feat(cli): add hermes send to pipe script output to any messaging platform (#27188)

Introduces a thin CLI wrapper around the existing send_message_tool so
shell scripts, cron scripts, CI hooks, and monitoring daemons can reuse
the gateway's already-configured platform credentials without
reimplementing each platform's REST client.

  hermes send --to telegram "deploy finished"
  echo "RAM 92%" | hermes send --to telegram:-1001234567890
  hermes send --to discord:#ops --file report.md
  hermes send --to slack:#eng --subject "[CI]" --file build.log
  hermes send --list                  # all targets
  hermes send --list telegram         # filter by platform

Supports all platforms the send_message tool already does (Telegram,
Discord, Slack, Signal, SMS, WhatsApp, Matrix, Feishu, DingTalk, WeCom,
Weixin, Email, etc.), including threaded targets and #channel-name
resolution via the channel directory.

hermes_cli/send_cmd.py delegates to tools.send_message_tool.send_message_tool,
which means there is zero new platform-specific code. The subcommand just:

1. Bridges ~/.hermes/.env and top-level ~/.hermes/config.yaml scalars into
   os.environ (same bootstrap the gateway does at startup) — required so
   TELEGRAM_HOME_CHANNEL and friends are visible to load_gateway_config().
2. Resolves the message body from positional arg, --file, or piped stdin.
3. Calls the shared tool and translates its JSON result to exit codes:
   0 success, 1 delivery failure, 2 usage error.

No running gateway is required for bot-token platforms (Telegram, Discord,
Slack, Signal, SMS, WhatsApp) — the tool hits each platform's REST API
directly. Plugin platforms that rely on a live adapter connection still
need the gateway running; the error message is forwarded verbatim.

- New guide: website/docs/guides/pipe-script-output.md covering real-world
  patterns (memory watchdogs, CI hooks, cron pipes, long-running task
  completion pings) and the security/gateway notes.
- Cross-links added from automate-with-cron.md ("no LLM? use hermes send")
  and developer-guide/gateway-internals.md (delivery-path section).

tests/hermes_cli/test_send_cmd.py (20 tests, all green):

- Happy paths: positional message, stdin, --file, --file -, --subject,
  --json, --quiet.
- Error paths: missing --to, missing body, file not found, tool returns
  error payload (exit 1), tool skipped-send result (exit 0).
- --list: human output, --json output, platform filter, unknown platform.
- Env loader: bridges config.yaml scalars into env, does not override
  existing env vars, gracefully handles missing files.
- Registrar contract: register_send_subparser() returns a working parser.

Smoke-tested end-to-end against a live Telegram bot before commit.

