Axiomancer — Mechanics Engine

Turn-based RPG engine with a Heart / Body / Mind combat system. Status effects, skills, and enemies are themed around logical fallacies and philosophical paradoxes.

This repository is the non-UI engine only. It is consumed as a library by clients (e.g. a React Native app). All logic is exposed through the package barrel at src/index.ts.

Looking for a tour? See docs/quickstart.md — a single-page entry point covering what's shipped, how to drive the CLI through every major surface, the walkthrough catalog, key in-game flows (combat / friendship path / map exploration / save-load), verify gates, and pointers to deeper docs.

See VISION.md for T's current game vision and doctrine guardrail before major mechanics, combat, friendship, balance, or /march work.

See RELEASES.md for short-form per-version summaries (at-a-glance "what shipped in 0.X.Y?"), CHANGELOG.md for the full per-phase detail per release, RELEASING.md for the publish flow + deprecation lifecycle policy, docs/source-of-truth-hierarchy.md for Nexus state reconciliation law, and docs/adr/ for durable architecture and product decisions that govern mechanics work.

Install

The package is published to npm:

npm install axiomancer-mechanics

For local engine development:

npm install
npm run build       # compiles to ./dist

Quick start

import {
  createCharacter, createEnemy,
  createGameStore, nullAdapter,
  determineEnemyAction, determineAdvantage,
  applyDamage, getAttackStat, getDefenseStat,
  applyTier1CombatEffect, lookupEffect,
  isCombatOngoing,
} from 'axiomancer-mechanics';

const player = createCharacter({
  name: 'Hero',
  level: 1,
  baseStats: { heart: 4, body: 3, mind: 2 },
});

const enemy = createEnemy({
  id: 'goblin-1',
  name: 'Goblin',
  description: '',
  level: 1,
  baseStats: { heart: 1, body: 2, mind: 1 },
  mapName: 'fishing-village',
  logic: 'random',
});

const store = createGameStore(nullAdapter, { player });
store.getState().startCombat(enemy);

while (isCombatOngoing(store.getState().combat!)) {
  // ...drive a round of combat using the helpers above...
}

Public API

The barrel exports are organised by domain:

