diff --git a/belay/cli/cache.py b/belay/cli/cache.py
index 1cc882be..9b80563d 100644
--- a/belay/cli/cache.py
+++ b/belay/cli/cache.py
@@ -4,30 +4,37 @@
 with contextlib.suppress(ImportError):
     import readline
 import shutil
+import sys
+from typing import Annotated
 
-import typer
-from typer import Argument, Option, Typer
+from cyclopts import App, Parameter
 
 from belay.project import find_cache_folder
 
-app = Typer(no_args_is_help=True, help="Perform action's on Belay's cache.")
+app = App(help="Perform action's on Belay's cache.")
 
 
-@app.command()
+@app.command
 def clear(
-    prefix: str = Argument("", help="Clear all caches that start with this."),
-    yes: bool = Option(
-        False,
-        "--yes",
-        "-y",
-        help='Automatically answer "yes" to all confirmation prompts.',
-    ),
-    all: bool = Option(False, "--all", "-a", help="Clear all caches."),
+    prefix: str = "",
+    *,
+    yes: Annotated[bool, Parameter(alias="-y")] = False,
+    all: Annotated[bool, Parameter(alias="-a")] = False,
 ):
-    """Clear cache."""
+    """Clear cache.
+
+    Parameters
+    ----------
+    prefix : str
+        Clear all caches that start with this.
+    yes : bool
+        Automatically answer "yes" to all confirmation prompts.
+    all : bool
+        Clear all caches.
+    """
     if (not prefix and not all) or (prefix and all):
         print('Either provide a prefix OR set the "--all" flag.')
-        raise typer.Exit()
+        sys.exit(1)
 
     cache_folder = find_cache_folder()
 
@@ -37,13 +44,15 @@ def clear(
 
     if not cache_paths:
         print(f'No caches found starting with "{prefix}"')
-        raise typer.Exit()
+        sys.exit(1)
 
     if not yes:
         print("Found caches:")
         for cache_name in cache_names:
             print(f"  • {cache_name}")
-        typer.confirm("Clear these caches?", abort=True)
+        response = input("Clear these caches? [y/N]: ")
+        if response.lower() not in ("y", "yes"):
+            sys.exit(1)
 
     for path in cache_paths:
         if path.is_file():
@@ -52,7 +61,7 @@ def clear(
             shutil.rmtree(path)
 
 
-@app.command()
+@app.command
 def list():
     """List cache elements."""
     cache_folder = find_cache_folder()
@@ -62,7 +71,7 @@ def list():
         print(item)
 
 
-@app.command()
+@app.command
 def info():
     """Display cache location and size."""
     cache_folder = find_cache_folder()
diff --git a/belay/cli/common.py b/belay/cli/common.py
index 66d7fd8b..2cf32ff6 100644
--- a/belay/cli/common.py
+++ b/belay/cli/common.py
@@ -1,16 +1,26 @@
-from belay.pyboard import PyboardException
+from contextlib import contextmanager
+from typing import Annotated
+
+from cyclopts import Parameter
 
-help_port = "Port (like /dev/ttyUSB0) or WebSocket (like ws://192.168.1.100) of device."
-help_password = "Password for communication methods (like WebREPL) that require authentication."  # nosec  # noqa: S105
+from belay.pyboard import PyboardException
 
+# Custom annotated types for consistent CLI parameter help
+PortStr = Annotated[
+    str,
+    Parameter(help="Port (like /dev/ttyUSB0) or WebSocket (like ws://192.168.1.100) of device."),
+]
+PasswordStr = Annotated[
+    str,
+    Parameter(help="Password for communication methods (like WebREPL) that require authentication."),
+]
 
-class remove_stacktrace:  # noqa: N801
-    def __enter__(self):
-        return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
-        if exc_type is not None and issubclass(exc_type, PyboardException):
-            print(exc_value)
-            return True  # suppress the full stack trace
-        else:
-            return False  # let other exceptions propagate normally
+@contextmanager
+def remove_stacktrace():
+    """Context manager that suppresses PyboardException stack traces and prints only the error message."""
+    try:
+        yield
+    except PyboardException as e:
+        print(e)
+        # Exception is handled, don't re-raise
diff --git a/belay/cli/exec.py b/belay/cli/exec.py
index 04bc6f54..873ccd56 100644
--- a/belay/cli/exec.py
+++ b/belay/cli/exec.py
@@ -1,17 +1,15 @@
-from pathlib import Path
-
-from typer import Argument, Option
-
 from belay import Device
-from belay.cli.common import help_password, help_port, remove_stacktrace
+from belay.cli.common import PasswordStr, PortStr, remove_stacktrace
+
 
+def exec(port: PortStr, statement: str, *, password: PasswordStr = ""):
+    """Execute python statement on-device.
 
-def exec(
-    port: str = Argument(..., help=help_port),
-    statement: str = Argument(..., help="Statement to execute on-device."),
-    password: str = Option("", help=help_password),
-):
-    """Execute python statement on-device."""
+    Parameters
+    ----------
+    statement : str
+        Statement to execute on-device.
+    """
     device = Device(port, password=password)
     with remove_stacktrace():
         device(statement)
diff --git a/belay/cli/info.py b/belay/cli/info.py
index 889c17fc..eb8adede 100644
--- a/belay/cli/info.py
+++ b/belay/cli/info.py
@@ -1,13 +1,8 @@
-from typer import Argument, Option
-
 from belay import Device
-from belay.cli.common import help_password, help_port
+from belay.cli.common import PasswordStr, PortStr
 
 
-def info(
-    port: str = Argument(..., help=help_port),
-    password: str = Option("", help=help_password),
-):
+def info(port: PortStr, *, password: PasswordStr = ""):
     """Display device firmware information."""
     device = Device(port, password=password)
     version_str = "v" + ".".join(str(x) for x in device.implementation.version)
diff --git a/belay/cli/install.py b/belay/cli/install.py
index 71ce440d..6c669078 100644
--- a/belay/cli/install.py
+++ b/belay/cli/install.py
@@ -2,27 +2,43 @@
 from functools import partial
 from pathlib import Path
 from tempfile import TemporaryDirectory
-from typing import List, Optional
+from typing import Annotated, Optional
 
+from cyclopts import Parameter
 from rich.progress import Progress
-from typer import Argument, Option
 
 from belay import Device
-from belay.cli.common import help_password, help_port, remove_stacktrace
+from belay.cli.common import PasswordStr, PortStr, remove_stacktrace
 from belay.cli.sync import sync_device as _sync_device
 from belay.project import find_project_folder, load_groups, load_pyproject
 
 
 def install(
-    port: str = Argument(..., help=help_port),
-    password: str = Option("", help=help_password),
-    mpy_cross_binary: Optional[Path] = Option(None, help="Compile py files with this executable."),
-    run: Optional[Path] = Option(None, help="Run script on-device after installing."),
-    main: Optional[Path] = Option(None, help="Sync script to /main.py after installing."),
-    with_groups: List[str] = Option(None, "--with", help="Include specified optional dependency group."),
-    follow: bool = Option(False, "--follow", "-f", help="Follow the stdout after upload."),
+    port: PortStr,
+    *,
+    password: PasswordStr = "",
+    mpy_cross_binary: Optional[Path] = None,
+    run: Optional[Path] = None,
+    main: Optional[Path] = None,
+    with_groups: Annotated[Optional[list[str]], Parameter(name="--with")] = None,
+    follow: Annotated[bool, Parameter(alias="-f")] = False,
 ):
-    """Sync dependencies and project itself to device."""
+    """Sync dependencies and project itself to device.
+
+    Parameters
+    ----------
+    mpy_cross_binary : Optional[Path]
+        Compile py files with this executable.
+    run : Optional[Path]
+        Run script on-device after installing.
+    main : Optional[Path]
+        Sync script to /main.py after installing.
+    with_groups : Optional[list[str]]
+        Include specified optional dependency group.
+    follow : bool
+        Follow the stdout after upload.
+    """
+    with_groups = with_groups or []
     if run and run.suffix != ".py":
         raise ValueError("Run script MUST be a python file.")
     if main and main.suffix != ".py":
@@ -94,7 +110,7 @@ def progress_update(description=None, **kwargs):
                 device(content)
             return
 
