout=2)
+
+        assert result["value"] == "secret"
+        assert cli._app.current_buffer.text == "draft command"
+        assert cli._app.current_buffer.cursor_position == 5
+
     def test_approval_callback_includes_view_for_long_commands(self):
         cli = _make_cli_stub()
         command = "sudo dd if=/tmp/githubcli-keyring.gpg of=/usr/share/keyrings/githubcli-archive-keyring.gpg bs=4M status=progress"

tests/tools/test_terminal_tool.py

@@ -0,0 +1,90 @@
+"""Regression tests for sudo detection and sudo password handling."""
+
+import tools.terminal_tool as terminal_tool
+
+
+def setup_function():
+    terminal_tool._cached_sudo_password = ""
+
+
+def teardown_function():
+    terminal_tool._cached_sudo_password = ""
+
+
+def test_searching_for_sudo_does_not_trigger_rewrite(monkeypatch):
+    monkeypatch.delenv("SUDO_PASSWORD", raising=False)
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+
+    command = "rg --line-number --no-heading --with-filename 'sudo' . | head -n 20"
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command(command)
+
+    assert transformed == command
+    assert sudo_stdin is None
+
+
+def test_printf_literal_sudo_does_not_trigger_rewrite(monkeypatch):
+    monkeypatch.delenv("SUDO_PASSWORD", raising=False)
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+
+    command = "printf '%s\\n' sudo"
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command(command)
+
+    assert transformed == command
+    assert sudo_stdin is None
+
+
+def test_non_command_argument_named_sudo_does_not_trigger_rewrite(monkeypatch):
+    monkeypatch.delenv("SUDO_PASSWORD", raising=False)
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+
+    command = "grep -n sudo README.md"
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command(command)
+
+    assert transformed == command
+    assert sudo_stdin is None
+
+
+def test_actual_sudo_command_uses_configured_password(monkeypatch):
+    monkeypatch.setenv("SUDO_PASSWORD", "testpass")
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command("sudo apt install -y ripgrep")
+
+    assert transformed == "sudo -S -p '' apt install -y ripgrep"
+    assert sudo_stdin == "testpass\n"
+
+
+def test_actual_sudo_after_leading_env_assignment_is_rewritten(monkeypatch):
+    monkeypatch.setenv("SUDO_PASSWORD", "testpass")
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command("DEBUG=1 sudo whoami")
+
+    assert transformed == "DEBUG=1 sudo -S -p '' whoami"
+    assert sudo_stdin == "testpass\n"
+
+
+def test_explicit_empty_sudo_password_tries_empty_without_prompt(monkeypatch):
+    monkeypatch.setenv("SUDO_PASSWORD", "")
+    monkeypatch.setenv("HERMES_INTERACTIVE", "1")
+
+    def _fail_prompt(*_args, **_kwargs):
+        raise AssertionError("interactive sudo prompt should not run for explicit empty password")
+
+    monkeypatch.setattr(terminal_tool, "_prompt_for_sudo_password", _fail_prompt)
+
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command("sudo true")
+
+    assert transformed == "sudo -S -p '' true"
+    assert sudo_stdin == "\n"
+
+
+def test_cached_sudo_password_is_used_when_env_is_unset(monkeypatch):
+    monkeypatch.delenv("SUDO_PASSWORD", raising=False)
+    monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)
+    terminal_tool._cached_sudo_password = "cached-pass"
+
+    transformed, sudo_stdin = terminal_tool._transform_sudo_command("echo ok && sudo whoami")
+
+    assert transformed == "echo ok && sudo -S -p '' whoami"
+    assert sudo_stdin == "cached-pass\n"

tools/terminal_tool.py

@@ -326,7 +326,6 @@ def _prompt_for_sudo_password(timeout_seconds: int = 45) -> str:
         if "HERMES_SPINNER_PAUSE" in os.environ:
             del os.environ["HERMES_SPINNER_PAUSE"]
 
-
 def _safe_command_preview(command: Any, limit: int = 200) -> str:
     """Return a log-safe preview for possibly-invalid command values."""
     if command is None:
@@ -338,6 +337,110 @@ def _safe_command_preview(command: Any, limit: int = 200) -> str:
     except Exception:
         return f"<{type(command).__name__}>"
 