| Group | Highlights | | --------------- | ------------------------------------------------------------------------------------------------------------ | | Character | createCharacter (auto-generates Character.id via getRng() when not supplied — Phase 35), equipItem/unequipItem, getEquipmentModifiers, allocateStatPoint + STAT_POINTS_PER_LEVEL + availableStatPoints field on Character (Phase 29), presets API (characterPresets, getPresetById, buildCharacterFromPreset), types (Character, BaseStats, DerivedStats, NonCombatStats, CharacterPreset) | | Enemy | createEnemy, decideEnemyAction, AI presets (aggressive/defensive/balanced/strategic/bossLogic), rollLoot/rollLootMany, EnemyLibrary, EnemiesByMap, ENEMY_REGISTRY, DEFAULT_XP_BY_DIFFICULTY; Enemy.philosophicalAlignment?: PhilosophicalAlignment + outlook-driven basic-action bias since Phase 45; per-enemy friendshipReward?: FriendshipReward ({ items?, xpBonus?, narrative?, flagSet?, alignmentDelta? }) drives Phase 60 befriendable-enemy content (MournfulGull + HollowEyedBeggar authored today). Phase 62 added flagSet?: string — appends a world flag to state.flags on friendship outcome, consumed by DialogueChoice.requires.flag. Phase 68 added BefriendabilityConfig + Enemy.befriendabilityConfig?: BefriendabilityConfig — per-enemy override of the Phase 36 friendship-eligibility check (roundsThreshold / hpGate / requiredStances / requiredSkillUse AND-composed; defaultFallback escape hatch). First boss-tier authored config: CoastalTyrant (hpGate { belowPct: 0.4 }, requiredStances: ['heart'], roundsThreshold: 5). Phase 69 added alignmentDelta?: Partial<PhilosophicalAlignment> — applied to state.philosophicalAlignment via applyAlignmentDelta on friendship outcome; the post-clamp value surfaces on CombatEndReport.friendshipReward.alignmentShift. Closes Spec 14 Q4. First authored deltas: MournfulGull { outlook: +3 }, HollowEyedBeggar { scope: -3 }. Phase 71 added FinalBlowLines / PactLines / CauseLines types + per-foe finalBlowLines? / pactLines? / causeLines? — chronicle-voice prose on the Enemy type for the post-combat aftermath panel (3 variants per group; consumer picks based on outcome shape). Closes GH#65 ask 1. Initial author coverage: MournfulGull, HollowEyedBeggar, CoastalTyrant. Phase 73 added CodexEntry { id, title, body } type + per-foe journalEntry?: CodexEntry — auto-unlocks on outcome === 'friendship' (appends to state.codex.unlockedEntries; surfaces { id, title } on CombatEndReport.friendshipReward.codexEntryUnlocked). Initial entries: codex-mournful-gull, codex-hollow-eyed-beggar, codex-coastal-tyrant. Closes GH#65 ask 3. | | Combat | determineAdvantage, stat accessors (getBaseStat/getAttackStat/getDefenseStat/getSaveStat), applyDamage/heal/healCharacter, tickAllEffects/applyRegen, getActiveRollModifier/getThornsReflect, resolveEffectApplication (Phase 80 — Tier 2 debuff + Tier 3 always land; target-resist roll removed), determineCombatEnd, isCombatOngoing, Stance/Action/CombatState/Combatant | | Combat reducer | initializeCombat, setPhase/setPlayerStance/setPlayerAction, appendLog, incrementFriendship, endCombat. Deprecated (@deprecated JSDoc — scheduled for removal at the next minor bump): endCombatPlayerVictory / endCombatPlayerDefeat / endCombatWithFriendship — all three dispatch to endCombat; the outcome is computed by determineCombatEnd(state), not by the function name | | Combat resolver | resolveCombatRound plus its typed event stream: RoundResolution, CombatActor, RoundEvent (RoundStartEvent, ActionRestrictionEvent, AdvantageEvent, StanceEffectEvent, ScenarioEvent, SkillPhaseEvent, ResourceEvent, ItemPhaseEvent, RoundEndEvent). Per-phase implementation under Combat/phases/ since Phase 15. | | Hazard-Pattern Combat (Spec 25) | Card-and-dice combat engine that ships alongside resolveCombatRound — every verb is a combat card (projected from a learned skill), and HP is the sole win condition (enemy HP drops to 0 via DoT erosion + strikes; basic-attack trading is the weak baseline). Drive a fight with initializeCombatEncounter, rollEncounterDice, playCombatCard, resolveCombatPhase/resolveThreatPhase/processBetweenPhases, buildCombatSummary; preview helpers getCard/handCards/cardDieCostPreview/availableDice; dice/deck/card/threat sub-modules (rollCombatDice, buildCombatDeck, toCombatCard, getThreatSequence); Monte-Carlo greedy bot simulateHazardPatternCombat. Types: CombatEncounterState, CombatCard, CombatThreatPhase, CombatOutcome, CombatSummary, CombatSimStats. See docs/combat.md → Hazard-Pattern Combat. | | Effects | applyEffect, applyTier1CombatEffect, clearTier1EffectsForStance/ForType, lookupEffect/getEffectByName/getEffectsByType, effectsLibrary, processWorldEffectTick/getActiveHazards, types (Effect, ActiveEffect, EffectTier, StatModifier, DamageOverTime, RegenerationConfig, ActiveHazard). Phase 80 always-land contract: Tier 2 debuffs + Tier 3 always land (no resist roll); only Tier 2 buff caster fumble/crit survives. See docs/effects.md. | | Items | addItem/removeItem/stackItem, useConsumable/useConsumableEffect, equipment helpers (aggregateCombatStartTokens, applyEquipmentGenerationBonus, getEquipmentProcTriggers), equipmentTemplates/uniqueTemplates, consumableLibrary, type guards; shop economy (buyItem/sellItem/defaultSellPrice, types ShopWare/ShopInventory — Phase 37 + iterate 3ba5319); set items (getActiveSetBonuses + 5 siblings: getActiveSetBonusesForCharacter/aggregateSetStartTokens/applySetGenerationBonus/getActiveSetPassiveEffectIds/getEquippedItemSets, library itemSetLibrary/getItemSetById, types SetBonus/ItemSet — Phase 54); base types (Item, Equipment, Consumable, Material, QuestItem, EquipmentTemplate, UniqueItemTemplate); Phase 75 added previewTemplateAtRarity(templateId, rarity, playerLevel, rng?): Equipment \| undefined — UI-tier wrapper around dropItem for mobile