-        # Reset device so ``main.py`` has a chance to execute.
+        # Reset device so `main.py` has a chance to execute.
         device.soft_reset()
         if follow:
             device.terminal()
diff --git a/belay/cli/main.py b/belay/cli/main.py
index acfcff1a..be2ba607 100644
--- a/belay/cli/main.py
+++ b/belay/cli/main.py
@@ -3,13 +3,12 @@
 import subprocess  # nosec
 import sys
 from tempfile import TemporaryDirectory
-from typing import List
+from typing import Annotated
 
-import typer
-from typer import Option
+from cyclopts import App, Parameter
 
 import belay
-from belay.cli import cache
+from belay.cli.cache import app as cache_app
 from belay.cli.clean import clean
 from belay.cli.exec import exec
 from belay.cli.info import info
@@ -22,28 +21,27 @@
 from belay.cli.update import update
 from belay.project import load_groups
 
-app = typer.Typer(no_args_is_help=True, pretty_exceptions_enable=False)
-app.add_typer(cache.app, name="cache")
-
-app.command()(clean)
-app.command()(exec)
-app.command()(info)
-app.command()(install)
-app.command()(new)
-app.command()(run)
-app.command()(select)
-app.command()(sync)
-app.command()(terminal)
-app.command()(update)
-
-
-def run_exec(command: List[str]):
+app = App(version_flags=("--version", "-v"), help_format="markdown")
+app.command(cache_app, name="cache")
+app.command(clean)
+app.command(exec)
+app.command(info)
+app.command(install)
+app.command(new)
+app.command(run)
+app.command(select)
+app.command(sync)
+app.command(terminal)
+app.command(update)
+
+
+def run_exec(command: list[str]):
     """Enable virtual-environment and run command."""
     groups = load_groups()
     virtual_env = os.environ.copy()
     # Add all dependency groups to the micropython path.
     # This flattens all dependencies to a single folder and fetches fresh
-    # copies of dependencies in ``develop`` mode.
+    # copies of dependencies in `develop` mode.
     with TemporaryDirectory() as tmp_dir:
         virtual_env["MICROPYPATH"] = f".:{tmp_dir}"
         for group in groups:
@@ -67,38 +65,17 @@ def _get(indexable, index, default=None):
 
 
 def run_app(*args, **kwargs):
-    """Add CLI hacks that are not Typer-friendly here."""
+    """Add CLI hacks that are not Cyclopts-friendly here."""
     command = _get(sys.argv, 1)
-
-    try:
-        exec_path = shutil.which(sys.argv[2])
-    except IndexError:
-        exec_path = None
-
-    if command == "run" and exec_path:
-        # Special subcommand override.
-        run_exec(sys.argv[2:])
+    if command == "run":
+        try:
+            exec_path = shutil.which(sys.argv[2])
+        except IndexError:
+            exec_path = None
+        if exec_path is not None:
+            run_exec(sys.argv[2:])
+        else:
+            app(*args, **kwargs)
     else:
-        # Common-case; use Typer functionality.
+        # Common-case; use Cyclopts functionality.
         app(*args, **kwargs)
-
-
-def version_callback(value: bool):
-    if not value:
-        return
-    print(belay.__version__)
-    raise typer.Exit()
-
-
-@app.callback()
-def common(
-    ctx: typer.Context,
-    version: bool = Option(
-        None,
-        "--version",
-        "-v",
-        callback=version_callback,
-        help="Display Belay's version.",
-    ),
-):
-    pass
diff --git a/belay/cli/new.py b/belay/cli/new.py
index 6d95c525..4da8b17b 100644
--- a/belay/cli/new.py
+++ b/belay/cli/new.py
@@ -1,19 +1,19 @@
+import importlib.resources as importlib_resources
 import re
 import shutil
-import sys
 from pathlib import Path
 
 from packaging.utils import canonicalize_name
-from typer import Argument
 
-if sys.version_info < (3, 9, 0):
-    import importlib_resources
-else:
-    import importlib.resources as importlib_resources
 
+def new(project_name: str):
+    """Create a new micropython project structure.
 
-def new(project_name: str = Argument(..., help="Project Name.")):
-    """Create a new micropython project structure."""
+    Parameters
+    ----------
+    project_name : str
+        Project Name.
+    """
     package_name = canonicalize_name(project_name)
     dst_dir = Path() / project_name
     template_dir = importlib_resources.files("belay") / "cli" / "new_template"
diff --git a/belay/cli/questionary_ext.py b/belay/cli/questionary_ext.py
index 85224175..d0bef7e2 100644
--- a/belay/cli/questionary_ext.py
+++ b/belay/cli/questionary_ext.py
@@ -1,8 +1,7 @@
-from typing import Any, Dict, Optional, Sequence, Union
+from collections.abc import Sequence
+from typing import Any, Optional, Union
 
-from prompt_toolkit import PromptSession
 from prompt_toolkit.application import Application
-from prompt_toolkit.formatted_text import to_formatted_text
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit.keys import Keys
 from prompt_toolkit.styles import Style, merge_styles
@@ -17,51 +16,11 @@
 from questionary.question import Question
 
 
-def press_any_key_to_continue(
-    message: str = "Press any key to continue...",
-    style: Optional[Style] = None,
-    **kwargs,
-):
-    """Wait until user presses any key to continue.
-
-    Example:
-        >>> import questionary
-        >>> questionary.press_any_key_to_continue().ask()
-         Press any key to continue...
-        None
-
-    Args:
-        message: Question text.
-
-        style: A custom color and style for the question parts. You can
-               configure colors as well as font types for different elements.
-    """
-    merged_style = merge_styles([DEFAULT_STYLE, style])
-
-    def get_prompt_tokens():
-        tokens = []
-
-        tokens.append(("class:question", f" {message} "))
-
-        return to_formatted_text(tokens)
-
-    def exit_with_result(event):
-        event.app.exit(result=None)
-
-    bindings = KeyBindings()
-
-    @bindings.add(Keys.Any)
-    def any_key(event):
-        exit_with_result(event)
-
-    return Question(PromptSession(get_prompt_tokens, key_bindings=bindings, style=merged_style, **kwargs).app)
-
-
 def select_table(
     message: str,
     header: str,
-    choices: Sequence[Union[str, Choice, Dict[str, Any]]],
-    default: Optional[Union[str, Choice, Dict[str, Any]]] = None,
+    choices: Sequence[Union[str, Choice, dict[str, Any]]],
+    default: Optional[Union[str, Choice, dict[str, Any]]] = None,
     qmark: str = DEFAULT_QUESTION_PREFIX,
     pointer: Optional[str] = DEFAULT_SELECTED_POINTER,
     style: Optional[Style] = None,
@@ -75,17 +34,17 @@ def select_table(
     Args:
         message: Question text
         header: Table header text
-        choices: Items shown in the selection, this can contain :class:`Choice` or
-                 or :class:`Separator` objects or simple items as strings. Passing
-                 :class:`Choice` objects, allows you to configure the item more
+        choices: Items shown in the selection, this can contain `Choice` or
+                 or `Separator` objects or simple items as strings. Passing
+                 `Choice` objects, allows you to configure the item more
                  (e.g. preselecting it or disabling it).
         default: A value corresponding to a selectable item in the choices,
                  to initially set the pointer position to.
         qmark: Question prefix displayed in front of the question.
-               By default this is a ``?``.
+               By default this is a `?`.
         pointer: Pointer symbol in front of the currently highlighted element.
-                 By default this is a ``»``.
-                 Use ``None`` to disable it.
+                 By default this is a `»`.
+                 Use `None` to disable it.
         style: A custom color and style for the question parts. You can
                configure colors as well as font types for different elements.
         use_indicator: Flag to enable the small indicator in front of the
@@ -94,7 +53,7 @@ def select_table(
 
