diff --git a/docs/how-to/4_Use_abstract_instrument_server.md b/docs/how-to/4_Use_abstract_instrument_server.md
index 3fdd2dfb..907e143b 100644
--- a/docs/how-to/4_Use_abstract_instrument_server.md
+++ b/docs/how-to/4_Use_abstract_instrument_server.md
@@ -34,6 +34,7 @@ Commands must be newline-terminated.
 | `connect_hardware`| None | Re-establishes connection to hardware server. |
 | `disconnect_hardware`| None | Safely disconnects from hardware. |
 | `shutdown` | None | Stops the server and disconnects hardware. |
+| `command_list` | None | Return a list of available commands. |
 
 
 ## Implementation Guide
diff --git a/docs/how-to/4c_pulse_genertor_shanghai_tech.md b/docs/how-to/4c_pulse_genertor_shanghai_tech.md
index 514d9368..1b821412 100644
--- a/docs/how-to/4c_pulse_genertor_shanghai_tech.md
+++ b/docs/how-to/4c_pulse_genertor_shanghai_tech.md
@@ -39,6 +39,7 @@ The server follows a **Request-Response** model. Every command sent by a client
 | `get_delay` | None | Queries the current delay from hardware. | `get_delay\n` |
 | `reset_serial_buffer`| None | Clears the hardware's internal I/O buffers. | `reset_serial_buffer\n` |
 | `pass_command` | `string` | Sends a raw AT command to the device. | `pass_command\tAT+VER\n` |
+| `command_list` | None | Return a list of available commands. |
 | `shutdown` | None | Safely stops the server and releases hardware. | `shutdown\n` |
 
 ---
diff --git a/docs/how-to/5_cli_documentation.md b/docs/how-to/5_cli_documentation.md
new file mode 100644
index 00000000..91fbd852
--- /dev/null
+++ b/docs/how-to/5_cli_documentation.md
@@ -0,0 +1,62 @@
+# 📟sm-bluesky CLI Reference
+
+The `sm-bluesky` command-line interface provides tools to launch instrument servers and interact with running instances via quick payloads (commands).
+
+---
+
+## 🚀 Commands Overview
+
+The interface is split into two primary modes:
+* **`start`**: Configures and spins up background hardware device server.
+* **`send`**: A lightweight diagnostic utility to send arbitrary string payloads to an active server.
+
+For extra information use:
+* **`-h`, `--help`**: Displays general or command-specific help menus.
+* **`-v`, `--version`**: Displays the currently installed package version of `sm-bluesky`.
+---
+
+## 🛠️ Detailed Usage
+
+### 1. Starting an Instrument Server
+Launches a dedicated hardware communication server. By default, it listens on all available interfaces (`0.0.0.0`) to ensure remote beamline workstations can reach the server.
+
+```bash
+sm-bluesky start sh_pulse_generator [FLAGS]
+```
+| Flag   | Type | Default | Description| 
+| -----  | -----| ------  | -----------| 
+| --host | str  | 0.0.0.0 | Binding host network address.| 
+| --port | int | 7891 | TCP port boundary for socket listening. | 
+| --ipv6 | bool | None | Flags the socket to use IPv6 dual-stack addressing. | 
+
+### sh_pulse_generator Specific FlAG
+
+| Flag   | Type | Default | Description| 
+| -----  | -----| ------  | -----------| 
+| --usb-port | str | COM4 | Target serial/USB backend port identifier. | 
+| --baud-rate | int | 9600 | Serial connection baud rate. | 
+| --timeout | float | 1.0 | Read/write timeout duration in seconds. | 
+| --max-pulse-delay | int | 1024 | Boundary constraints for safe pulse adjustments. | 
+```bash
+sm-bluesky start sh_pulse_generator --usb-port COM9 --port 8080
+```
+
+### 2. Sending Payloads (Commands)
+
+Sends a single string payload directly to an active server. It defaults to the local loopback address (127.0.0.1) to ensure accidental commands don't interact with external instruments.
+```bash
+sm-bluesky send "PAYLOAD" [FLAGS]
+```
+
+| Flag | Type | Default | Description | 
+| -----| -----| ------  | -----------| 
+| --host | str | 127.0.0.1 | Target server network address.| 
+| --port | int | 7891 | Target server TCP communications port.| 
+| --timeout | float | 2.0 | Connection timeout duration in seconds.| 
+
+```bash
+# Verify status locally
+sm-bluesky send "command_list"
+
+# Adjust settings on a remote beamline server
+sm-bluesky send "SET_DELAY 512" --host 192.168.1.50 --port 7891```
diff --git a/src/sm_bluesky/__main__.py b/src/sm_bluesky/__main__.py
index 06b7fbeb..9123b385 100644
--- a/src/sm_bluesky/__main__.py
+++ b/src/sm_bluesky/__main__.py
@@ -1,24 +1,6 @@
 """Interface for ``python -m sm_bluesky``."""
 