item-library mod-visibility (closes the user-jot at b5c8165). Phase 76 added previewTemplateAtAllRarities(templateId, playerLevel, rng?): Record<ItemRarity, Equipment \| undefined> — batch wrapper around the Phase 75 single-cell helper for UI tooltip / item-detail views rendering the full rarity strip in one call. Phase 152 added the affix-naming layer: dropItemWithAffixes(templateId, playerLevel, rng?, opts?: DropWithAffixesOptions) (drop + prefix/suffix roll), composeItemName, the prefixes/suffixes/allAffixes libraries with getAffixById/affixesForSlot lookups, AFFIX_RARITY_WEIGHTS draw scale, and types (DropWithAffixesOptions, AffixControl, Affix, AffixRole). | | Skills | executeSkill, canUseSkill/spendResources/calculateSkillDamage, generateBasicActionResources/generatePhilosophicalResource, runtime learning (learnSkill, getAvailableSkills, meetsLearningRequirement — Phase 30; learningRequirement field on every Tier 2 / Tier 3 entry — Phase 33), top-level skill library (skillLibrary/getSkillById — Phase 50 unit 1 engine-handoff fix), types (Skill, CombatResources, SkillTier, SkillResolution, SkillEvent, SkillLookup); Tier 2 synergy primitive (SkillSynergy + SynergyPredicate types; 5 authored skills — resonance-bleed/intensity-feedback/bat-swarm-thoughtform/resonance-burst/resonance-detonation — Phase 66) | | Game | createGameStore/createNewGameState, gameReducer/migrate, createEventEmitter, selectors (selectPlayer, selectCombat, selectInventory, selectMoralMeter, selectVersion), nullAdapter (Node adapter createNodeAdapter lives on 'axiomancer-mechanics/node' since Phase 21), mechanic constants (FRIENDSHIP_COUNTER_MAX, MAX_EFFECT_DURATION, PASSIVE_DEFENSE_MULTIPLIER, STAT_POINTS_PER_LEVEL, …), GameAction union extended with ALLOCATE_STAT_POINT (Phase 29) and LEARN_SKILL (Phase 30), typed event surface (EnginePayload with optional unlockedSkills on character:levelup per Phase 30 unit 2 and combatEvents on combat:round per iterate 5ac6caa, TypedGameEvent + 10 per-topic aliases, 10 is*Event guards), types (GameState, GameStore, GameAction, GameEvent/GameEventEmitter, PersistenceAdapter); GameState.lastSeenAlignmentCells?: Record<string, string> (Phase 63 — Beta; per-tree observer cache); Phase 72 added run-loop semantics — store.resetRun({ keepCharacter: bool }) + required GameState.runId: string (16-char hex; bumped per reset) + generateRunId helper + STARTING_REGION constant; GAME_STATE_VERSION bumped 5 → 6 with migrateV5toV6 defaulting runId for legacy saves. Closes GH#65 ask 2. Phase 73 added CodexState + required GameState.codex: CodexState slice + store.unlockCodexEntry(entryId) + UNLOCK_CODEX_ENTRY action + auto-firing wire on friendship outcomes; GAME_STATE_VERSION bumped 6 → 7 with migrateV6toV7 defaulting codex for legacy saves. Closes GH#65 ask 3. | | World | createStartingWorld, world reducer (changeMap/completeMap/unlockMap/completeNode/unlockNode/changeContinent, plus Phase-23 revealAdjacent/markNodeConsumed and Phase-31 unlockAdjacent), map registry (MAP_REGISTRY, getMapDefinition, createMapState), node traversal (moveToNode, completeCurrentNode, applyDialogueChoice), MapEvents engine (resolveMapEvent, registerMapEventPool, setDefaultMapEventPool, setNodeEventPoolOverride, types: MapEventKind, MapEventPool, ResolvedEvent, etc.; the legacy processNode + MapEvent / MapEventType surface was removed in Phase 25), quests (emptyQuestLog, startQuest/progressQuest/completeQuest/discoverQuest; reach-objective auto-advance restored at iterate 8611881), encounters (generateEncounter, scaleEnemyToLevel, DIFFICULTY_LEVEL_BANDS), types (WorldState, MapState, MapDefinition, MapNode, Quest, Encounter) | | NPCs | getDialogueNode, visibleChoices, isLeafNode, types (NPC, DialogueMap, DialogueTree, DialogueNode, DialogueChoice, DialogueContext); DialogueChoice.effect.alignmentDelta?: Partial<PhilosophicalAlignment> since Phase 43. Phase 63 added the alignment-observer machinery: DialogueTree.id?: string (opts a tree into the cache), DialogueChoice.requires.playerAlignmentCellChangedSince?: boolean (reactive gate), DialogueContext.lastSeenAlignmentCellId?: string (caller-sourced input) | | Philosophy | 3-axis alignment cube + 27-cell content registry. Engine: bucketAxis/getAlignmentCell/applyAlignmentDelta/defaultAlignment, constants (AXIS_HIGH_THRESHOLD, AXIS_LOW_THRESHOLD), library (philosophicalAlignmentLibrary — 27 entries, each carrying philosopher + literary character + 3 fallacies). Types (PhilosophicalAlignment, AxisBucket, AlignmentFallacy, PhilosophicalAlignmentCell). State: GameState.philosophicalAlignment (Phase 42, GAME_STATE_VERSION 5 with migrateV4toV5), SHIFT_PHILOSOPHICAL_ALIGNMENT action + store action. Authoring surfaces: DialogueChoice.effect.alignmentDelta + MapEventPoolEntry.alignmentDelta (Phase 43). Live content: 4 Tier 3 fallacy skills (appeal-to-consequences, nirvana-fallacy, pascals-wager, appeal-to-fear) + 3 fallacy status effects (debuff_no_true_scotsman, buff_special_pleading, debuff_category_error) via sourcedFromCell?: string cross-link on Skill + Effect (Phase 44). Enemy alignment + outlook AI bias (Phase 45). Alignment gates: AlignmentGate type ({ axis, op: 'gte'\|'lte', value }), DialogueChoice.requires.requiresAlignment? + SkillLearningRequirement.requiresAlignment?, optional alignment param on meetsLearningRequirement / getAvailableSkills / learnSkill, DialogueContext.alignment? (Phase 46). See docs/philosophy.md. | | Utils | clamp/inRange/average/sum/max/min, randomInt, deepClone, capitalize/formatPercent, createDie/createDieRoll/determineRollAdvantageModifier, deriveStats/deriveNonCombatStats/calculateMaxHealth, type guards (isCharacter, isEnemy, isCombatActive) | | Utils — RNG | getRng/setRng/setSeed, Rng interface (seedable LCG; Phase 11 routed all gameplay rolls through this singleton so saves are reproducible) |