     Returns
     -------
-        :class:`Question`: Question instance, ready to be prompted (using ``.ask()``).
+        Question instance, ready to be prompted (using `.ask()`).
     """
     if choices is None or len(choices) == 0:
         raise ValueError("A list of choices needs to be provided.")
diff --git a/belay/cli/run.py b/belay/cli/run.py
index e096912a..dbc4e155 100644
--- a/belay/cli/run.py
+++ b/belay/cli/run.py
@@ -1,26 +1,26 @@
 from pathlib import Path
 
-from typer import Argument, Option
-
 from belay import Device
-from belay.cli.common import help_password, help_port, remove_stacktrace
+from belay.cli.common import PasswordStr, PortStr, remove_stacktrace
 
 
-def run(
-    port: str = Argument(..., help=help_port),
-    file: Path = Argument(..., help="File to run on-device."),
-    password: str = Option("", help=help_password),
-):
+def run(port: PortStr, file: Path, *, password: PasswordStr = ""):
     """Run file on-device.
 
-    If the first argument, ``port``, is resolvable to an executable,
+    If the first argument, `port`, is resolvable to an executable,
     the remainder of the command will be interpreted as a shell command
     that will be executed in a pseudo-micropython-virtual-environment.
-    As of right now, this just sets ``MICROPYPATH`` to all of the dependency
-    groups' folders. E.g::
+    As of right now, this just sets `MICROPYPATH` to all of the dependency
+    groups' folders. E.g:
 
-            belay run micropython -m unittest
+    ```bash
+    belay run micropython -m unittest
+    ```
 
+    Parameters
+    ----------
+    file : Path
+        File to run on-device.
     """
     content = file.read_text(encoding="utf-8")
     with Device(port, password=password) as device, remove_stacktrace():
diff --git a/belay/cli/select.py b/belay/cli/select.py
index a05c622d..7f79b763 100644
--- a/belay/cli/select.py
+++ b/belay/cli/select.py
@@ -1,12 +1,12 @@
 import asyncio
 import contextlib
+import sys
 
 import questionary
-import typer
 from questionary import Choice
 
 from belay import Device, DeviceMeta
-from belay.cli.questionary_ext import press_any_key_to_continue, select_table
+from belay.cli.questionary_ext import select_table
 from belay.usb_specifier import list_devices
 
 
@@ -20,7 +20,7 @@ async def blink_loop(device):
 
 async def blink_until_prompt(device):
     blink_task = asyncio.create_task(blink_loop(device))
-    await press_any_key_to_continue().ask_async()
+    await questionary.press_any_key_to_continue().ask_async()
     blink_task.cancel()
     with contextlib.suppress(asyncio.CancelledError):
         await blink_task
@@ -117,7 +117,7 @@ def select():
 
     if not choices:
         print("Detected no devices.")
-        raise typer.Exit(code=1)
+        sys.exit(1)
 
     device_index = select_table(
         "Select USB Device (Use arrow keys):",
diff --git a/belay/cli/sync.py b/belay/cli/sync.py
index bee405d1..febd10cd 100644
--- a/belay/cli/sync.py
+++ b/belay/cli/sync.py
@@ -1,13 +1,11 @@
-from contextlib import nullcontext
 from functools import partial
 from pathlib import Path
-from typing import List, Optional
+from typing import Optional
 
 from rich.progress import Progress
-from typer import Argument, Option
 
 from belay import Device
-from belay.cli.common import help_password, help_port
+from belay.cli.common import PasswordStr, PortStr
 
 
 def sync_device(device, folder, progress_update, **kwargs):
@@ -16,19 +14,30 @@ def sync_device(device, folder, progress_update, **kwargs):
 
 
 def sync(
-    port: str = Argument(..., help=help_port),
-    folder: Path = Argument(..., help="Path of local file or folder to sync."),
-    dst: str = Option("/", help="Destination directory to unpack folder contents to."),
-    password: str = Option("", help=help_password),
-    keep: Optional[List[str]] = Option(None, help="Files to keep."),
-    ignore: Optional[List[str]] = Option(None, help="Files to ignore."),
-    mpy_cross_binary: Optional[Path] = Option(None, help="Compile py files with this executable."),
+    port: PortStr,
+    folder: Path,
+    *,
+    dst: str = "/",
+    password: PasswordStr = "",
+    keep: Optional[list[str]] = None,
+    ignore: Optional[list[str]] = None,
+    mpy_cross_binary: Optional[Path] = None,
 ):
-    """Synchronize a folder to device."""
-    # Typer issues: https://github.com/tiangolo/typer/issues/410
-    keep = keep if keep else None
-    ignore = ignore if ignore else None
-
+    """Synchronize a folder to device.
+
+    Parameters
+    ----------
+    folder : Path
+        Path of local file or folder to sync.
+    dst : str
+        Destination directory to unpack folder contents to.
+    keep : Optional[list[str]]
+        Files to keep.
+    ignore : Optional[list[str]]
+        Files to ignore.
+    mpy_cross_binary : Optional[Path]
+        Compile py files with this executable.
+    """
     with Device(port, password=password) as device, Progress() as progress:
         task_id = progress.add_task("")
 
diff --git a/belay/cli/terminal.py b/belay/cli/terminal.py
index 7be0768d..1e944ee4 100644
--- a/belay/cli/terminal.py
+++ b/belay/cli/terminal.py
@@ -1,13 +1,8 @@
-from typer import Argument, Option
-
 from belay import Device
-from belay.cli.common import help_password, help_port
+from belay.cli.common import PasswordStr, PortStr
 
 
-def terminal(
-    port: str = Argument(..., help=help_port),
-    password: str = Option("", help=help_password),
-):
+def terminal(port: PortStr, *, password: PasswordStr = ""):
     """Open up an interactive REPL.
 
