fix(rules): Toughness is +3 hp below 4 Hit Dice (max(3, level))

src/pf1e_simulator/abilities.py

@@ -49,16 +49,16 @@ def weapon_focus(weapon_name: str) -> AbilitySpec:
     )
 
 
-# Toughness: +1 HP per Hit Die (approximated as +level HP, untyped, CRB)
-# For simplicity at this stage, we model it as a flat HP bonus.
-# The engine doesn't yet compute per-HD bonuses, so the caller sets the value.
+# Toughness (CRB): "+3 hit points. If the character has 4 or more Hit Dice,
+# she gains +1 hit point per Hit Die." => max(3, HD). The engine doesn't yet
+# compute per-HD bonuses, so the caller passes the level.
 def toughness(level: int) -> AbilitySpec:
     return AbilitySpec(
         name="Toughness",
         category="feat",
         source_detail="feat lv1",
         effects=(
-            StatModifier(target="hp", value=level),
+            StatModifier(target="hp", value=max(3, level)),
         ),
     )
 

tests/test_feats.py

@@ -135,6 +135,21 @@ def test_spot_check_toughness_level_tied() -> None:
     assert any(e.value == 5 for e in spec.effects)
 
 
+def test_toughness_is_plus3_below_four_hd_and_plus_hd_above() -> None:
+    # CRB Toughness: "+3 hit points. If the character has 4 or more Hit
+    # Dice, she gains +1 hit point per Hit Die."
+    def hp_value(level: int) -> int:
+        spec = _resolve_feat("Toughness", level)
+        values = [e.value for e in spec.effects if e.target == "hp"]
+        assert len(values) == 1
+        return values[0]
+
+    assert hp_value(1) == 3
+    assert hp_value(2) == 3
+    assert hp_value(3) == 3
+    assert hp_value(4) == 4
+
+
 # ── Expected mapping table (name -> resolved display name or traced-no-op) ─────
 
 _EXPECTED_RESOLUTION: dict[str, str] = {