Recent infrastructure (Phases 81-88): 13 agent-graded walkthroughs in automation/scripts/walkthroughs/ (Phase 81); CLI codex + reset tabs (Phase 82); 824 hermetic tests (Phase 83 skill coverage + Phase 88 effect coverage sweep); 5 per-module quickstart pages at docs/quickstart-*.md (Phase 87).

Hazard public API

[email protected] ships the Hazard minigame through the top-level barrel. Consumers can import initializeHazard, drawOpeningHand, selectRoute, rollDiceAndStartRound, playCardInRound, resolveRound, advanceToNextRound, computeFinalScore, HAZARD_CARD_LIBRARY, ACTION_CARD_LIBRARY, STARTER_DECK_CARD_IDS, and Hazard types such as HazardMinigameState, HazardCard, HazardActionCard, HazardManaDie, and HazardRoundResult. See docs/hazard-minigame-api.md.

CLIs

The repo also ships a hands-on demo CLI. It is NOT part of the published package surface (src/CLI is excluded from the build):

| Command | What it does | | ---------------- | ----------------------------------------------------------------------------- | | npm run game | Interactive demo — tabbed map / combat / journal / skills / inventory loop. |

Agent-driven CLI mode

npm run game accepts three flags so the demo loop can be driven without a human at the keyboard:

| Flag | What it does | | ---- | ------------ | | --script <path> | Loads a JSON array of answer objects and feeds them to subsequent prompts in order. Each object matches the shape inquirer.prompt returns (e.g. {"presetId": "apprentice"}, {"tab": "debug"}). Exhaustion throws. | | --stdin | Reads one JSON object per line from stdin and uses each as the next answer. EOF before all prompts complete throws. | | --json-events | Replaces the human event log with one JSON.stringify(event) line per emitted GameEvent on stdout. Human prose is routed to stderr so stdout stays machine-clean. A final {"type":"cli:exit",...} line marks the end. | | --state-log <path> | Appends one JSON-line record per state mutation ({ tick, action, before, after, event? }). Used by the agent-graded harness below. (Phase 26) |

Examples:

npm run game -- --script replay.json --json-events
echo '{"presetId":"apprentice"}' | npm run game -- --stdin --json-events
npm run game -- --script walkthrough.json --json-events --state-log run.jsonl

--script and --stdin are mutually exclusive; if both are passed, --script wins.

Agent-graded e2e (Phase 26)

automation/agent-e2e.mjs runs a scripted walkthrough against the CLI, captures the state log + event stream + stderr, and asks the Claude API to decide whether the test goal was achieved. Useful when the UI isn't built yet and you want to verify a CLI surface end-to-end.