     Press ctrl+] to exit.
diff --git a/belay/cli/update.py b/belay/cli/update.py
index 7411a32b..aa701070 100644
--- a/belay/cli/update.py
+++ b/belay/cli/update.py
@@ -1,14 +1,17 @@
-from typing import List
-
 from rich.console import Console
-from typer import Argument
 
 from belay.cli.clean import clean
 from belay.project import load_groups
 
 
-def update(packages: List[str] = Argument(None, help="Specific package(s) to update.")):
-    """Download new versions of dependencies."""
+def update(*packages: str):
+    """Download new versions of dependencies.
+
+    Parameters
+    ----------
+    *packages : str
+        Specific package(s) to update.
+    """
     console = Console()
     groups = load_groups()
     packages = packages if packages else None
diff --git a/belay/device.py b/belay/device.py
index 17bf5dd5..85cd7912 100644
--- a/belay/device.py
+++ b/belay/device.py
@@ -2,6 +2,7 @@
 import atexit
 import concurrent.futures
 import contextlib
+import importlib.resources as importlib_resources
 import linecache
 import re
 import shutil
@@ -11,7 +12,7 @@
 from tempfile import TemporaryDirectory
 from textwrap import dedent
 from types import ModuleType
-from typing import Any, Callable, Optional, TextIO, Tuple, TypeVar, Union, overload
+from typing import Any, Callable, Optional, TextIO, TypeVar, Union, overload
 
 from serial import SerialException
 from serial.tools.miniterm import Miniterm
@@ -48,11 +49,6 @@
 from .utils import Sentinel
 from .webrepl import WebreplToSerial
 
-if sys.version_info < (3, 9, 0):
-    import importlib_resources
-else:
-    import importlib.resources as importlib_resources
-
 P = ParamSpec("P")
 R = TypeVar("R")
 
@@ -510,7 +506,7 @@ def data_consumer(data):
 
         return result
 
-    def proxy(self, cmd: str, delete: Optional[bool] = None) -> Union[ProxyObject, Tuple[ProxyObject, ...]]:
+    def proxy(self, cmd: str, delete: Optional[bool] = None) -> Union[ProxyObject, tuple[ProxyObject, ...]]:
         """Create a :class:`.ProxyObject` for interacting with remote objects.
 
         This is a convenience method that combines object creation and proxy wrapping.
diff --git a/belay/device_support.py b/belay/device_support.py
index c236c992..7582b714 100644
--- a/belay/device_support.py
+++ b/belay/device_support.py
@@ -1,7 +1,7 @@
 import math
 from dataclasses import dataclass
 from threading import Lock
-from typing import Callable, Literal, Optional, Tuple, get_args
+from typing import Callable, Literal, Optional, get_args
 
 from attrs import define, field
 
@@ -47,10 +47,10 @@ class Implementation:
     """
 
     name: str
-    version: Tuple[int, int, int] = (0, 0, 0)
+    version: tuple[int, int, int] = (0, 0, 0)
     platform: str = ""
     arch: Optional[str] = field(default=None, converter=_arch_converter)
-    emitters: Tuple[str, ...] = ()
+    emitters: tuple[str, ...] = ()
 
 
 _method_metadata_counter_lock = Lock()
diff --git a/belay/helpers.py b/belay/helpers.py
index 997cc5ee..d522118f 100644
--- a/belay/helpers.py
+++ b/belay/helpers.py
@@ -1,3 +1,4 @@
+import importlib.resources as importlib_resources
 import secrets
 import string
 import sys
@@ -7,11 +8,6 @@
 
 from . import nativemodule_fnv1a32, snippets
 
-if sys.version_info < (3, 9, 0):
-    import importlib_resources
-else:
-    import importlib.resources as importlib_resources
-
 _python_identifier_chars = string.ascii_uppercase + string.ascii_lowercase + string.digits
 
 
diff --git a/belay/inspect.py b/belay/inspect.py
index 10bb8f55..e183d16b 100644
--- a/belay/inspect.py
+++ b/belay/inspect.py
@@ -1,6 +1,7 @@
 import ast
 import inspect
 import re
+from collections.abc import Sequence
 from io import StringIO
 from tokenize import (
     COMMENT,
@@ -12,7 +13,6 @@
     generate_tokens,
     untokenize,
 )
-from typing import Sequence, Tuple
 
 _pat_no_decorators = re.compile(r"^(\s*def\s)|(\s*async\s+def\s)|(.*(?<!\w)lambda(:|\s))")
 
@@ -60,7 +60,7 @@ def _remove_signature(code):
     return "\n".join(lines), lines_removed
 
 
-def getsource(f, *, strip_signature=False) -> Tuple[str, int, str]:
+def getsource(f, *, strip_signature=False) -> tuple[str, int, str]:
     """Get source code with mild post processing.
 
     * strips leading decorators.
diff --git a/belay/packagemanager/group.py b/belay/packagemanager/group.py
index 873025df..739315b0 100644
--- a/belay/packagemanager/group.py
+++ b/belay/packagemanager/group.py
@@ -3,7 +3,7 @@
 import tempfile
 from contextlib import nullcontext
 from pathlib import Path
-from typing import List, Optional
+from typing import Optional
 
 from rich.console import Console
 
@@ -100,7 +100,7 @@ def _download_package(self, package_name) -> bool:
 
     def download(
         self,
-        packages: Optional[List[str]] = None,
+        packages: Optional[list[str]] = None,
         console: Optional[Console] = None,
     ) -> None:
         """Download dependencies.
diff --git a/belay/packagemanager/models.py b/belay/packagemanager/models.py
index ce142e48..5d83148a 100644
--- a/belay/packagemanager/models.py
+++ b/belay/packagemanager/models.py
@@ -2,7 +2,7 @@
 """
 
 from pathlib import Path
-from typing import Dict, List, Optional
+from typing import Optional
 
 from pydantic import BaseModel as PydanticBaseModel
 from pydantic import ConfigDict, field_validator
@@ -19,7 +19,7 @@ class DependencySourceConfig(BaseModel):
     rename_to_init: bool = False
 
 
-DependencyList = List[DependencySourceConfig]
+DependencyList = list[DependencySourceConfig]
 
 
 def _dependencies_name_validator(dependencies) -> dict:
@@ -29,7 +29,7 @@ def _dependencies_name_validator(dependencies) -> dict:
     return dependencies
 
 
-def _dependencies_preprocessor(dependencies) -> Dict[str, List[dict]]:
+def _dependencies_preprocessor(dependencies) -> dict[str, list[dict]]:
     """Preprocess various dependencies based on dtype.
 
