hermes-agent/hermes_cli/bang_shell.py

"""``!<command>`` shell mode for the interactive CLI.

``!git status`` at the composer runs directly in the session's working directory. The model is
never invoked — no user/assistant message or tool result enters history — so a bang command costs
zero tokens and cannot perturb role alternation or the prompt cache. CLI-only by design:
gateway/API/cron sessions have their own shells and no composer (:func:`bang_shell_enabled`).
"""

from __future__ import annotations

import os
import subprocess
from contextlib import suppress
from typing import Optional

USAGE_HINT = "Usage: !<command> — run a shell command without spending a model turn (e.g. !git status)"

# Interactive convenience, not agent work: keep the ceiling well under the terminal tool's foreground
# cap so an accidental `!sleep 999` cannot wedge the composer (the user can Ctrl+C anyway).
DEFAULT_TIMEOUT = 120


def is_bang_command(text: Optional[str]) -> bool:
    """True when *text* is a ``!`` shell-mode submission.

    Only a leading ``!`` (after surrounding whitespace) counts; ``fix the bug!`` is an ordinary
    prompt and must reach the agent untouched.
    """
    return isinstance(text, str) and text.strip().startswith("!")


def parse_bang_command(text: str) -> str:
    """The shell command inside a bang submission (``""`` when bare).

    ``!  ls -la`` -> ``ls -la``; ``!!`` -> ``!`` — a literal second bang belongs to the user's shell
    (history expansion), not to Hermes.
    """
    return text.strip()[1:].strip() if is_bang_command(text) else ""


def bang_shell_enabled() -> bool:
    """True only for interactive local CLI sessions.

    Gateway, API, and cron sessions never reach the composer and their users already have a shell;
    running arbitrary commands for them would be a remote-execution surface with no approving human
    at the keyboard.
    """
    try:
        from utils import env_var_enabled
    except Exception:  # pragma: no cover - utils is always importable in-tree
        def env_var_enabled(name, default=""):  # type: ignore[misc]
            return str(os.getenv(name, default)).strip().lower() in {"1", "true", "yes", "on"}

    return not (env_var_enabled("HERMES_GATEWAY_SESSION") or env_var_enabled("HERMES_CRON_SESSION")
                or (os.getenv("HERMES_SESSION_PLATFORM") or "").strip())


def resolve_bang_cwd(session_key: Optional[str] = None) -> Optional[str]:
    """The directory a bang command should run in.

    Mirrors the terminal tool's order so ``!pwd`` matches the agent's own commands: the session's
    recorded ``cd`` state first, then the configured ``TERMINAL_CWD``/backend default.
    """
    try:
        from tools.terminal_tool import _get_env_config, get_session_cwd
        return get_session_cwd(session_key) or (_get_env_config() or {}).get("cwd") or None
    except Exception:
        return None


def check_bang_approval(command: str) -> dict:
    """Run *command* through the terminal tool's approval gate.

    Reuses ``tools.terminal_tool._check_all_guards`` — exactly what ``terminal_tool()`` calls — so the
    hardline blocklist, user deny rules and the dangerous-command prompt all apply
    to user-typed bang commands too. Returns the gate's ``{"approved": bool, "message": ...}``;
    falls back to *approved* only when the gate itself cannot be imported (a broken install, not a
    policy decision).
    """
    try:
        from tools.terminal_tool import _check_all_guards
    except Exception:
        return {"approved": True, "message": None}

    # Bang commands always run locally in the CLI process, never inside a remote/sandbox backend.
    return _check_all_guards(command, "local", has_host_access=False)


def _bang_env() -> dict:
    """Environment for a bang command with Hermes-managed secrets filtered.

    The CLI process holds every provider API key; a user-typed command may still run a third-party
    script, so reuse the sanitizer ``quick_commands`` and the local terminal backend use. If that
    boundary is unavailable, let the launch fail rather than passing the CLI's full environment.
    """
    from tools.environments.local import build_subprocess_env
    return build_subprocess_env()


def run_bang_command(command: str, *, cwd: Optional[str] = None, timeout: int = DEFAULT_TIMEOUT, writer=None) -> int:
    """Execute *command*, streaming merged stdout/stderr through *writer* (default ``print``); return the exit code.

    Output exists only on the user's terminal — nothing is returned for insertion into history.
    """
    emit = writer or (lambda line: print(line, end="" if line.endswith("\n") else "\n"))
    run_cwd = os.path.expanduser(cwd) if cwd else None
    if run_cwd and not os.path.isdir(run_cwd):
        run_cwd = None
    try:
        from hermes_cli._subprocess_compat import windows_hide_flags
        creationflags = windows_hide_flags()
    except Exception:
        creationflags = 0
    try:
        # shell=True is intentional (matches quick_commands): the human typed this, not the model.
        proc = subprocess.Popen(
            command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True,
            encoding="utf-8", errors="replace", cwd=run_cwd, env=_bang_env(),
            creationflags=creationflags)
    except Exception as exc:
        emit(f"!: failed to run command: {exc}")
        return 127
    try:
        if proc.stdout is not None:
            for line in proc.stdout:
                emit(line.rstrip("\n"))
        proc.wait(timeout=timeout)
    except subprocess.TimeoutExpired:
        proc.kill()
        emit(f"!: command timed out after {timeout}s")
        return 124
    except KeyboardInterrupt:
        # Ctrl+C interrupts the command, not the Hermes session.
        proc.kill()
        emit("!: interrupted")
        return 130
    finally:
        if proc.stdout is not None:
            with suppress(Exception):
                proc.stdout.close()
    return int(proc.returncode or 0)