ANTHROPIC_API_KEY=sk-ant-... \
npm run agent-e2e -- automation/scripts/walkthroughs/character-sheet.json \
                     automation/scripts/walkthroughs/character-sheet.goal.md

The harness exits 0 on pass, 1 on fail. The default grading model is claude-sonnet-4-6; override with AGENT_MODEL. This layer is deliberately non-hermetic — it phones the Anthropic API. The hermetic vitest suite stays in src/**/e2e/*.engine.test.ts and never makes network calls.

Each walkthrough under automation/scripts/walkthroughs/ has a paired *.goal.md describing what success looks like in human terms.

Project layout

src/
  index.ts                 # public barrel
  Character/               # createCharacter + Character types
  Combat/                  # advantage, stats, dice, damage, health, effects, resist, reducer
  Effects/                 # applyEffect, Tier 1 stance effects, library lookup
  Enemy/                   # createEnemy + AI logic + library
  Game/                    # store + persistence + constants + actions + reducer
  Items/                   # inventory reducers + item types
  Skills/                  # skill engine + library + resource economy (Spec 04 / 04b)
  World/                   # world state, reducers, map and quest libraries
  NPCs/                    # NPC types
  Utils/                   # math, dice, stat derivation, type guards
  CLI/                     # interactive CLIs (not exported by the package)
docs/                      # design notes per system
docs/effects/              # one markdown per buff/debuff
docs/references/           # source material (fallacies, paradoxes, pantheon, Mörk Borg)
specs/                     # implementation specs (numbered 01–24, with story/world/character subdirs from Phase 22)
content/                   # author's notebook: characters / locations / story (not loaded by engine)
plan/                      # build plan, phase briefs, AUDIT.md, CRITIQUE.md, PHASE_CANDIDATES.md
automation/                # standalone walkthrough script + replay fixtures

Documentation

• plan/steps/01_build_plan.md — phased development plan with progress tracking
• docs/source-of-truth-hierarchy.md — Nexus hierarchy for resolving T decisions, CDRs/ADRs, central ledger, build plans, candidates, critique/audit, and reports
• plan/AUDIT.md — code audit and quality findings (drained by /iterate)
• plan/CRITIQUE.md — architecture / quality findings filed by /critique
• Knowledge-Gaps.md — open design and intent questions
• braindump/BRAINDUMP.md — unorganised idea backlog
• docs/testing.md — hermetic e2e testing standard (required for every implementation)
• docs/playtest.md — automated playtest module and Phase 107 fix/playthrough difficulty-tuning loop
• docs/hazard-minigame.md — accepted v0 doctrine for the Mage Knight-like Hazard minigame: route choice, 4 dice, 5-card hand, card/enchantment lifecycle, O - X scoring, 30 action cards (Common/Uncommon/Rare), and 15 hazard cards
• docs/hazard-minigame-api.md — Hazard minigame package-consumer guide: public exports, legal state-machine sequence, mobile presenter boundary, and v0 caveats
• docs/hazard-minigame-prd.md — Hazard minigame PRD: user stories, functional requirements, and success metrics
• docs/hazard-minigame-tdd.md — Hazard minigame TDD: module layout, types, state machine, engine functions, and integration points
• docs/hazard-minigame-bdd.md — Hazard minigame BDD: Gherkin scenarios mapping directly to hermetic e2e test cases
• automation/playtest/BALANCE_LEDGER.md — Phase 107 marker ledger and final sound-mechanics summary stats
• specs/ — implementation specs (00-how-to-use-specs.md is the template; story/ / world/ / characters/ hold the Phase 22 narrative specs)
• docs/ — per-system references (combat, effects, character, world, etc.)
• docs/api.md — Public API reference (stability levels + RN integration recipe)
• docs/effects/ — per-effect deep-dives (one file per buff/debuff; see docs/effects/README.md first)
• docs/references/ — source material (fallacies, paradoxes, pantheon, story)

Scripts

| Script | What it does | | ----------------------- | ----------------------------------------------------------------------------------------------------- | | npm run build | Type-check and compile to dist/ | | npm run type-check | Type-check only | | npm test | Run the vitest suite | | npm run test:watch | Vitest in watch mode | | npm run lint | Run ESLint | | npm run check | Lint + type-check | | npm run verify | Hard gate — type-check && lint && test && build chained; runs before every commit | | npm run deploy:check | Hard gate — npm pack --dry-run + public-surface drift check (Phase 53); runs after every push | | npm run verify:agent | Agent-friendly verify report (Phase 39 + 40); writes automation/last-verify-report.json + markdown summary on stdout | | npm run game | Interactive demo CLI (tabbed loop) |