     * ``str`` -> single dependency that may get renamed to __init__.py, if appropriate.
@@ -92,7 +92,7 @@ def walk_dependencies(packages: dict):
 
 class GroupConfig(BaseModel):
     optional: bool = False
-    dependencies: Dict[str, DependencyList] = {}
+    dependencies: dict[str, DependencyList] = {}
 
     ##############
     # VALIDATORS #
@@ -129,13 +129,13 @@ class BelayConfig(BaseModel):
     ignore: Optional[list] = []
 
     # "main" dependencies
-    dependencies: Dict[str, DependencyList] = {}
+    dependencies: dict[str, DependencyList] = {}
 
     # Path to where dependency groups should be stored relative to project's root.
     dependencies_path: Path = Path(".belay/dependencies")
 
     # Other dependencies
-    group: Dict[str, GroupConfig] = {}
+    group: dict[str, GroupConfig] = {}
 
     ##############
     # VALIDATORS #
diff --git a/belay/project.py b/belay/project.py
index d2900dbf..5a972e60 100644
--- a/belay/project.py
+++ b/belay/project.py
@@ -1,7 +1,7 @@
 import platform
 from functools import lru_cache
 from pathlib import Path
-from typing import List, Union
+from typing import Union
 
 import tomli
 
@@ -80,7 +80,7 @@ def load_pyproject() -> BelayConfig:
 
 
 @lru_cache
-def load_groups() -> List[Group]:
+def load_groups() -> list[Group]:
     config = load_pyproject()
     groups = [Group("main", dependencies=config.dependencies)]
     groups.extend(Group(name, **definition.model_dump()) for name, definition in config.group.items())
diff --git a/belay/telnetlib.py b/belay/telnetlib.py
index 9654c793..81baa812 100644
--- a/belay/telnetlib.py
+++ b/belay/telnetlib.py
@@ -246,7 +246,7 @@ def msg(self, msg, *args):
 
         """
         if self.debuglevel > 0:
-            print("Telnet(%s,%s):" % (self.host, self.port), end=" ")
+            print("Telnet({},{}):".format(self.host, self.port), end=" ")
             if args:
                 print(msg % args)
             else:
diff --git a/belay/typing.py b/belay/typing.py
index 136bfd9a..22a27c06 100644
--- a/belay/typing.py
+++ b/belay/typing.py
@@ -1,7 +1,8 @@
+from collections.abc import Generator
 from pathlib import Path
-from typing import Callable, Dict, Generator, List, Set, Union
+from typing import Callable, Union
 
-PythonLiteral = Union[None, bool, bytes, int, float, str, List, Dict, Set]
+PythonLiteral = Union[None, bool, bytes, int, float, str, list, dict, set]
 BelayGenerator = Generator[PythonLiteral, None, None]
 BelayReturn = Union[BelayGenerator, PythonLiteral]
 BelayCallable = Callable[..., BelayReturn]
diff --git a/belay/usb_specifier.py b/belay/usb_specifier.py
index a1e36464..6216225d 100644
--- a/belay/usb_specifier.py
+++ b/belay/usb_specifier.py
@@ -1,4 +1,4 @@
-from typing import Dict, List, Optional
+from typing import Optional
 
 from pydantic import BaseModel, Field
 from serial.tools.list_ports import comports
@@ -13,7 +13,7 @@ def _normalize(val):
     return val
 
 
-def _dict_is_subset(subset: Dict, superset: Dict) -> bool:
+def _dict_is_subset(subset: dict, superset: dict) -> bool:
     """Tests if ``subset`` dictionary is a subset of ``superset`` dictionary."""
     for subset_key, subset_value in subset.items():
         try:
@@ -65,7 +65,7 @@ def populated(self):
         return bool(self.model_dump(exclude_none=True))
 
 
-def list_devices() -> List[UsbSpecifier]:
+def list_devices() -> list[UsbSpecifier]:
     """Lists available device ports.
 
     Returns
diff --git a/examples/06_external_modules_and_file_sync/circuitpython.py b/examples/06_external_modules_and_file_sync/circuitpython.py
index 419ac4ac..08e0c1d9 100644
--- a/examples/06_external_modules_and_file_sync/circuitpython.py
+++ b/examples/06_external_modules_and_file_sync/circuitpython.py
@@ -42,7 +42,7 @@ def set_led(value):
 
 @device.task
 def read_file(fn):
-    with open(fn, "r") as f:
+    with open(fn) as f:
         return f.read()
 
 
diff --git a/examples/06_external_modules_and_file_sync/main.py b/examples/06_external_modules_and_file_sync/main.py
index a6385321..4c9e1ef9 100644
--- a/examples/06_external_modules_and_file_sync/main.py
+++ b/examples/06_external_modules_and_file_sync/main.py
@@ -59,7 +59,7 @@ def set_somemodule_led(pin, value):
 
 @device.task
 def read_file(fn):
-    with open(fn, "r") as f:
+    with open(fn) as f:
         return f.read()
 
 
diff --git a/poetry.lock b/poetry.lock
index e572f2cc..2d3e7bc3 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -164,9 +164,6 @@ files = [
     {file = "annotated_types-0.7.0.tar.gz", hash = "sha256:aff07c09a53a08bc8cfccb9c85b05f1aa9a2a6f23728d790723543408344ce89"},
 ]
 
-[package.dependencies]
-typing-extensions = {version = ">=4.0.0", markers = "python_version < \"3.9\""}
-
 [[package]]
 name = "appnope"
 version = "0.1.4"
@@ -253,9 +250,6 @@ files = [
     {file = "babel-2.17.0.tar.gz", hash = "sha256:0c54cffb19f690cdcc52a3b50bcbf71e07a808d1c80d549f2459b9d2cf0afb9d"},
 ]
 
-[package.dependencies]
-pytz = {version = ">=2015.7", markers = "python_version < \"3.9\""}
-
 [package.extras]
 dev = ["backports.zoneinfo ; python_version < \"3.9\"", "freezegun (>=1.0,<2.0)", "jinja2 (>=3.0)", "pytest (>=6.0)", "pytest-cov", "pytz", "setuptools", "tzdata ; sys_platform == \"win32\""]
 
@@ -450,7 +444,7 @@ version = "8.1.8"
 description = "Composable command line interface toolkit"
 optional = false
 python-versions = ">=3.7"
-groups = ["main", "dev"]
+groups = ["dev"]
 files = [
     {file = "click-8.1.8-py3-none-any.whl", hash = "sha256:63c132bbbed01578a06712a2d1f497bb62d9c1c0d329b7903a866228027263b2"},
     {file = "click-8.1.8.tar.gz", hash = "sha256:ed53c9d8990d83c2a27deae68e4ee337473f6330c040a31d4225c9574d16096a"},
@@ -465,12 +459,12 @@ version = "0.4.6"
 description = "Cross-platform colored terminal text."
 optional = false
 python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,!=3.6.*,>=2.7"
-groups = ["main", "debug", "dev", "docs"]
+groups = ["debug", "dev", "docs"]
 files = [
     {file = "colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6"},
     {file = "colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44"},
 ]
-markers = {main = "platform_system == \"Windows\"", debug = "sys_platform == \"win32\"", dev = "platform_system == \"Windows\" or sys_platform == \"win32\"", docs = "sys_platform == \"win32\""}
+markers = {debug = "sys_platform == \"win32\"", dev = "platform_system == \"Windows\" or sys_platform == \"win32\"", docs = "sys_platform == \"win32\""}
 
 [[package]]
 name = "coverage"
@@ -560,6 +554,30 @@ tomli = {version = "*", optional = true, markers = "python_full_version <= \"3.1
 [package.extras]
 toml = ["tomli ; python_full_version <= \"3.11.0a6\""]
 
+[[package]]
+name = "cyclopts"
+version = "3.24.0"
+description = "Intuitive, easy CLIs based on type hints."
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "cyclopts-3.24.0-py3-none-any.whl", hash = "sha256:809d04cde9108617106091140c3964ee6fceb33cecdd537f7ffa360bde13ed71"},
+    {file = "cyclopts-3.24.0.tar.gz", hash = "sha256:de6964a041dfb3c57bf043b41e68c43548227a17de1bad246e3a0bfc5c4b7417"},
+]
+
+[package.dependencies]
+attrs = ">=23.1.0"
+docstring-parser = {version = ">=0.15", markers = "python_version < \"4.0\""}
+rich = ">=13.6.0"
+rich-rst = ">=1.3.1,<2.0.0"
+typing-extensions = {version = ">=4.8.0", markers = "python_version < \"3.11\""}
+
+[package.extras]
+toml = ["tomli (>=2.0.0) ; python_version < \"3.11\""]
+trio = ["trio (>=0.10.0)"]
+yaml = ["pyyaml (>=6.0.1)"]
+
 [[package]]
 name = "decorator"
 version = "5.2.1"
@@ -584,13 +602,31 @@ files = [
     {file = "distlib-0.3.9.tar.gz", hash = "sha256:a60f20dea646b8a33f3e7772f74dc0b2d0772d2837ee1342a00645c81edf9403"},
 ]
 