-from argparse import ArgumentParser
-from collections.abc import Sequence
-
-from . import __version__
-
-__all__ = ["main"]
-
-
-def main(args: Sequence[str] | None = None) -> None:
-    """Argument parser for the CLI."""
-    parser = ArgumentParser()
-    parser.add_argument(
-        "-v",
-        "--version",
-        action="version",
-        version=__version__,
-    )
-    parser.parse_args(args)
-
+from sm_bluesky.common.cli import main
 
 if __name__ == "__main__":
     main()
diff --git a/src/sm_bluesky/common/cli.py b/src/sm_bluesky/common/cli.py
new file mode 100644
index 00000000..93eb12d4
--- /dev/null
+++ b/src/sm_bluesky/common/cli.py
@@ -0,0 +1,131 @@
+from argparse import ArgumentParser
+from collections.abc import Sequence
+
+from sm_bluesky import __version__
+
+__all__ = ["main"]
+
+
+def main(args: Sequence[str] | None = None) -> None:
+    """Argument parser for the CLI."""
+    parser = ArgumentParser(description="sm-bluesky CLI")
+    parser.add_argument(
+        "-v",
+        "--version",
+        action="version",
+        version=__version__,
+    )
+
+    subparsers = parser.add_subparsers(dest="command", help="Commands")
+
+    # ----------------- start command ----------------------------------------------
+    start_parser = subparsers.add_parser(
+        "start",
+        help="Start an instrument server",
+        epilog="Example usage:\n  sm-bluesky start sh_pulse_generator --usb-port COM4 "
+        "--host 192.168.1.88 --port 7891 ",
+    )
+    server_subparsers = start_parser.add_subparsers(
+        dest="server_type", help="Server types"
+    )
+
+    # --- config for shanghaiTech pulse generator ---
+    sh_parser = server_subparsers.add_parser(
+        "sh_pulse_generator", help="Launch ShanghaiTech pulse Generator Server"
+    )
+    sh_parser.add_argument(
+        "--host", type=str, default="0.0.0.0", help="Binding host IP"
+    )
+    sh_parser.add_argument("--port", type=int, default=7891, help="TCP Port")
+    sh_parser.add_argument("--ipv6", action="store_true", help="Enable IPv6 support")
+    sh_parser.add_argument(
+        "--usb-port", type=str, default="COM4", help="Serial USB COM port"
+    )
+    sh_parser.add_argument(
+        "--baud-rate", type=int, default=9600, help="Serial Baud rate"
+    )
+    sh_parser.add_argument(
+        "--timeout", type=float, default=1.0, help="Serial timeout duration"
+    )
+    sh_parser.add_argument(
+        "--max-pulse-delay",
+        type=int,
+        default=1024,
+        help="Max pulse delay configuration",
+    )
+
+    # ----------------- send command ----------------------------------------------
+    """Quick command line to interact with server """
+    send_parser = subparsers.add_parser(
+        "send",
+        help="Send a single text command to a running server",
+        epilog='Example usage:\n  sm-bluesky send "SET_DELAY 512" --host 192.168.1.88'
+        " --port 8888",
+    )
+    send_parser.add_argument(
+        "payload",
+        type=str,
+        help='The command and arguments to send (e.g."SET_DELAY 512" or '
+        '"command_list")',
+    )
+    send_parser.add_argument(
+        "--host", type=str, default="127.0.0.1", help="Target server IP"
+    )
+    send_parser.add_argument(
+        "--port", type=int, default=7891, help="Target server TCP port"
+    )
+    send_parser.add_argument(
+        "--timeout", type=float, default=2.0, help="Socket timeout"
+    )
+
+    parsed_args = parser.parse_args(args)
+
+    if parsed_args.command == "start":
+        if parsed_args.server_type == "sh_pulse_generator":
+            from sm_bluesky.common.servers import GeneratorServerShanghaiTech
+
+            print(
+                f"🚀 Initializing ShanghaiTech Generator on {parsed_args.usb_port}..."
+            )
+            server = GeneratorServerShanghaiTech(
+                host=parsed_args.host,
+                port=parsed_args.port,
+                ipv6=parsed_args.ipv6,
+                usb_port=parsed_args.usb_port,
+                baud_rate=parsed_args.baud_rate,
+                timeout=parsed_args.timeout,
+                max_pulse_delay=parsed_args.max_pulse_delay,
+            )
+            try:
+                server.start()
