diff --git a/itchcraft/api.py b/itchcraft/api.py
index 9363b4e..0e5a8c8 100644
--- a/itchcraft/api.py
+++ b/itchcraft/api.py
@@ -1,7 +1,6 @@
 """The primary module in itchcraft."""
 
 from contextlib import ExitStack
-from dataclasses import dataclass
 
 from . import devices, prefs
 from .errors import CliError
@@ -17,17 +16,6 @@
 logger = get_logger(__name__)
 
 
-@dataclass(frozen=True)
-class StartParams:
-    """Parameters for the `start` method or CLI subcommand."""
-
-    duration: CliEnum[Duration] = prefs.default(Duration)
-    generation: CliEnum[Generation] = prefs.default(Generation)
-    skin_sensitivity: CliEnum[SkinSensitivity] = prefs.default(
-        SkinSensitivity
-    )
-
-
 # pylint: disable=too-few-public-methods
 class Api:
     """Tech demo for interfacing with heat-based USB insect bite healers"""
@@ -35,7 +23,6 @@ class Api:
     # pylint: disable=no-self-use
     def start(
         self,
-        # Re-enumerating all the `StartParams` fields to make Fire happy
         duration: CliEnum[Duration] = prefs.default(Duration),
         generation: CliEnum[Generation] = prefs.default(Generation),
         skin_sensitivity: CliEnum[SkinSensitivity] = prefs.default(
diff --git a/tests/test_heat_it.py b/tests/test_heat_it.py
index 3afd3ea..394f474 100644
--- a/tests/test_heat_it.py
+++ b/tests/test_heat_it.py
@@ -5,19 +5,30 @@
     AbstractContextManager,
     nullcontext,
 )
-from dataclasses import asdict
-from typing import Optional, Union
+from typing import Optional, TypedDict, Union
 from unittest.mock import ANY
 
 import pytest
 import pytest_mock
 
 from itchcraft import Api, devices
-from itchcraft.api import StartParams
 from itchcraft.backend import BulkTransferDevice
 from itchcraft.device import Device
 from itchcraft.heat_it import HeatItDevice
-from itchcraft.prefs import Duration, Generation, SkinSensitivity
+from itchcraft.prefs import (
+    CliEnum,
+    Duration,
+    Generation,
+    SkinSensitivity,
+)
+
+
+class StartParams(TypedDict, total=False):
+    """Parameters for the `start` method in parameterized tests."""
+
+    duration: CliEnum[Duration]
+    generation: CliEnum[Generation]
+    skin_sensitivity: CliEnum[SkinSensitivity]
 
 
 @pytest.fixture(name='dummy_device')
@@ -99,7 +110,7 @@ def test_child_sensitive_short(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x00, 0x00, 0x08],
@@ -146,7 +157,7 @@ def test_child_sensitive_medium(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x00, 0x01, 0x09],
@@ -193,7 +204,7 @@ def test_child_sensitive_long(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x00, 0x02, 0x0A],
@@ -235,7 +246,7 @@ def test_adult_sensitive_short(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x02, 0x00, 0x0A],
@@ -275,7 +286,7 @@ def test_adult_sensitive_medium(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x02, 0x01, 0x0B],
@@ -315,7 +326,7 @@ def test_adult_sensitive_long(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x02, 0x02, 0x0C],
@@ -358,7 +369,7 @@ def test_child_regular_short(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x01, 0x00, 0x09],
@@ -399,7 +410,7 @@ def test_child_regular_medium(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x01, 0x01, 0x0A],
@@ -440,7 +451,7 @@ def test_child_regular_long(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x01, 0x02, 0x0B],
@@ -481,7 +492,7 @@ def test_adult_regular_short(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x03, 0x00, 0x0B],
@@ -517,7 +528,7 @@ def test_adult_regular_medium(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x03, 0x01, 0x0C],
@@ -553,7 +564,7 @@ def test_adult_regular_long(
     bulk_transfer: pytest_mock.MockType,
     preferences: StartParams,
 ) -> None:
-    Api().start(**asdict(preferences))
+    Api().start(**preferences)
     bulk_transfer.assert_called_with(
         ANY,
         [0xFF, 0x08, 0x03, 0x02, 0x0D],