hermes_cli/send_cmd.py

@@ -0,0 +1,445 @@
+"""CLI subcommand: ``hermes send`` — pipe text from shell scripts to any
+configured messaging platform (Telegram, Discord, Slack, Signal, SMS, etc.).
+
+This is a thin wrapper around ``tools.send_message_tool.send_message_tool``
+that exposes its functionality as a standalone CLI entry point so ops
+scripts, cron jobs, CI hooks, and monitoring daemons can reuse the gateway's
+already-configured credentials without having to reimplement each platform's
+REST API client.
+
+Design notes:
+
+* No LLM, no agent loop — the subcommand just resolves arguments, reads the
+  message body, calls the shared tool function, and prints/returns the
+  result. It is intentionally fast, cheap, and side-effect-only.
+* For platforms that send via bot token (Telegram, Discord, Slack, Signal,
+  SMS, WhatsApp-CloudAPI, …) no running gateway is required. The tool
+  talks directly to each platform's REST endpoint. For platforms that rely
+  on a persistent adapter connection (plugin platforms, Matrix in some
+  modes, …) a live gateway is needed; the underlying tool surfaces that
+  error to the caller.
+* Exit codes follow the classic Unix convention:
+    0 — delivery (or list) succeeded
+    1 — delivery failed at the platform level
+    2 — usage / argument / config error (argparse already uses 2)
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from pathlib import Path
+from typing import Optional
+
+
+_USAGE_EXIT = 2
+_FAILURE_EXIT = 1
+_SUCCESS_EXIT = 0
+
+
+def _read_message_body(
+    positional: Optional[str],
+    file_path: Optional[str],
+) -> Optional[str]:
+    """Resolve the message body from (in order):
+
+    1. An explicit positional message argument.
+    2. ``--file PATH`` or ``--file -`` (where ``-`` means stdin).
+    3. Piped stdin when it is not attached to a TTY.
+
+    Returns ``None`` when nothing is available — callers must treat that as
+    a usage error.
+    """
+    if positional:
+        return positional
+
+    if file_path:
+        if file_path == "-":
+            return sys.stdin.read()
+        try:
+            return Path(file_path).read_text()
+        except OSError as exc:
+            print(f"hermes send: cannot read {file_path}: {exc}", file=sys.stderr)
+            sys.exit(_USAGE_EXIT)
+
+    # Piped input: only consume stdin when it is not a TTY. Reading from a
+    # TTY would block the user in a half-broken "type your message" state,
+    # which is a poor default for an ops CLI.
+    if not sys.stdin.isatty():
+        data = sys.stdin.read()
+        if data:
+            return data
+
+    return None
+
+
+def _resolve_target(arg_to: Optional[str]) -> Optional[str]:
+    """Return a cleaned ``--to`` value, or ``None`` when nothing is set."""
+    if arg_to and arg_to.strip():
+        return arg_to.strip()
+    return None
+
+
+def _emit_result(
+    result_json: str,
+    *,
+    json_mode: bool,
+    quiet: bool,
+) -> int:
+    """Print the tool result in the requested format and return the exit code.
+
+    The underlying ``send_message_tool`` always returns a JSON string. We
+    parse it, decide success/failure, and format accordingly.
+    """
+    try:
+        payload = json.loads(result_json) if result_json else {}
+    except json.JSONDecodeError:
+        # Shouldn't happen with the shared tool, but be defensive — pass the
+        # raw string through so the user can still see what went wrong.
+        payload = {"error": "invalid JSON from send_message_tool", "raw": result_json}
+
+    if json_mode:
+        print(json.dumps(payload, indent=2))
+    elif quiet:
+        pass
+    else:
+        if payload.get("error"):
+            print(f"hermes send: {payload['error']}", file=sys.stderr)
+        elif payload.get("success"):
+            note = payload.get("note")
+            if note:
+                print(note)
+            else:
+                print("sent")
+        else:
+            # Unknown shape — dump it so nothing is silently dropped.
+            print(json.dumps(payload, indent=2))
+
+    if payload.get("error"):
+        return _FAILURE_EXIT
+    if payload.get("skipped"):
+        return _SUCCESS_EXIT
+    if payload.get("success"):
+        return _SUCCESS_EXIT
+    # Unknown / unexpected — treat as failure so scripts notice.
+    return _FAILURE_EXIT
+
+
+def _list_targets(platform_filter: Optional[str], *, json_mode: bool) -> int:
+    """Print the channel directory (all configured targets across platforms).
+
+    Uses ``load_directory()`` for structured JSON output and
+    ``format_directory_for_display()`` for the human-readable rendering that
+    the send_message tool itself shows to the model — keeps the two surfaces
+    identical.
+    """
+    try:
+        from gateway.channel_directory import (
+            format_directory_for_display,
+            load_directory,
+        )
+    except Exception as exc:
+        print(f"hermes send: failed to load channel directory: {exc}", file=sys.stderr)
+        return _FAILURE_EXIT
+
+    try:
+        raw = load_directory()
+    except Exception as exc:
+        print(f"hermes send: failed to read channel directory: {exc}", file=sys.stderr)
+        return _FAILURE_EXIT
+