+[[package]]
+name = "docstring-parser"
+version = "0.17.0"
+description = "Parse Python docstrings in reST, Google and Numpydoc format"
+optional = false
+python-versions = ">=3.8"
+groups = ["main"]
+markers = "python_version < \"4.0\""
+files = [
+    {file = "docstring_parser-0.17.0-py3-none-any.whl", hash = "sha256:cf2569abd23dce8099b300f9b4fa8191e9582dda731fd533daf54c4551658708"},
+    {file = "docstring_parser-0.17.0.tar.gz", hash = "sha256:583de4a309722b3315439bb31d64ba3eebada841f2e2cee23b99df001434c912"},
+]
+
+[package.extras]
+dev = ["pre-commit (>=2.16.0) ; python_version >= \"3.9\"", "pydoctor (>=25.4.0)", "pytest"]
+docs = ["pydoctor (>=25.4.0)"]
+test = ["pytest"]
+
 [[package]]
 name = "docutils"
 version = "0.18.1"
 description = "Docutils -- Python Documentation Utilities"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
-groups = ["docs"]
+groups = ["main", "docs"]
 files = [
     {file = "docutils-0.18.1-py2.py3-none-any.whl", hash = "sha256:23010f129180089fbcd3bc08cfefccb3b890b0050e1ca00c867036e9d161b98c"},
     {file = "docutils-0.18.1.tar.gz", hash = "sha256:679987caf361a7539d76e584cbeddc311e3aee937877c87346f31debc63e9d06"},
@@ -887,7 +923,7 @@ description = "Read metadata from Python packages"
 optional = false
 python-versions = ">=3.8"
 groups = ["docs"]
-markers = "python_version < \"3.10\""
+markers = "python_version == \"3.9\""
 files = [
     {file = "importlib_metadata-8.5.0-py3-none-any.whl", hash = "sha256:45e54197d28b7a7f1559e60b95e7c567032b602131fbd588f1497f47880aa68b"},
     {file = "importlib_metadata-8.5.0.tar.gz", hash = "sha256:71522656f0abace1d072b9e5481a48f07c138e00f079c38c8f883823f9c26bd7"},
@@ -905,30 +941,6 @@ perf = ["ipython"]
 test = ["flufl.flake8", "importlib-resources (>=1.3) ; python_version < \"3.9\"", "jaraco.test (>=5.4)", "packaging", "pyfakefs", "pytest (>=6,!=8.1.*)", "pytest-perf (>=0.9.2)"]
 type = ["pytest-mypy"]
 
-[[package]]
-name = "importlib-resources"
-version = "6.4.5"
-description = "Read resources from Python packages"
-optional = false
-python-versions = ">=3.8"
-groups = ["main"]
-markers = "python_version == \"3.8\""
-files = [
-    {file = "importlib_resources-6.4.5-py3-none-any.whl", hash = "sha256:ac29d5f956f01d5e4bb63102a5a19957f1b9175e45649977264a1416783bb717"},
-    {file = "importlib_resources-6.4.5.tar.gz", hash = "sha256:980862a1d16c9e147a59603677fa2aa5fd82b87f223b6cb870695bcfce830065"},
-]
-
-[package.dependencies]
-zipp = {version = ">=3.1.0", markers = "python_version < \"3.10\""}
-
-[package.extras]
-check = ["pytest-checkdocs (>=2.4)", "pytest-ruff (>=0.2.1) ; sys_platform != \"cygwin\""]
-cover = ["pytest-cov"]
-doc = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (>=3.5)", "sphinx-lint"]
-enabler = ["pytest-enabler (>=2.2)"]
-test = ["jaraco.test (>=5.4)", "pytest (>=6,!=8.1.*)", "zipp (>=3.17)"]
-type = ["pytest-mypy"]
-
 [[package]]
 name = "iniconfig"
 version = "2.1.0"
@@ -1859,19 +1871,6 @@ files = [
 [package.dependencies]
 pytest = ">=7.0.0"
 
-[[package]]
-name = "pytz"
-version = "2025.2"
-description = "World timezone definitions, modern and historical"
-optional = false
-python-versions = "*"
-groups = ["docs"]
-markers = "python_version == \"3.8\""
-files = [
-    {file = "pytz-2025.2-py2.py3-none-any.whl", hash = "sha256:5ddf76296dd8c44c26eb8f4b6f35488f3ccbf6fbbd7adee0b7262d43f0ec2f00"},
-    {file = "pytz-2025.2.tar.gz", hash = "sha256:360b9e3dbb49a209c21ad61809c7fb453643e048b38924c765813546746e81c3"},
-]
-
 [[package]]
 name = "pyyaml"
 version = "6.0.2"
@@ -1993,17 +1992,24 @@ typing-extensions = {version = ">=4.0.0,<5.0", markers = "python_version < \"3.1
 jupyter = ["ipywidgets (>=7.5.1,<9)"]
 
 [[package]]
-name = "shellingham"
-version = "1.5.4"
-description = "Tool to Detect Surrounding Shell"
+name = "rich-rst"
+version = "1.3.2"
+description = "A beautiful reStructuredText renderer for rich"
 optional = false
-python-versions = ">=3.7"
+python-versions = "*"
 groups = ["main"]
 files = [
-    {file = "shellingham-1.5.4-py2.py3-none-any.whl", hash = "sha256:7ecfff8f2fd72616f7481040475a65b2bf8af90a56c89140852d1120324e8686"},
-    {file = "shellingham-1.5.4.tar.gz", hash = "sha256:8dbca0739d487e5bd35ab3ca4b36e11c4078f3a234bfce294b0a0291363404de"},
+    {file = "rich_rst-1.3.2-py3-none-any.whl", hash = "sha256:a99b4907cbe118cf9d18b0b44de272efa61f15117c61e39ebdc431baf5df722a"},
+    {file = "rich_rst-1.3.2.tar.gz", hash = "sha256:a1196fdddf1e364b02ec68a05e8ff8f6914fee10fbca2e6b6735f166bb0da8d4"},
 ]
 
+[package.dependencies]
+docutils = "*"
+rich = ">=12.0.0"
+
+[package.extras]
+docs = ["sphinx"]
+
 [[package]]
 name = "smmap"
 version = "5.0.2"
@@ -2272,24 +2278,6 @@ files = [
 docs = ["myst-parser", "pydata-sphinx-theme", "sphinx"]
 test = ["argcomplete (>=3.0.3)", "mypy (>=1.7.0)", "pre-commit", "pytest (>=7.0,<8.2)", "pytest-mock", "pytest-mypy-testing"]
 
