feat(rules): conform bulls strength, bears endurance and shield to the SRD

Bull's Strength now grants the SRD +4 enhancement bonus to Strength as
+2 melee attack, +2 melee damage and +2 CMB (three modifiers instead of
the previous +1/+1 approximation). Shield now uses a real shield bonus
type (+4 AC) instead of approximating it as deflection: the engine's
BonusType literal and stacking docs gain the shield type, which stays
out of the CMD bonus list (SRD Combat Maneuver Defense). Bear's
Endurance keeps its +2 Fortitude / +2 hp per HD and its description now
cites the SRD and flags the hp modifier as informational. Golden
transcripts updated: the buff log reports 3 mods and Tammara's pistol
attacks gain the extra +1 enhancement (d20=10+9-6=15).

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

data/spells/bears_endurance.json

@@ -16,5 +16,5 @@
       "duration_rounds": 60
     }
   ],
-  "description": "The subject gains a +4 enhancement bonus to Constitution, granting +2 Fortitude and +2 hit points (approximated as +2/+2). Fortitude negates (harmless). Duration 10 min/level approximated as 60 rounds."
+  "description": "The subject gains a +4 enhancement bonus to Constitution, granting +2 to Fortitude saves and +2 hit points per Hit Die (SRD bear's endurance; the hp modifier is informational — the engine has no per-HD hp pool). Will negates (harmless). Duration 10 min/level approximated as 60 rounds."
 }

data/spells/bulls_strength.json

@@ -10,11 +10,12 @@
     {
       "type": "buff",
       "modifiers": [
-        { "target": "attack", "value": 1, "bonus_type": "enhancement" },
+        { "target": "attack", "value": 2, "bonus_type": "enhancement" },
-        { "target": "damage", "value": 1, "bonus_type": "enhancement" }
+        { "target": "damage", "value": 2, "bonus_type": "enhancement" },
+        { "target": "cmb", "value": 2, "bonus_type": "enhancement" }
       ],
       "duration_rounds": 60
     }
   ],
-  "description": "The subject gains a +4 enhancement bonus to Strength, granting +2 attack and +2 damage (approximated as +1/+1). Fortitude negates (harmless)."
+  "description": "The subject gains a +4 enhancement bonus to Strength, granting +2 to melee attack rolls, melee damage rolls, and combat maneuver checks (SRD bull's strength). Will negates (harmless)."
 }

data/spells/shield.json

@@ -10,10 +10,10 @@
     {
       "type": "buff",
       "modifiers": [
-        { "target": "ac", "value": 4, "bonus_type": "deflection" }
+        { "target": "ac", "value": 4, "bonus_type": "shield" }
       ],
       "duration_rounds": 10
     }
   ],
-  "description": "An invisible shield of force hovers in front of you, granting a +4 shield bonus to AC for 1 min./level (modeled as 10 rounds; the shield bonus type is approximated as deflection since the engine has no shield bonus type). Negating magic missile and the ranged-attack deflection are not modeled."
+  "description": "An invisible shield of force hovers in front of you, granting a +4 shield bonus to AC for 1 min./level (modeled as 10 rounds). Negating magic missile and the ranged-attack deflection are not modeled."
 }

src/pf1e_simulator/effects.py

@@ -3,7 +3,8 @@
 PF1e bonus types determine whether multiple bonuses to the same stat stack:
 - Stacking types (dodge, racial, trait, untyped/"") all sum together.
 - Non-stacking types (morale, sacred, profane, competence, insight, luck,
-  enhancement, deflection, natural) keep only the highest value per type.
+  enhancement, deflection, natural, shield) keep only the highest value per
+  type.
 - Penalties follow the same rules: same-type penalties don't stack (the
   least severe — i.e. the max value — is kept).
 
@@ -36,6 +37,7 @@ BonusType = Literal[
     "enhancement",    # no stack
     "deflection",     # no stack
     "natural",        # no stack
+    "shield",         # no stack
     "circumstance",   # no stack (simulator can't distinguish circumstances)
 ]
 

tests/test_pc_combat_golden.py

@@ -64,28 +64,28 @@ class TestGoldenCombats:
         assert result.transcript == (
             "initiative: tammara d20=15+7=22",
             "initiative: goblin d20=10+6=16",
-            ("round 1 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 2 mods (60r) "
+            ("round 1 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 3 mods (60r) "
              "(36->36)"),
             "round 1 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            ("round 2 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 2 mods (60r) "
+            ("round 2 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 3 mods (60r) "
              "(36->36)"),
             "round 2 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            ("round 3 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 2 mods (60r) "
+            ("round 3 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 3 mods (60r) "
              "(36->36)"),
             "round 3 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 4 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 4 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 4 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 5 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 5 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 5 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 6 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 6 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 6 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 7 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 7 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 7 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 8 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 8 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 8 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            "round 9 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 -> MISS",
+            "round 9 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 -> MISS",
             "round 9 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
-            ("round 10 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=14 AC 16 "
+            ("round 10 tammara: Braises d'Automne (pistolet ?) vs goblin d20=10+9-6=15 AC 16 "
              "-> MISS"),
             "round 10 goblin: short bow vs tammara d20=15+4-2=17 AC 20 -> MISS",
             "battle over: draw after 10 rounds",
@@ -106,7 +106,7 @@ class TestGoldenCombats:
         assert result.transcript == (
             "initiative: tammara d20=15+7=22",
             "initiative: lich d20=10+6=16",
-            ("round 1 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 2 mods (60r) "
+            ("round 1 tammara: cast Bull's Strength vs tammara DC15 SAVED -> buff 3 mods (60r) "
              "(36->36)"),
             "round 1 lich: cast Magic Missile vs tammara DC16 NO SAVE -> 43 damage (36->-7)",
             "battle over: monsters win in 1 rounds",

tests/test_spells.py

@@ -193,7 +193,9 @@ class TestSpellLoading:
         spell = load_spell(_SPELLS_DIR / "bulls_strength.json")
         eff = spell.effects[0]
         assert isinstance(eff, BuffEffect)
-        assert len(eff.modifiers) == 2
+        # SRD bull's strength: +4 enhancement Str -> +2 melee attack, +2 melee
+        # damage, +2 CMB (three modifiers).
+        assert len(eff.modifiers) == 3
 
     def test_summon_monster_casts_for_one_round(self) -> None:
         # PF1e: Summon Monster I/II have a 1-round casting time.
@@ -616,10 +618,13 @@ class TestBullsStrength:
         buff_mods = [m for b in t.active_buffs for m in b.modifiers]
         atk_mods = [e for e in buff_mods if e.target == "attack"]
         dmg_mods = [e for e in buff_mods if e.target == "damage"]
+        cmb_mods = [e for e in buff_mods if e.target == "cmb"]
         assert len(atk_mods) == 1
         assert len(dmg_mods) == 1
-        assert atk_mods[0].value == 1
+        assert len(cmb_mods) == 1
-        assert dmg_mods[0].value == 1
+        assert atk_mods[0].value == 2
+        assert dmg_mods[0].value == 2
+        assert cmb_mods[0].value == 2
 
     def test_transcript_shows_buff(self) -> None:
         caster = _make_caster()