dndwright 0.2.0

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).

dndwright

⚠️ Early development (v0.1, alpha). The API is still moving and may change without notice between minor versions. Extracted from a working application; usable today, but pin a tag/commit if you depend on it.

A domain-neutral D&D 5e (2024) rules & character-sheet computation engine. A character sheet is modelled as a directed acyclic computation graph — nodes are values, edges are dependencies, and formulas are data (a JSON-serialisable DSL), not code. Pure Python (pydantic + stdlib), no application or framework coupling: map your own character data in, read computed stats out.

Install

pip install git+https://github.com/sligara7/dndwright.git
# or, for local development:
pip install -e ".[dev]"

Quickstart

from dndwright import evaluate_character

sheet = evaluate_character({
    "ability_scores": {"strength": 8, "dexterity": 14, "constitution": 14,
                       "intelligence": 18, "wisdom": 12, "charisma": 10},
    "class_data": {"class_name": "wizard"},
    "species_data": {"name": "Human", "speed": 30},
    "level": 5,
})

sheet["proficiency_bonus"]    # 3
sheet["ability_modifiers"]    # {"intelligence": 4, "dexterity": 2, ...}
sheet["spellcasting_type"]    # "full_caster"
# ...plus armor_class, hit_points, hit_dice, initiative, saves, features, ...

Lower level — assemble typed inputs and evaluate against the ruleset:

from dndwright import DND_5E_2024_RULESET, assemble_character_inputs, evaluate, apply_modifiers
from dndwright.rules.components import ClassMechanics

inputs   = assemble_character_inputs(class_mechanics=..., ability_scores={...}, level=5)
computed = apply_modifiers(evaluate(DND_5E_2024_RULESET, inputs), inputs)

Why a computation graph?

Derived character values form a dependency DAG: ability scores → modifiers → proficiency → save DCs / spell slots / AC / HP. dndwright represents that DAG explicitly and stores the formulas as data (FormulaSpec: an op + args), so the rules are inspectable, testable, and serialisable — not buried in imperative code. DND_5E_2024_RULESET is a 135-node graph.

What's inside

Component	What it does
evaluate_character	One call: character data dict → fully computed sheet.
DND_5E_2024_RULESET	The 135-node 5e-2024 computation DAG (formulas as data).
evaluate / assemble_character_inputs / apply_modifiers	The lower-level engine.
Ruleset / ComputationNode / FormulaSpec / NodeType	The DAG schema.
dndwright.rules.components	Typed inputs (ClassMechanics, SpeciesMechanics, …).
dndwright.rules.lookup_tables	SRD-derived rules tables (hit dice, spell slots, AC, saves).

API stability

The public API is exactly dndwright.__all__, pinned by tests/test_api_contract.py. Versioning follows SemVer; at 0.x minor versions may break, with every change recorded in CHANGELOG.md.

Credits & license

MIT licensed (see LICENSE). The rules tables encode game mechanics derived from the D&D System Reference Document 5.2 (© Wizards of the Coast, CC-BY-4.0); see NOTICE. Not affiliated with or endorsed by Wizards of the Coast. Contains no PHB/DMG/MM content.