fix: hit-die display desync + species natural armor AC

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 0.25.1
+
+### Fixed
+- Hit-die compute/display desync: the displayed hit die now matches the archetype/class override used for HP computation (was showing the raw LLM value).
+- Species natural armor now contributes to AC via a `natural_armor_ac` computation-graph input; AC = max(natural, equipped + dex + magic + shield) per 5e.
+
+
 All notable changes to dndwright are documented here. The format follows
 [Keep a Changelog](https://keepachangelog.com/), and the project aims to follow
 [Semantic Versioning](https://semver.org/).

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "dndwright"
-version = "0.25.0"
+version = "0.25.1"
 description = "Domain-neutral D&D 5e (2024) rules & character-sheet computation engine: a data-driven DAG of formulas (ability mods, proficiency, spell DC/slots, HP, AC)."
 readme = "README.md"
 requires-python = ">=3.10"

src/dndwright/rules/adapters.py

@@ -18,6 +18,67 @@
     SPELLCASTING_TYPE_BY_CLASS,
 )
 
+import re
+
+
+import re
+
+
+def _resolve_hit_die(class_data: dict) -> int:
+    """Return the resolved hit die size, applying lookup-table overrides.
+
+    Mirrors the logic in ``character_data_to_inputs`` lines 51-58 so the display
+    value matches the computation.
+    """
+    hit_die_str = class_data.get("hit_die", "d8")
+    hit_die_size = int(hit_die_str.replace("d", "")) if isinstance(hit_die_str, str) else 8
+
+    class_name = class_data.get("class_name", "").lower()
+    archetype = (
+        class_data.get("archetype")
+        or class_data.get("properties", {}).get("archetype", "")
+    )
+    if class_name in HIT_DIE_BY_CLASS:
+        hit_die_size = HIT_DIE_BY_CLASS[class_name]
+    elif archetype in HIT_DIE_BY_ARCHETYPE:
+        hit_die_size = HIT_DIE_BY_ARCHETYPE[archetype]
+
+    return hit_die_size
+
+
+_NATURAL_ARMOR_KEYWORDS = re.compile(
+    r"(carapace|natural armor|chitin|exoskeleton|scales|tough hide|bark skin|"
+    r"thick fur|bony plates|armored shell)",
+    re.IGNORECASE,
+)
+_AC_VALUE_RE = re.compile(r"\bAC\b.*?(\d+)", re.IGNORECASE)
+
+
+def _parse_natural_armor(species_data: dict) -> int:
+    """Extract natural armor AC from species traits, or 0 if none."""
+    # Explicit field (future-proof)
+    explicit = species_data.get("natural_armor_ac")
+    if isinstance(explicit, int) and explicit > 0:
+        return explicit
+
+    traits: list[dict] = species_data.get("traits", []) or []
+    if not isinstance(traits, list):
+        return 0
+
+    for trait in traits:
+        if not isinstance(trait, dict):
+            continue
+        name = (trait.get("name") or "").lower()
+        desc = (trait.get("description") or "").lower()
+        combined = name + " " + desc
+
+        if _NATURAL_ARMOR_KEYWORDS.search(combined):
+            match = _AC_VALUE_RE.search(combined)
+            if match:
+                return int(match.group(1))
+
+    return 0
+
 
 def character_data_to_inputs(
     ability_scores: dict[str, int],
@@ -86,6 +147,9 @@ def character_data_to_inputs(
     inputs["armor_magic_bonus"] = armor_magic
     inputs["has_shield"] = has_shield
 
+    # --- Species natural armor ---
+    inputs["natural_armor_ac"] = _parse_natural_armor(species_data)
+
     # --- Spellcasting ---
     spellcasting_type = class_data.get("properties", {}).get("spellcasting_type") or class_data.get(
         "spellcasting_type", "none"
@@ -227,7 +291,8 @@ def _fmt(val: int | None) -> str:
         speed_val = speed
 
     # --- Hit dice ---
-    hit_die = class_data.get("hit_die", "d8")
+    hit_die_size = _resolve_hit_die(class_data)
+    hit_die = f"d{hit_die_size}"
     hit_dice_str = computed.get("hit_dice", f"{level}{hit_die}")
 
     # --- Spellcasting ---

src/dndwright/rules/assembler.py

@@ -153,6 +153,7 @@ def assemble_character_inputs(
         inputs["armor_type"] = "none"
         inputs["armor_magic_bonus"] = 0
     inputs["has_shield"] = has_shield
+    inputs["natural_armor_ac"] = 0
 
     # ------------------------------------------------------------------
     # 8. Saving throw proficiencies

src/dndwright/rules/dnd_5e_2024.py

@@ -182,6 +182,20 @@ def add(node: ComputationNode) -> None:
         )
     )
 
+    add(
+        ComputationNode(
+            id="natural_armor_ac",
+            node_type=NodeType.INPUT,
+            label="Natural Armor AC",
+            layer=0,
+            group="equipment",
+            default_value=0,
+            min_value=0,
+            max_value=30,
+            description="Base AC from species natural armor (0 = none).",
+        )
+    )
+
     add(
         ComputationNode(
             id="speed_base",
@@ -446,9 +460,9 @@ def add(node: ComputationNode) -> None:
             group="combat",
             formula=FormulaSpec(
                 op="ac_with_armor",
-                args=["armor_type", "dexterity_mod", "armor_magic_bonus", "has_shield"],
+                args=["armor_type", "dexterity_mod", "armor_magic_bonus", "has_shield", "natural_armor_ac"],
             ),
-            inputs=["armor_type", "dexterity_mod", "armor_magic_bonus", "has_shield"],
+            inputs=["armor_type", "dexterity_mod", "armor_magic_bonus", "has_shield", "natural_armor_ac"],
             min_value=1,
             description="Base AC from armor + DEX (capped) + magic + shield. PHB p.14.",
         )

src/dndwright/rules/operations.py

@@ -172,15 +172,17 @@ def op_multiclass_hp(args: list[Any], _tables: dict) -> int:
 
 
 def op_ac_with_armor(args: list[Any], tables: dict) -> int:
-    """Compute AC from armor type + dex mod.
+    """Compute AC from armor type + dex mod + natural armor.
 
-    args: [armor_type, dex_mod, magic_bonus, has_shield]
+    args: [armor_type, dex_mod, magic_bonus, has_shield, natural_armor_ac]
     Uses lookup tables: armor_base_ac, armor_max_dex
+    AC = max(natural_armor_ac, armor_base_ac + dex(capped) + magic + shield) per 5e.
     """
     armor_type = str(args[0]).lower().replace(" ", "_") if args[0] else "none"
     dex_mod = int(args[1])
     magic_bonus = int(args[2]) if len(args) > 2 else 0
     has_shield = bool(args[3]) if len(args) > 3 else False
+    natural_armor_ac = int(args[4]) if len(args) > 4 else 0
 
     armor_base_ac = tables.get("armor_base_ac", {})
     armor_max_dex = tables.get("armor_max_dex", {})
@@ -199,7 +201,7 @@ def op_ac_with_armor(args: list[Any], tables: dict) -> int:
     if has_shield:
         ac += 2
 
-    return ac
+    return max(natural_armor_ac, ac)
 
 
 def op_spell_slots(args: list[Any], tables: dict) -> dict[str, int]: