diff --git a/examples/demo.py b/examples/demo.py
index a0c95c9..3367dd7 100644
--- a/examples/demo.py
+++ b/examples/demo.py
@@ -4,8 +4,6 @@
 it doubles as a smoke check that ``apply_action`` still behaves as intended.
 """
 
-from __future__ import annotations
-
 from functools import reduce
 
 from mundane.engine.actions import Action, CastInstant, IllegalAction, PassPriority, PlayCard
diff --git a/src/mundane/api/app.py b/src/mundane/api/app.py
index 39d285c..391a972 100644
--- a/src/mundane/api/app.py
+++ b/src/mundane/api/app.py
@@ -9,8 +9,6 @@
 (create / get / save) makes swapping it for Redis or SQLite a localised change.
 """
 
-from __future__ import annotations
-
 from typing import Any
 from uuid import uuid4
 
diff --git a/src/mundane/api/schemas.py b/src/mundane/api/schemas.py
index 6accbbc..d5806e5 100644
--- a/src/mundane/api/schemas.py
+++ b/src/mundane/api/schemas.py
@@ -10,8 +10,6 @@
 is pure translation.
 """
 
-from __future__ import annotations
-
 from typing import TYPE_CHECKING
 
 from mundane.engine.actions import CastInstant, IllegalAction, PassPriority, PlayCard
diff --git a/src/mundane/engine/actions.py b/src/mundane/engine/actions.py
index 2c28a19..45bfd1b 100644
--- a/src/mundane/engine/actions.py
+++ b/src/mundane/engine/actions.py
@@ -6,8 +6,6 @@
 from it so the wire format can never drift from the engine.
 """
 
-from __future__ import annotations
-
 from dataclasses import dataclass
 
 
@@ -39,7 +37,7 @@ class PassPriority:
 """The closed set of moves a player may submit."""
 
 
-ACTION_TYPES: dict[str, type[PlayCard | CastInstant | PassPriority]] = {
+ACTION_TYPES: dict[str, type[Action]] = {
     "play_card": PlayCard,
     "cast_instant": CastInstant,
     "pass_priority": PassPriority,
diff --git a/src/mundane/engine/cards.py b/src/mundane/engine/cards.py
index 33b4526..41510fa 100644
--- a/src/mundane/engine/cards.py
+++ b/src/mundane/engine/cards.py
@@ -4,8 +4,6 @@
 through :data:`CARD_LIBRARY` is how the engine recovers a card's type, cost, and effect.
 """
 
-from __future__ import annotations
-
 from .state import Card, CardType, GameState, StackItem
 
 
diff --git a/src/mundane/engine/game.py b/src/mundane/engine/game.py
index 61e5d7b..f157ce7 100644
--- a/src/mundane/engine/game.py
+++ b/src/mundane/engine/game.py
@@ -6,8 +6,6 @@
 is never logged.
 """
 
-from __future__ import annotations
-
 from dataclasses import dataclass, field
 from typing import TYPE_CHECKING
 
diff --git a/src/mundane/engine/rules.py b/src/mundane/engine/rules.py
index 9f7a126..bf11f26 100644
--- a/src/mundane/engine/rules.py
+++ b/src/mundane/engine/rules.py
@@ -6,8 +6,6 @@
 ``final = reduce(apply_action, actions, initial)``.
 """
 
-from __future__ import annotations
-
 from .actions import Action, CastInstant, IllegalAction, PassPriority, PlayCard
 from .cards import CARD_LIBRARY
 from .state import PERMANENTS, PHASES, CardType, GameState, StackItem
diff --git a/src/mundane/engine/serialize.py b/src/mundane/engine/serialize.py
index 700d932..1f42563 100644
--- a/src/mundane/engine/serialize.py
+++ b/src/mundane/engine/serialize.py
@@ -6,8 +6,6 @@
 hand-written decoder.
 """
 
-from __future__ import annotations
-
 import dataclasses
 import json
 from enum import Enum
diff --git a/src/mundane/engine/state.py b/src/mundane/engine/state.py
index 29b65ae..f350f74 100644
--- a/src/mundane/engine/state.py
+++ b/src/mundane/engine/state.py
@@ -7,14 +7,12 @@
 :class:`GameState` round-trip through JSON.
 """
 
-from __future__ import annotations
-
 from collections.abc import Callable
 from dataclasses import dataclass, field
-from enum import Enum
+from enum import StrEnum
 
 
-class CardType(Enum):
+class CardType(StrEnum):
     """The five kinds of card. The first three are permanents (they stay on the board)."""
 
     PERSON = "person"  # creature-like; stays on the board once it resolves
diff --git a/tests/test_api.py b/tests/test_api.py
index dedb0a2..9bae231 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -1,7 +1,5 @@
 """API tests: drive the Litestar app over HTTP and confirm it is a thin shell over the engine."""
 
-from __future__ import annotations
-
 from typing import TYPE_CHECKING
 
 import pytest
diff --git a/tests/test_replay.py b/tests/test_replay.py
index 3e5b51d..9f4730f 100644
--- a/tests/test_replay.py
+++ b/tests/test_replay.py
@@ -1,7 +1,5 @@
 """Replay tests: a game's state is a pure fold of its action log (the event-sourcing property)."""
 
-from __future__ import annotations
-
 from functools import reduce
 
 import pytest
diff --git a/tests/test_rules.py b/tests/test_rules.py
index 6f46722..c07d229 100644
--- a/tests/test_rules.py
+++ b/tests/test_rules.py
@@ -1,7 +1,5 @@
 """Engine rules tests: the legality preconditions mirrored one-for-one, plus the countered party."""
 
-from __future__ import annotations
-
 import dataclasses
 import json
 from copy import deepcopy