+def _looks_like_env_assignment(token: str) -> bool:
+    """Return True when *token* is a leading shell environment assignment."""
+    if "=" not in token or token.startswith("="):
+        return False
+    name, _value = token.split("=", 1)
+    return bool(re.match(r"^[A-Za-z_][A-Za-z0-9_]*$", name))
+
+
+def _read_shell_token(command: str, start: int) -> tuple[str, int]:
+    """Read one shell token, preserving quotes/escapes, starting at *start*."""
+    i = start
+    n = len(command)
+
+    while i < n:
+        ch = command[i]
+        if ch.isspace() or ch in ";|&()":
+            break
+        if ch == "'":
+            i += 1
+            while i < n and command[i] != "'":
+                i += 1
+            if i < n:
+                i += 1
+            continue
+        if ch == '"':
+            i += 1
+            while i < n:
+                inner = command[i]
+                if inner == "\\" and i + 1 < n:
+                    i += 2
+                    continue
+                if inner == '"':
+                    i += 1
+                    break
+                i += 1
+            continue
+        if ch == "\\" and i + 1 < n:
+            i += 2
+            continue
+        i += 1
+
+    return command[start:i], i
+
+
+def _rewrite_real_sudo_invocations(command: str) -> tuple[str, bool]:
+    """Rewrite only real unquoted sudo command words, not plain text mentions."""
+    out: list[str] = []
+    i = 0
+    n = len(command)
+    command_start = True
+    found = False
+
+    while i < n:
+        ch = command[i]
+
+        if ch.isspace():
+            out.append(ch)
+            if ch == "\n":
+                command_start = True
+            i += 1
+            continue
+
+        if ch == "#" and command_start:
+            comment_end = command.find("\n", i)
+            if comment_end == -1:
+                out.append(command[i:])
+                break
+            out.append(command[i:comment_end])
+            i = comment_end
+            continue
+
+        if command.startswith("&&", i) or command.startswith("||", i) or command.startswith(";;", i):
+            out.append(command[i:i + 2])
+            i += 2
+            command_start = True
+            continue
+
+        if ch in ";|&(":
+            out.append(ch)
+            i += 1
+            command_start = True
+            continue
+
+        if ch == ")":
+            out.append(ch)
+            i += 1
+            command_start = False
+            continue
+
+        token, next_i = _read_shell_token(command, i)
+        if command_start and token == "sudo":
+            out.append("sudo -S -p ''")
+            found = True
+        else:
+            out.append(token)
+
+        if command_start and _looks_like_env_assignment(token):
+            command_start = True
+        else:
+            command_start = False
+        i = next_i
+
+    return "".join(out), found
+
 
 def _transform_sudo_command(command: str | None) -> tuple[str | None, str | None]:
     """
@@ -374,41 +477,27 @@ def _transform_sudo_command(command: str | None) -> tuple[str | None, str | None
       Command runs as-is (fails gracefully with "sudo: a password is required").
     """
     global _cached_sudo_password
-    import re
 
-    # Check if command even contains sudo
     if command is None:
         return None, None
+    transformed, has_real_sudo = _rewrite_real_sudo_invocations(command)
+    if not has_real_sudo:
+        return command, None
 
-    if not re.search(r'\bsudo\b', command):
+    has_configured_password = "SUDO_PASSWORD" in os.environ
-        return command, None  # No sudo in command, nothing to do
+    sudo_password = os.environ.get("SUDO_PASSWORD", "") if has_configured_password else _cached_sudo_password
 
-    # Try to get password from: env var -> session cache -> interactive prompt
+    if not has_configured_password and not sudo_password and os.getenv("HERMES_INTERACTIVE"):
-    sudo_password = os.getenv("SUDO_PASSWORD", "") or _cached_sudo_password
-
-    if not sudo_password:
-        # No password configured - check if we're in interactive mode
-        if os.getenv("HERMES_INTERACTIVE"):
-            # Prompt user for password
         sudo_password = _prompt_for_sudo_password(timeout_seconds=45)
         if sudo_password:
-                _cached_sudo_password = sudo_password  # Cache for session
+            _cached_sudo_password = sudo_password
 
-    if not sudo_password:
+    if has_configured_password or sudo_password:
-        return command, None  # No password, let it fail gracefully
-
-    def replace_sudo(match):
-        # Replace bare 'sudo' with 'sudo -S -p ""'.
-        # The password is returned as sudo_stdin and must be written to the
-        # process's stdin pipe by the caller — it never appears in any
-        # command-line argument or shell string.
-        return "sudo -S -p ''"
-
-    # Match 'sudo' at word boundaries (not 'visudo' or 'sudoers')
-    transformed = re.sub(r'\bsudo\b', replace_sudo, command)
         # Trailing newline is required: sudo -S reads one line for the password.
         return transformed, sudo_password + "\n"
 
+    return command, None
+
 
 # Environment classes now live in tools/environments/
 from tools.environments.local import LocalEnvironment as _LocalEnvironment