+            except KeyboardInterrupt:
+                print("\nStopping server ...")
+                server.stop()
+        else:
+            start_parser.print_help()
+    elif parsed_args.command == "send":
+        from sm_bluesky.common.client import InstrumentClient
+
+        print(
+            f"Sending command:{parsed_args.payload} to {parsed_args.host}:"
+            + f"{parsed_args.port}"
+        )
+        try:
+            parts = parsed_args.payload.split()
+            if not parts:
+                raise ValueError("Payload cannot be empty")
+
+            command = parts[0]
+            arguments = parts[1:]
+            client = InstrumentClient(
+                host=parsed_args.host,
+                port=parsed_args.port,
+                timeout=parsed_args.timeout,
+            )
+
+            result = client.send_payload(command, *arguments)
+            print(f"✅ SUCCESS: {result}" if result else "✅ SUCCESS")
+        except Exception as err:
+            print(f"\u274c FAILED: {err}")
+    else:
+        parser.print_help()
diff --git a/src/sm_bluesky/common/client/__init__.py b/src/sm_bluesky/common/client/__init__.py
new file mode 100644
index 00000000..8cd0443b
--- /dev/null
+++ b/src/sm_bluesky/common/client/__init__.py
@@ -0,0 +1,3 @@
+from .client import InstrumentClient
+
+__all__ = ["InstrumentClient"]
diff --git a/src/sm_bluesky/common/client/client.py b/src/sm_bluesky/common/client/client.py
new file mode 100644
index 00000000..46b13a45
--- /dev/null
+++ b/src/sm_bluesky/common/client/client.py
@@ -0,0 +1,48 @@
+import socket
+
+
+class InstrumentClient:
+    """A lightweight, TCP client for interacting with AbstractInstrumentServers."""
+
+    def __init__(self, host: str = "127.0.0.1", port: int = 7891, timeout: float = 2.0):
+        self.host = host
+        self.port = port
+        self.timeout = timeout
+
+    def send_payload(self, command: str, *args: str | int | float) -> str:
+        """Sends a command to the server, returns the stripped text message data."""
+
+        payload_parts = [command] + [str(arg) for arg in args]
+        payload = "\t".join(payload_parts)
+
+        if not payload.endswith("\n"):
+            payload += "\n"
+
+        try:
+            with socket.create_connection(
+                (self.host, self.port), timeout=self.timeout
+            ) as s:
+                s.sendall(payload.encode("utf-8"))
+
+                with s.makefile("r", encoding="utf-8", errors="strict") as reader:
+                    response_line = reader.readline()
+
+                if not response_line:
+                    raise ConnectionError(
+                        "Server closed connection without returning data."
+                    )
+
+                response = response_line.strip()
+
+                if "\t" in response:
+                    status, data = response.split("\t", 1)
+                else:
+                    status, data = response, ""
+
+                if status == "1":
+                    return data
+                else:
+                    raise RuntimeError(f"Server Error: {data}")
+
+        except Exception as e:
+            raise ConnectionError(f"Communication layer failure: {e}") from e
diff --git a/src/sm_bluesky/common/server/__init__.py b/src/sm_bluesky/common/servers/__init__.py
similarity index 100%
rename from src/sm_bluesky/common/server/__init__.py
rename to src/sm_bluesky/common/servers/__init__.py
diff --git a/src/sm_bluesky/common/server/abstract_instrument_server.py b/src/sm_bluesky/common/servers/abstract_instrument_server.py
similarity index 100%
rename from src/sm_bluesky/common/server/abstract_instrument_server.py
rename to src/sm_bluesky/common/servers/abstract_instrument_server.py
diff --git a/src/sm_bluesky/common/server/pulse_generator_shanghai_tech.py b/src/sm_bluesky/common/servers/pulse_generator_shanghai_tech.py
similarity index 98%
rename from src/sm_bluesky/common/server/pulse_generator_shanghai_tech.py
rename to src/sm_bluesky/common/servers/pulse_generator_shanghai_tech.py
index b7f038c6..e852b76e 100644
--- a/src/sm_bluesky/common/server/pulse_generator_shanghai_tech.py
+++ b/src/sm_bluesky/common/servers/pulse_generator_shanghai_tech.py
@@ -2,7 +2,7 @@
 