-[[package]]
-name = "typer"
-version = "0.16.0"
-description = "Typer, build great CLIs. Easy to code. Based on Python type hints."
-optional = false
-python-versions = ">=3.7"
-groups = ["main"]
-files = [
-    {file = "typer-0.16.0-py3-none-any.whl", hash = "sha256:1f79bed11d4d02d4310e3c1b7ba594183bcedb0ac73b27a9e5f28f6fb5b98855"},
-    {file = "typer-0.16.0.tar.gz", hash = "sha256:af377ffaee1dbe37ae9440cb4e8f11686ea5ce4e9bae01b84ae7c63b87f1dd3b"},
-]
-
-[package.dependencies]
-click = ">=8.0.0"
-rich = ">=10.11.0"
-shellingham = ">=1.3.0"
-typing-extensions = ">=3.7.4.3"
-
 [[package]]
 name = "typing-extensions"
 version = "4.13.2"
@@ -2472,12 +2460,12 @@ version = "3.20.2"
 description = "Backport of pathlib-compatible object wrapper for zip files"
 optional = false
 python-versions = ">=3.8"
-groups = ["main", "docs"]
+groups = ["docs"]
+markers = "python_version == \"3.9\""
 files = [
     {file = "zipp-3.20.2-py3-none-any.whl", hash = "sha256:a817ac80d6cf4b23bf7f2828b7cabf326f15a001bea8b1f9b49631780ba28350"},
     {file = "zipp-3.20.2.tar.gz", hash = "sha256:bc9eb26f4506fda01b81bcde0ca78103b6e62f991b381fec825435c836edbc29"},
 ]
-markers = {main = "python_version == \"3.8\"", docs = "python_version < \"3.10\""}
 
 [package.extras]
 check = ["pytest-checkdocs (>=2.4)", "pytest-ruff (>=0.2.1) ; sys_platform != \"cygwin\""]
@@ -2489,5 +2477,5 @@ type = ["pytest-mypy"]
 
 [metadata]
 lock-version = "2.1"
-python-versions = ">=3.8"
-content-hash = "2811eed33a649b86c63ef4b225613fcb07c4cacad85ee6f4e8cdd7945d3d5c84"
+python-versions = ">=3.9"
+content-hash = "3212853bd0708a306dbe68111aefe597bd041c150322c53ad65d55932ea3042f"
diff --git a/pyproject.toml b/pyproject.toml
index 3249c6c8..1424368e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,9 +23,9 @@ belay = "belay.cli.main:run_app"
 
 [tool.poetry.dependencies]
 # Be as loose as possible if writing a library.
-python = ">=3.8"
+python = ">=3.9"
 pyserial = ">=3.1"
-typer = {extras = ["all"], version = ">=0.6.0"}
+cyclopts = ">=3.22.0"
 pathspec = ">=0.10.3"
 tomli = ">=2.0.1"
 autoregistry = ">=0.10.1"
@@ -36,7 +36,6 @@ pydantic = ">=2.0.0"
 typing-extensions = ">=4.5.0"
 questionary = ">=2.0.0"
 packaging = ">=20.4"
-importlib_resources = {version = ">=3.0.0", python = "<3.9"}
 attrs = ">=21.0.0"
 
 [tool.poetry.group.docs.dependencies]
@@ -105,7 +104,7 @@ markers = [
 ]
 
 [tool.ruff]
-target-version = 'py38'
+target-version = 'py39'
 line-length = 120  # Must agree with Black
 exclude = [
     "migrations",
@@ -164,8 +163,6 @@ select = [
 [tool.ruff.lint.flake8-bugbear]
 extend-immutable-calls = [
     "chr",
-    "typer.Argument",
-    "typer.Option",
 ]
 
 [tool.ruff.lint.pydocstyle]
@@ -204,6 +201,5 @@ paths=["belay"]
 deps-file="pyproject.toml"
 sections=["tool.poetry.dependencies"]
 exclude-deps =[
-  "importlib_resources",
   "pydantic",
 ]
diff --git a/tests/cli/test_exec.py b/tests/cli/test_exec.py
index 0d90b7d6..56b23133 100644
--- a/tests/cli/test_exec.py
+++ b/tests/cli/test_exec.py
@@ -1,5 +1,10 @@
-def test_exec_basic(mocker, mock_device, cli_runner):
+from belay.cli.main import app
+from tests.conftest import run_cli
+
+
+def test_exec_basic(mocker, mock_device):
     mock_device.patch("belay.cli.exec.Device")
-    result = cli_runner("exec", "print('hello world')")
-    assert result.exit_code == 0
+    exit_code = run_cli(app, ["exec", "/dev/ttyUSB0", "print('hello world')", "--password", "password"])
+    assert exit_code == 0
+    mock_device.cls_assert_common()
     mock_device.inst.assert_called_once_with("print('hello world')")
diff --git a/tests/cli/test_info.py b/tests/cli/test_info.py
index d65dd0da..c79f64cb 100644
--- a/tests/cli/test_info.py
+++ b/tests/cli/test_info.py
@@ -1,8 +1,14 @@
-def test_info_basic(mocker, mock_device, cli_runner, tmp_path):
+from belay.cli.main import app
+from tests.conftest import run_cli
+
+
+def test_info_basic(mocker, mock_device, capsys):
     mock_device.patch("belay.cli.info.Device")
     mock_device.inst.implementation.name = "testingpython"
     mock_device.inst.implementation.version = (4, 7, 9)
     mock_device.inst.implementation.platform = "pytest"
-    result = cli_runner("info")
-    assert result.exit_code == 0
-    assert result.output == "testingpython v4.7.9 - pytest\n"
+    exit_code = run_cli(app, ["info", "/dev/ttyUSB0", "--password", "password"])
+    assert exit_code == 0
+    mock_device.cls_assert_common()
+    captured = capsys.readouterr()
+    assert captured.out == "testingpython v4.7.9 - pytest\n"
diff --git a/tests/cli/test_install.py b/tests/cli/test_install.py
index 5478a51c..5cf90122 100644
--- a/tests/cli/test_install.py
+++ b/tests/cli/test_install.py
@@ -1,10 +1,7 @@
 from pathlib import Path
 
-from typer.testing import CliRunner
-
-from belay.cli import app
-
-cli_runner = CliRunner()
+from belay.cli.main import app
+from tests.conftest import run_cli
 
 
 def test_install_no_pkg(tmp_path, mocker, mock_device):
@@ -15,23 +12,11 @@ def test_install_no_pkg(tmp_path, mocker, mock_device):
     mock_load_toml = mocker.patch("belay.project.load_toml", return_value=toml)
     mock_device.patch("belay.cli.install.Device")
 
-    result = cli_runner.invoke(
-        app,
-        [
-            "install",
-            "/dev/ttyUSB0",
-            "--password",
-            "password",
-            "--run",
-            str(main_py),
-        ],
-        catch_exceptions=False,
-    )
-
-    assert result.exit_code == 0
+    exit_code = run_cli(app, ["install", "/dev/ttyUSB0", "--run", str(main_py), "--password", "password"])
+    assert exit_code == 0
 
     mock_load_toml.assert_called_once()
-    mock_device.cls.assert_called_once_with("/dev/ttyUSB0", password="password")
+    mock_device.cls_assert_common()
     mock_device.inst.sync.assert_called_once_with(  # Dependencies sync
         mocker.ANY,
         progress_update=mocker.ANY,
@@ -52,15 +37,11 @@ def test_install_basic(tmp_path, mocker, mock_device):
     mocker.patch("belay.cli.install.find_project_folder", return_value=Path())
     mock_device.patch("belay.cli.install.Device")
 