+    platforms = dict(raw.get("platforms") or {})
+
+    if platform_filter:
+        key = platform_filter.strip().lower()
+        filtered = {k: v for k, v in platforms.items() if k.lower() == key}
+        if not filtered:
+            print(
+                f"hermes send: no targets found for platform '{platform_filter}'. "
+                f"Configured: {', '.join(sorted(platforms)) or '(none)'}",
+                file=sys.stderr,
+            )
+            return _FAILURE_EXIT
+        platforms = filtered
+
+    if json_mode:
+        print(json.dumps({"platforms": platforms}, indent=2, default=str))
+        return _SUCCESS_EXIT
+
+    if not any(platforms.values()):
+        print("No messaging platforms configured or no channels discovered yet.")
+        print("Set one up with `hermes gateway setup`, or run the gateway once so")
+        print("channel discovery can populate ~/.hermes/channel_directory.json.")
+        return _SUCCESS_EXIT
+
+    # Human display — when unfiltered, reuse the shared formatter the agent
+    # already sees. When filtered, build a minimal view ourselves.
+    if platform_filter is None:
+        print(format_directory_for_display())
+        return _SUCCESS_EXIT
+
+    for plat_name in sorted(platforms):
+        channels = platforms[plat_name]
+        print(f"{plat_name}:")
+        if not channels:
+            print("  (no channels discovered yet)")
+            continue
+        for ch in channels:
+            name = ch.get("name", "?")
+            chat_id = ch.get("id") or ch.get("chat_id") or ""
+            suffix = f"  [{chat_id}]" if chat_id and chat_id != name else ""
+            print(f"  {plat_name}:{name}{suffix}")
+        print()
+
+    return _SUCCESS_EXIT
+
+
+def _load_hermes_env() -> None:
+    """Populate ``os.environ`` from ``~/.hermes/.env`` AND bridge top-level
+    ``config.yaml`` keys into the environment so the underlying gateway
+    config loader sees platform credentials and home channel IDs.
+
+    ``send_message_tool`` reads tokens and home-channel IDs via
+    ``os.getenv(...)`` on each call. The gateway process does two things at
+    startup that ``hermes send`` must replicate when invoked standalone:
+
+    1. ``load_dotenv(~/.hermes/.env)`` — brings bot tokens into the env.
+    2. Bridge top-level simple values from ``~/.hermes/config.yaml`` into
+       ``os.environ`` (without overriding existing env vars). This is where
+       ``TELEGRAM_HOME_CHANNEL`` and friends live when the user saved them
+       via ``hermes config set``.
+
+    See ``gateway/run.py`` for the canonical version of this bridge — we
+    intentionally reimplement the minimum needed here so ``hermes send``
+    doesn't pull in the full gateway module just to resolve a home channel.
+    """
+    # Step 1: dotenv
+    try:
+        from dotenv import load_dotenv
+    except Exception:
+        load_dotenv = None  # type: ignore[assignment]
+
+    try:
+        from hermes_cli.config import get_hermes_home
+        home = get_hermes_home()
+    except Exception:
+        return
+
+    env_path = home / ".env"
+    if load_dotenv and env_path.exists():
+        try:
+            load_dotenv(str(env_path), override=True, encoding="utf-8")
+        except UnicodeDecodeError:
+            try:
+                load_dotenv(str(env_path), override=True, encoding="latin-1")
+            except Exception:
+                pass
+        except Exception:
+            pass
+
+    # Step 2: bridge top-level config.yaml values into the environment so
+    # gateway.config.load_gateway_config() sees them. Scalars only; don't
+    # override values already in the env.
+    import os
+    config_path = home / "config.yaml"
+    if not config_path.exists():
+        return
+
+    try:
+        import yaml  # type: ignore[import-not-found]
+    except Exception:
+        return
+
+    try:
+        with open(config_path, "r", encoding="utf-8") as fh:
+            raw = yaml.safe_load(fh) or {}
+    except Exception:
+        return
+
+    try:
+        from hermes_cli.config import _expand_env_vars
+        raw = _expand_env_vars(raw)
+    except Exception:
+        pass
+
+    if not isinstance(raw, dict):
+        return
+
+    for key, val in raw.items():
+        if not isinstance(val, (str, int, float, bool)):
+            continue
+        if key in os.environ:
+            continue
+        os.environ[key] = str(val)
+
+
+def cmd_send(args: argparse.Namespace) -> None:
+    """Entry point wired into the top-level argparse dispatcher."""
+
+    # Bridge ~/.hermes/.env and ~/.hermes/config.yaml into os.environ so the
+    # gateway config loader (invoked downstream by send_message_tool and by
+    # the channel directory) can see platform credentials and home channels.
+    _load_hermes_env()
+
+    # --list short-circuits everything else.
+    if getattr(args, "list_targets", False):
+        # When `--list telegram` is used, argparse stores "telegram" in the
+        # `message` positional (since list_targets takes no argument).
+        platform_filter = getattr(args, "message", None)
+        exit_code = _list_targets(platform_filter, json_mode=getattr(args, "json", False))
+        sys.exit(exit_code)
+