 from serial import Serial
 
-from sm_bluesky.common.server import AbstractInstrumentServer
+from sm_bluesky.common.servers import AbstractInstrumentServer
 from sm_bluesky.log import LOGGER
 
 
diff --git a/tests/common/server/__init__.py b/tests/common/client/__init__.py
similarity index 100%
rename from tests/common/server/__init__.py
rename to tests/common/client/__init__.py
diff --git a/tests/common/client/test_client.py b/tests/common/client/test_client.py
new file mode 100644
index 00000000..52392d01
--- /dev/null
+++ b/tests/common/client/test_client.py
@@ -0,0 +1,63 @@
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from sm_bluesky.common.client import InstrumentClient
+
+
+@pytest.fixture
+def client():
+    return InstrumentClient(host="127.0.0.1", port=8888, timeout=8.0)
+
+
+@pytest.fixture
+def mock_network():
+    mock_socket = MagicMock()
+    mock_reader = MagicMock()
+
+    with (
+        patch("socket.create_connection") as mock_connect,
+        patch.object(mock_socket, "makefile") as mock_makefile,
+    ):
+        mock_connect.return_value.__enter__.return_value = mock_socket
+        mock_makefile.return_value.__enter__.return_value = mock_reader
+        yield {
+            "connect": mock_connect,
+            "socket": mock_socket,
+            "reader": mock_reader,
+        }
+
+
+def test_send_payload_success(client, mock_network):
+    mock_network["reader"].readline.return_value = "1\t512\n"
+    result = client.send_payload("SET_DELAY", 512)
+    assert result == "512"
+    mock_network["connect"].assert_called_once_with(("127.0.0.1", 8888), timeout=8.0)
+    mock_network["socket"].sendall.assert_called_once_with(b"SET_DELAY\t512\n")
+
+
+def test_send_payload_server_error(client, mock_network):
+    mock_network["reader"].readline.return_value = "0\tInvalid parameter boundary\n"
+
+    with pytest.raises(
+        ConnectionError,
+        match="Communication layer failure: Server Error: Invalid parameter boundary",
+    ):
+        client.send_payload("SET_DELAY", -999)
+
+
+def test_send_payload_network_failure(client, mock_network):
+    mock_network["connect"].create_connection.return_value = TimeoutError(
+        "Connection timed out"
+    )
+    with pytest.raises(ConnectionError, match="Communication layer failure"):
+        client.send_payload("command_list")
+
+
+def test_send_payload_empty_response(client, mock_network):
+    mock_network["reader"].readline.return_value = ""
+
+    with pytest.raises(
+        ConnectionError, match="Server closed connection without returning data."
+    ):
+        client.send_payload("PING")
diff --git a/tests/common/servers/__init__.py b/tests/common/servers/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/common/server/test_abstract_instrument_server.py b/tests/common/servers/test_abstract_instrument_server.py
similarity index 96%
rename from tests/common/server/test_abstract_instrument_server.py
rename to tests/common/servers/test_abstract_instrument_server.py
index d13cec5d..e7982cb7 100644
--- a/tests/common/server/test_abstract_instrument_server.py
+++ b/tests/common/servers/test_abstract_instrument_server.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from sm_bluesky.common.server import AbstractInstrumentServer
+from sm_bluesky.common.servers import AbstractInstrumentServer
 
 
 class MockInstrument(AbstractInstrumentServer):
@@ -25,7 +25,7 @@ def mock_socket_instance():
 def mock_instrument(mock_socket_instance: MagicMock):
 
     with patch(
-        "sm_bluesky.common.server.abstract_instrument_server.socket.socket"
+        "sm_bluesky.common.servers.abstract_instrument_server.socket.socket"
     ) as mock_socket_class:
         mock_socket_class.return_value = mock_socket_instance
         mock_instrument = MockInstrument(host="localhost", port=8888)
@@ -65,7 +65,7 @@ def test_start_handles_timeout(
 ):
     mock_socket_instance.accept.side_effect = [
         socket.timeout,
-        (MagicMock(), ("8.8.8.8", 1234)),
+        (MagicMock(), ("192.168.1.88", 1234)),
     ]
     mock_instrument._serve_client = lambda: setattr(
         mock_instrument, "_is_running", False
@@ -193,11 +193,11 @@ def test_serve_client_exception(
 
