Apply attack rules to chase guards

packages/domain/src/sagasmith_dnd/chase_engine.py

@@ -24,7 +24,7 @@
 )
 from sagasmith_dnd.conditions import apply_condition_change, condition_ids
 from sagasmith_dnd.editions import DEFAULT_CHARACTER_EDITION, normalize_dnd_edition
-from sagasmith_dnd.engine import roll, roll_d20
+from sagasmith_dnd.engine import resolve_attack, roll
 from sagasmith_dnd.rule_engine import ResolutionContext
 
 CHASE_BOUNDARY_IDS = (
@@ -421,24 +421,26 @@ def _guard_attack(
 ) -> tuple[dict[str, Any], dict[str, Any]]:
     if moved_ft < 20:
         return sheet, {"triggered": False, "reason": "moved less than 20 feet"}
-    attack = roll_d20(rng=rng)
-    attack_total = int(attack["natural"]) + 3
     derived_ac = actor_derived(actor).get("armor_class")
     ac = 10 if derived_ac is None else int(derived_ac)
-    hit = attack_total >= ac
+    attack = resolve_attack(armor_class=ac, attack_bonus=3, rng=rng)
     result: dict[str, Any] = {
         "triggered": True,
-        "attack_roll": attack,
-        "attack_bonus": 3,
-        "total": attack_total,
+        "attack_roll": {
+            key: value
+            for key, value in attack.items()
+            if key not in {"kind", "armor_class", "attack_bonus", "total", "hit"}
+        },
+        "attack_bonus": attack["attack_bonus"],
+        "total": attack["total"],
         "target_ac": ac,
-        "hit": hit,
+        "hit": attack["hit"],
         "damage": None,
     }
-    if hit:
+    if attack["hit"]:
         sheet, result["damage"] = _apply_chase_damage(
             sheet,
-            expression="1d6+1",
+            expression="2d6+1" if attack["critical"] else "1d6+1",
             damage_type="piercing",
             source="urban chase complication: overzealous guard spear",
             death_saves=death_saves,

packages/domain/tests/test_chase_engine.py

@@ -62,6 +62,28 @@ def _give_magic_resistance(actor: dict) -> None:
     actor["derived"] = derive_character_sheet(actor["sheet"])
 
 
+def _guard_chase(*, armor_class: int = 10) -> tuple[dict, dict]:
+    pursuer = _actor("pursuer", initiative=20)
+    quarry = _actor("quarry", initiative=10)
+    quarry["sheet"]["combat"]["ac"] = {
+        "base": armor_class,
+        "override": armor_class,
+    }
+    quarry["derived"] = derive_character_sheet(quarry["sheet"])
+    chase = start_chase(
+        [pursuer, quarry],
+        quarry_ids=["quarry"],
+        initial_distance_ft=100,
+    )
+    chase["turn_index"] = 1
+    chase["pending_complication"] = {
+        "number": 9,
+        "source_actor_id": "pursuer",
+        "rolled_round": 1,
+    }
+    return chase, quarry
+
+
 def test_module_close_transition_ends_chase() -> None:
     pursuer = _actor("pursuer", initiative=20)
     quarry = _actor("quarry", initiative=10)
@@ -207,21 +229,7 @@ def test_urban_complication_affects_next_participant() -> None:
 
 
 def test_urban_guard_attack_preserves_zero_armor_class() -> None:
-    pursuer = _actor("pursuer", initiative=20)
-    quarry = _actor("quarry", initiative=10)
-    quarry["sheet"]["combat"]["ac"] = {"base": 0, "override": 0}
-    quarry["derived"] = derive_character_sheet(quarry["sheet"])
-    chase = start_chase(
-        [pursuer, quarry],
-        quarry_ids=["quarry"],
-        initial_distance_ft=100,
-    )
-    chase["turn_index"] = 1
-    chase["pending_complication"] = {
-        "number": 9,
-        "source_actor_id": "pursuer",
-        "rolled_round": 1,
-    }
+    chase, quarry = _guard_chase(armor_class=0)
 
     result = advance_chase_turn(
         chase,
@@ -238,6 +246,57 @@ def test_urban_guard_attack_preserves_zero_armor_class() -> None:
     assert guard_attack["damage"]["total"] == 2
 