+    target = _resolve_target(getattr(args, "to", None))
+    if not target:
+        print(
+            "hermes send: --to PLATFORM[:channel[:thread]] is required\n"
+            "Examples:\n"
+            "  hermes send --to telegram \"hello\"\n"
+            "  hermes send --to discord:#ops --file report.md\n"
+            "  hermes send --list      # list available targets",
+            file=sys.stderr,
+        )
+        sys.exit(_USAGE_EXIT)
+
+    message = _read_message_body(
+        getattr(args, "message", None),
+        getattr(args, "file", None),
+    )
+    if message is None or not message.strip():
+        print(
+            "hermes send: no message provided. Pass text as a positional "
+            "argument, use --file PATH, or pipe data via stdin.",
+            file=sys.stderr,
+        )
+        sys.exit(_USAGE_EXIT)
+
+    # Optional: prepend a subject line. Useful for alerting scripts that
+    # want a consistent header without inlining it into every call.
+    subject = getattr(args, "subject", None)
+    if subject:
+        message = f"{subject}\n\n{message.lstrip()}"
+
+    # Import lazily so `hermes send --help` stays fast and does not pull in
+    # the full tool registry / gateway config stack.
+    from tools.send_message_tool import send_message_tool
+
+    # send_message_tool auto-loads gateway config + env and routes to the
+    # appropriate platform adapter (bot-token path for Telegram/Discord/Slack/
+    # Signal/SMS/WhatsApp; live-adapter path for plugin platforms).
+    #
+    # It expects the standard tool-call dict and returns a JSON string.
+    tool_args = {
+        "action": "send",
+        "target": target,
+        "message": message,
+    }
+
+    result = send_message_tool(tool_args)
+    exit_code = _emit_result(
+        result,
+        json_mode=getattr(args, "json", False),
+        quiet=getattr(args, "quiet", False),
+    )
+    sys.exit(exit_code)
+
+
+def register_send_subparser(subparsers) -> argparse.ArgumentParser:
+    """Create the ``send`` subparser and return it.
+
+    Kept as a standalone function so the top-level parser builder can wire
+    it in next to the other messaging subcommands without cluttering
+    ``_parser.py`` or ``main.py``.
+    """
+    parser = subparsers.add_parser(
+        "send",
+        help="Send a message to a configured platform (scripts, cron jobs, CI).",
+        description=(
+            "Pipe text from any shell script to any messaging platform Hermes "
+            "is already configured for. Reuses the gateway's platform "
+            "credentials (~/.hermes/.env + ~/.hermes/config.yaml) — no LLM, "
+            "no agent loop, no running gateway required for bot-token "
+            "platforms like Telegram/Discord/Slack/Signal."
+        ),
+        epilog=(
+            "Examples:\n"
+            "  hermes send --to telegram \"deploy finished\"\n"
+            "  echo \"RAM 92%\" | hermes send --to telegram:-1001234567890\n"
+            "  hermes send --to discord:#ops --file /tmp/report.md\n"
+            "  hermes send --to slack:#eng --subject \"[CI]\" --file build.log\n"
+            "  hermes send --list                  # all platforms\n"
+            "  hermes send --list telegram         # filter by platform\n"
+            "\n"
+            "Exit codes: 0 ok, 1 delivery/backend error, 2 usage error."
+        ),
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+
+    parser.add_argument(
+        "-t",
+        "--to",
+        metavar="TARGET",
+        default=None,
+        help=(
+            "Delivery target. Format: 'platform' (home channel), "
+            "'platform:chat_id', 'platform:chat_id:thread_id', or "
+            "'platform:#channel-name'. Examples: telegram, "
+            "telegram:-1001234567890:17585, discord:#ops, slack:C0123ABCD, "
+            "signal:+15551234567."
+        ),
+    )
+
+    parser.add_argument(
+        "message",
+        nargs="?",
+        default=None,
+        help="Message text. If omitted, read from --file or stdin.",
+    )
+
+    # Legacy / convenience positional removed — use --to for clarity.
+
+    parser.add_argument(
+        "-f",
+        "--file",
+        metavar="PATH",
+        default=None,
+        help="Read message body from PATH. Use '-' to force stdin.",
+    )
+
+    parser.add_argument(
+        "-s",
+        "--subject",
+        metavar="LINE",
+        default=None,
+        help="Prepend a subject/header line before the message body.",
+    )
+
+    parser.add_argument(
+        "-l",
+        "--list",
+        dest="list_targets",
+        action="store_true",
+        default=False,
+        help="List available targets. Optional positional filter: `hermes send --list telegram`.",
+    )
+
+    parser.add_argument(
+        "-q",
+        "--quiet",
+        action="store_true",
+        default=False,
+        help="Suppress stdout on success (exit code only).",
+    )
+
+    parser.add_argument(
+        "--json",
+        action="store_true",
+        default=False,
+        help="Emit raw JSON result instead of human-readable output.",
+    )
+
+    parser.set_defaults(func=cmd_send)
+    return parser
+
+
+__all__ = ["cmd_send", "register_send_subparser"]