 def test_full_connection_cycle_cleanup(mock_instrument, caplog):
     mock_instance = MagicMock()
-    mock_instance.accept.return_value = (MagicMock(), ("8.8.8.8", 1234))
+    mock_instance.accept.return_value = (MagicMock(), ("192.168.1.88", 1234))
     mock_instrument._server_socket = mock_instance
 
     with patch.object(mock_instrument, "_serve_client", side_effect=None):
-        client_info = (MagicMock(), "8.8.8.8")
+        client_info = (MagicMock(), "192.168.1.88")
         with mock_instrument._manage_connection(client_info):
             pass
     client_info[0].close.assert_called_once()
diff --git a/tests/common/server/test_pulse_generator_shanghai_test.py b/tests/common/servers/test_pulse_generator_shanghai_test.py
similarity index 96%
rename from tests/common/server/test_pulse_generator_shanghai_test.py
rename to tests/common/servers/test_pulse_generator_shanghai_test.py
index 6f7c83f2..21e5c73c 100644
--- a/tests/common/server/test_pulse_generator_shanghai_test.py
+++ b/tests/common/servers/test_pulse_generator_shanghai_test.py
@@ -6,14 +6,14 @@
 import pytest
 from serial import Serial
 
-from sm_bluesky.common.server import GeneratorServerShanghaiTech
+from sm_bluesky.common.servers import GeneratorServerShanghaiTech
 
 
 @pytest.fixture
 def mock_serial():
     """Patches Serial and returns the class mock."""
     with patch(
-        "sm_bluesky.common.server.pulse_generator_shanghai_tech.Serial", spec=True
+        "sm_bluesky.common.servers.pulse_generator_shanghai_tech.Serial", spec=True
     ) as mock_serial:
         yield mock_serial
 
@@ -36,7 +36,7 @@ def test_connect_hardware_failure(
     mock_server: GeneratorServerShanghaiTech, caplog: pytest.LogCaptureFixture
 ):
     with patch(
-        "sm_bluesky.common.server.pulse_generator_shanghai_tech.Serial"
+        "sm_bluesky.common.servers.pulse_generator_shanghai_tech.Serial"
     ) as mock_serial_class:
         error_message = "Connection failed"
         mock_serial_class.side_effect = Exception(error_message)
@@ -211,7 +211,7 @@ def test_send_hardware_command_fail_no_device(mock_server: GeneratorServerShangh
 @pytest.fixture
 def running_server():
     with patch(
-        "sm_bluesky.common.server.pulse_generator_shanghai_tech.Serial"
+        "sm_bluesky.common.servers.pulse_generator_shanghai_tech.Serial"
     ) as mock_serial_class:
         mock_device = MagicMock()
         mock_serial_class.return_value = mock_device
@@ -227,7 +227,7 @@ def running_server():
         server.stop()
 