 
+def test_urban_guard_attack_applies_natural_one_and_ordinary_miss_rules() -> None:
+    natural_one_chase, quarry = _guard_chase(armor_class=0)
+    natural_one = advance_chase_turn(
+        natural_one_chase,
+        quarry,
+        actor_id_value="quarry",
+        action="move",
+        rng=_SequenceRng(1, 20),
+    )["turn"]["guard_attack"]
+
+    assert natural_one["attack_roll"]["fumble"] is True
+    assert natural_one["hit"] is False
+    assert natural_one["damage"] is None
+
+    ordinary_chase, quarry = _guard_chase(armor_class=10)
+    ordinary_miss = advance_chase_turn(
+        ordinary_chase,
+        quarry,
+        actor_id_value="quarry",
+        action="move",
+        rng=_SequenceRng(6, 20),
+    )["turn"]["guard_attack"]
+
+    assert ordinary_miss["attack_roll"]["fumble"] is False
+    assert ordinary_miss["total"] == 9
+    assert ordinary_miss["hit"] is False
+    assert ordinary_miss["damage"] is None
+
+
+def test_urban_guard_attack_natural_twenty_hits_and_doubles_the_damage_die() -> None:
+    chase, quarry = _guard_chase(armor_class=30)
+
+    result = advance_chase_turn(
+        chase,
+        quarry,
+        actor_id_value="quarry",
+        action="move",
+        rng=_SequenceRng(20, 3, 4, 20),
+    )
+
+    guard_attack = result["turn"]["guard_attack"]
+    assert guard_attack["attack_roll"]["critical"] is True
+    assert guard_attack["total"] == 23
+    assert guard_attack["target_ac"] == 30
+    assert guard_attack["hit"] is True
+    assert guard_attack["damage"]["expression"] == "2d6+1"
+    assert guard_attack["damage"]["rolls"] == [3, 4]
+    assert guard_attack["damage"]["total"] == 8
+    assert result["sheet"]["combat"]["hp"]["value"] == 12
+
+
 def test_urban_complication_incapacitation_prevents_movement() -> None:
     pursuer = _actor("pursuer", initiative=20)
     quarry = _actor("quarry", initiative=10)

packages/mcp/tests/test_chase_mcp.py

@@ -67,9 +67,17 @@ def test_public_chase_uses_exact_module_source_and_no_combat_map(
     )
     original_advance = server_module.advance_chase_turn
 
-    def deterministic_advance(*args, **kwargs):
-        kwargs["rng"] = _SequenceRng(20)
-        return original_advance(*args, **kwargs)
+    def deterministic_advance(chase, *args, **kwargs):
+        chase = {
+            **chase,
+            "pending_complication": {
+                "number": 9,
+                "source_actor_id": chase["quarry_ids"][0],
+                "rolled_round": 1,
+            },
+        }
+        kwargs["rng"] = _SequenceRng(20, 3, 4, 20)
+        return original_advance(chase, *args, **kwargs)
 
     monkeypatch.setattr(server_module, "advance_chase_turn", deterministic_advance)
 
@@ -346,6 +354,19 @@ async def exercise() -> None:
         )
 
         assert turn["turn"]["moved_ft"] == 60
+        guard_attack = turn["turn"]["guard_attack"]
+        assert guard_attack["attack_roll"]["critical"] is True
+        assert guard_attack["hit"] is True
+        assert guard_attack["damage"]["expression"] == "2d6+1"
+        assert guard_attack["damage"]["rolls"] == [3, 4]
+        assert guard_attack["damage"]["total"] == 8
+        assert turn["status"] == "committed"
+        assert turn["character"]["sheet"]["combat"]["hp"]["value"] == 12
+        assert turn["character"]["revision"] == current_pursuer["revision"] + 1
+        assert any(
+            receipt["mechanic_id"] == "dnd5e.core.chase.urban_complications"
+            for receipt in turn["rule_receipts"]
+        )
         assert turn["chase"]["active"] is False
         assert turn["chase"]["outcome"]["status"] == "destination_reached"
         queried = await _call(