-    result = cli_runner.invoke(
-        app,
-        ["install", "/dev/ttyUSB0", "--password", "password"],
-        catch_exceptions=False,
-    )
-    assert result.exit_code == 0
+    exit_code = run_cli(app, ["install", "/dev/ttyUSB0", "--password", "password"])
+    assert exit_code == 0
 
     mock_load_toml.assert_called_once()
-    mock_device.cls.assert_called_once_with("/dev/ttyUSB0", password="password")
+    mock_device.cls_assert_common()
     mock_device.inst.sync.assert_has_calls(
         [
             mocker.call(
diff --git a/tests/cli/test_run.py b/tests/cli/test_run.py
index 465cc495..ca9270ee 100644
--- a/tests/cli/test_run.py
+++ b/tests/cli/test_run.py
@@ -1,7 +1,12 @@
-def test_run_basic(mocker, mock_device, cli_runner, tmp_path):
+from belay.cli.main import app
+from tests.conftest import run_cli
+
+
+def test_run_basic(mocker, mock_device, tmp_path):
     mock_device.patch("belay.cli.run.Device")
     py_file = tmp_path / "foo.py"
     py_file.write_text("print('hello')\nprint('world')")
-    result = cli_runner("run", str(py_file))
-    assert result.exit_code == 0
+    exit_code = run_cli(app, ["run", "/dev/ttyUSB0", str(py_file), "--password", "password"])
+    assert exit_code == 0
+    mock_device.cls_assert_common()
     mock_device.inst.assert_called_once_with("print('hello')\nprint('world')")
diff --git a/tests/cli/test_sync.py b/tests/cli/test_sync.py
index 495b7a64..7f13b6c9 100644
--- a/tests/cli/test_sync.py
+++ b/tests/cli/test_sync.py
@@ -1,10 +1,14 @@
 from pathlib import Path
 
+from belay.cli.main import app
+from tests.conftest import run_cli
 
-def test_sync_basic(mocker, mock_device, cli_runner):
+
+def test_sync_basic(mocker, mock_device):
     mock_device.patch("belay.cli.sync.Device")
-    result = cli_runner("sync", "foo")
-    assert result.exit_code == 0
+    exit_code = run_cli(app, ["sync", "/dev/ttyUSB0", "foo", "--password", "password"])
+    assert exit_code == 0
+    mock_device.cls_assert_common()
     mock_device.inst.sync.assert_called_once_with(
         Path("foo"),
         dst="/",
diff --git a/tests/cli/test_update.py b/tests/cli/test_update.py
index c9a0a48e..25c2b3d7 100644
--- a/tests/cli/test_update.py
+++ b/tests/cli/test_update.py
@@ -1,11 +1,8 @@
 import os
 
-from typer.testing import CliRunner
-
-from belay.cli import app
+from belay.cli.main import app
 from belay.packagemanager import Group
-
-cli_runner = CliRunner()
+from tests.conftest import run_cli
 
 
 def test_update(mocker, tmp_path):
@@ -17,8 +14,10 @@ def test_update(mocker, tmp_path):
     groups = [Group("name", dependencies={"foo": "foo.py"})]
     mock_download = mocker.patch.object(groups[0], "download")
     mock_load_groups = mocker.patch("belay.cli.update.load_groups", return_value=groups)
-    res = cli_runner.invoke(app, ["update"])
-    assert res.exit_code == 0
+
+    exit_code = run_cli(app, ["update"])
+    assert exit_code == 0
+
     mock_load_groups.assert_called_once_with()
     mock_download.assert_called_once_with(
         packages=None,
@@ -35,8 +34,10 @@ def test_update_specific_packages(mocker, tmp_path):
     groups = [Group("name", dependencies={"foo": "foo.py", "bar": "bar.py", "baz": "baz.py"})]
     mock_download = mocker.patch.object(groups[0], "download")
     mock_load_groups = mocker.patch("belay.cli.update.load_groups", return_value=groups)
-    res = cli_runner.invoke(app, ["update", "bar", "baz"])
-    assert res.exit_code == 0
+
+    exit_code = run_cli(app, ["update", "bar", "baz"])
+    assert exit_code == 0
+
     mock_load_groups.assert_called_once_with()
     mock_download.assert_called_once_with(
         packages=["bar", "baz"],
diff --git a/tests/conftest.py b/tests/conftest.py
index 7c1c14b2..a3539f5f 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -5,15 +5,40 @@
 from pathlib import Path
 
 import pytest
-from typer.testing import CliRunner
 
 import belay
 import belay.cli.common
 import belay.project
-from belay.cli import app
 from belay.utils import env_parse_bool
 
 
+def run_cli(app, args):
+    """Run a CLI app with support for both Cyclopts v3 and v4.
+
+    Cyclopts v3 returns None on success.
+    Cyclopts v4 raises SystemExit with code 0 on success.
+
+    Parameters
+    ----------
+    app : callable
+        The CLI app to run.
+    args : list
+        Command line arguments.
+
+    Returns
+    -------
+    int
+        Exit code (0 for success).
+    """
+    try:
+        result = app(args)
+        # v3 behavior: returns None or int
+        return result if isinstance(result, int) else 0
+    except SystemExit as e:
+        # v4 behavior: raises SystemExit
+        return e.code if e.code is not None else 0
+
+
 class MockDevice:
     def __init__(self, mocker):
         self.mocker = mocker
@@ -53,18 +78,6 @@ def mock_device(mocker):
     return MockDevice(mocker)
 
 
-@pytest.fixture
-def cli_runner(mock_device):
-    cli_runner = CliRunner()
-
-    def run(cmd, *args):
-        result = cli_runner.invoke(app, [cmd, "/dev/ttyUSB0", *args, "--password", "password"])
-        mock_device.cls_assert_common()
-        return result
-
-    return run
-
-
 @pytest.fixture(
     params=(
         [
diff --git a/tools/update-fnv1a32.py b/tools/update-fnv1a32.py
index 6ac57a21..b5c0b756 100644
--- a/tools/update-fnv1a32.py
+++ b/tools/update-fnv1a32.py
@@ -9,11 +9,10 @@
 import shutil
 import tempfile
 from pathlib import Path
-from typing import Dict, List
 from urllib.request import urlopen, urlretrieve
 
 
-def get_release_assets(version: str) -> List[Dict]:
+def get_release_assets(version: str) -> list[dict]:
     """Get release assets from GitHub API."""
     if not version.startswith("v"):
         version = f"v{version}"
@@ -31,7 +30,7 @@ def get_release_assets(version: str) -> List[Dict]:
         return []
 
 
-def download_and_extract_mpy_files(assets: List[Dict], temp_dir: Path) -> List[Path]:
+def download_and_extract_mpy_files(assets: list[dict], temp_dir: Path) -> list[Path]:
     """Download and extract .mpy files from release assets."""
     mpy_files = []
 
@@ -64,7 +63,7 @@ def convert_filename(original_name: str) -> str:
     return original_name
 
 
-def copy_files_to_destination(mpy_files: List[Path], dest_dir: Path):
+def copy_files_to_destination(mpy_files: list[Path], dest_dir: Path):
     """Copy .mpy files to the destination directory with proper naming."""
     dest_dir.mkdir(parents=True, exist_ok=True)