 
-def test_full_tcp_command_flow(running_server):
+def test_full_tcp_command_flow(running_server: MagicMock):
     """Client sends a command via TCP and verifies the protocol response."""
     client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     client.connect(("127.0.0.1", 9999))
diff --git a/tests/common/test_cli.py b/tests/common/test_cli.py
new file mode 100644
index 00000000..ca8c0ae7
--- /dev/null
+++ b/tests/common/test_cli.py
@@ -0,0 +1,165 @@
+import subprocess
+import sys
+from collections.abc import Generator
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from sm_bluesky import __version__
+from sm_bluesky.common.cli import main
+
+
+@pytest.fixture
+def mock_sh_generator() -> Generator[MagicMock, None, None]:
+    with patch("sm_bluesky.common.servers.GeneratorServerShanghaiTech") as mock_server:
+        yield mock_server
+
+
+@pytest.fixture
+def mock_instrument_client() -> Generator[MagicMock, None, None]:
+    with patch("sm_bluesky.common.client.InstrumentClient") as mock_client:
+        yield mock_client
+
+
+def test_cli_shanghai_tech_start_default_arguments(
+    mock_sh_generator: MagicMock,
+) -> None:
+    mock_instance = mock_sh_generator.return_value
+
+    main(["start", "sh_pulse_generator"])
+
+    mock_sh_generator.assert_called_once_with(
+        host="0.0.0.0",
+        port=7891,
+        ipv6=False,
+        usb_port="COM4",
+        baud_rate=9600,
+        timeout=1.0,
+        max_pulse_delay=1024,
+    )
+    mock_instance.start.assert_called_once()
+
+
+def test_cli_shanghai_tech_start_custom_flags(mock_sh_generator: MagicMock) -> None:
+    main(
+        [
+            "start",
+            "sh_pulse_generator",
+            "--host",
+            "127.0.0.1",
+            "--port",
+            "8080",
+            "--ipv6",
+            "--usb-port",
+            "COM9",
+            "--baud-rate",
+            "115200",
+            "--timeout",
+            "2.5",
+            "--max-pulse-delay",
+            "2048",
+        ]
+    )
+
+    mock_sh_generator.assert_called_once_with(
+        host="127.0.0.1",
+        port=8080,
+        ipv6=True,
+        usb_port="COM9",
+        baud_rate=115200,
+        timeout=2.5,
+        max_pulse_delay=2048,
+    )
+
+
+def test_cli_handles_keyboard_interrupt(mock_sh_generator: MagicMock) -> None:
+    mock_instance = mock_sh_generator.return_value
+    mock_instance.start.side_effect = KeyboardInterrupt()
+    main(["start", "sh_pulse_generator"])
+    mock_instance.stop.assert_called_once()
+
+
+@pytest.mark.parametrize(
+    "command, expected_output, look_in_stderr",
+    [
+        ([], "sm-bluesky CLI", False),
+        (
+            ["junk"],
+            "invalid choice: 'junk'",
+            True,
+        ),
+        (
+            ["start", "junk"],
+            "invalid choice: 'junk'",
+            True,
+        ),
+        (
+            ["start"],
+            "usage: ",
+            False,
+        ),
+    ],
+)
+def test_cli_shows_help_on_invalid_command(
+    command: list[str],
+    expected_output: str,
+    look_in_stderr: bool,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    if look_in_stderr:
+        with pytest.raises(SystemExit) as exc_info:
+            main(command)
+        assert exc_info.value.code == 2
+    else:
+        main(command)
+
+    captured = capsys.readouterr()
+    output = captured.err if look_in_stderr else captured.out
+
+    assert expected_output in output
+
+
+def test_cli_version():
+    cmd = [sys.executable, "-m", "sm_bluesky", "--version"]
+    assert subprocess.check_output(cmd).decode().strip() == __version__
+
+
+def test_cli_send_command_success(
+    mock_instrument_client: MagicMock, capsys: pytest.CaptureFixture[str]
+) -> None:
+    mock_instance = mock_instrument_client.return_value
+    mock_instance.send_payload.return_value = "512"
+
+    main(["send", "SET_DELAY 512", "--host", "0.0.0.0", "--port", "8888"])
+
+    mock_instrument_client.assert_called_once_with(
+        host="0.0.0.0", port=8888, timeout=2.0
+    )
+    mock_instance.send_payload.assert_called_once_with("SET_DELAY", "512")
+
+    captured = capsys.readouterr()
+    assert "Sending command:SET_DELAY 512" in captured.out
+    assert "SUCCESS: 512" in captured.out
+
+
+def test_cli_send_command_failure(
+    mock_instrument_client: MagicMock, capsys: pytest.CaptureFixture[str]
+) -> None:
+    mock_instance = mock_instrument_client.return_value
+    mock_instance.send_payload.side_effect = ConnectionError("Help help")
+
+    main(["send", "do not matter"])
+
+    captured = capsys.readouterr()
+    assert "FAILED: Help help" in captured.out
+
+
+def test_cli_send_empty_payload(
+    mock_instrument_client: MagicMock, capsys: pytest.CaptureFixture[str]
+) -> None:
+
+    main(["send", "   "])
+
+    captured = capsys.readouterr()
+    assert "FAILED: Payload cannot be empty" in captured.out
+    mock_instrument_client.assert_not_called()
diff --git a/tests/test_cli.py b/tests/test_cli.py
deleted file mode 100644
index a82937d0..00000000
--- a/tests/test_cli.py
+++ /dev/null
@@ -1,9 +0,0 @@
-import subprocess
-import sys
-
-from sm_bluesky import __version__
-
-
-def test_cli_version():
-    cmd = [sys.executable, "-m", "sm_bluesky", "--version"]
-    assert subprocess.check_output(cmd).decode().strip() == __version__