Quest System

Quest System

Build the quest layer of a game — data model, runtime, the scripting engineering, emergent options, tracking UX, and authoring. Dialogue is a consumer interface (dialogue-system). References: BotW/TotK (the datamined flag-driven school) and Genshin (the datamined condition/exec school), with Witcher 3's REDkit and Skyrim's Creation Kit as authoring references, and Shadow of Mordor/Outer Wilds/Elden Ring for emergent and tracking models.

The architecture rule

Quests are data that observe the world — the world never waits for the quest. Definitions are immutable data; runtime state lives separately, keyed by stable IDs; progression is event-driven. A quest is a small program — a tiny state machine whose transitions are gated by gameplay conditions and whose state-entry runs side-effecting actions.

DATA MODEL  taxonomy (types differ by policy) | Chapter→Quest→Step hierarchy |
            a DAG of prerequisites | per-step conditions + actions + world
            bindings + text KEYS (never text)
RUNTIME     gameplay emits typed events; objectives subscribe; NO per-frame
            polling (dirty-queue); world writes through the step's action list
            into the shared world-state store; Inactive→Active→Completed
            (+ Failed + Suspended from day one)
AUTHORING   graph (Witcher 3) | numbered stages (Skyrim) | condition/exec tables
            (Genshin, BotW); invariants: text separated from logic, debug console
            built WITH the runtime, additive-only patching

Reference map

| File | Covers | | --- | --- | | [data-model.md](./data-model.md) | The two shipped schools (BotW flags, Genshin condition/exec), taxonomy as policy data, the prerequisite DAG, conditions/actions and combinators, hidden quests and world permanence | | [runtime.md](./runtime.md) | Event-driven evaluation, the shared-NPC conflict and arbitration, declarative world integration, no-fail/no-abandon design, daily commissions, co-op authority | | [emergent.md](./emergent.md) | Radiant/template quests (the alias system), the Nemesis system, storyteller vs AI-director pacing, simulation-driven emergence (Dwarf Fortress/Qud/A-Life), ambient encounters, the authored-backbone hybrid and its real maintenance cost | | [scripting.md](./scripting.md) | The engineering: state machine vs behavior tree (UE5 StateTree), the event bus / GameplayMessageSubsystem, dependency graphs and topological sorting, condition/action systems and polymorphic serialization, save/load and schema migration, debug tooling and telemetry | | [tracking.md](./tracking.md) | Quest-log/journal structures, objective markers and waypoints, the anti-marker philosophy (Elden Ring/BotW/Ghost of Tsushima), map integration, tracking interaction at scale, special models (Outer Wilds ship log, Obra Dinn deduction, Disco Elysium thought cabinet) | | [pitfalls.md](./pitfalls.md) | 16 failure modes (symptom → cause → prevention) with real incidents (USSEP catalog, New World, "another settlement needs your help"), debugging order, ship checklist |

What the datamines prove

• BotW: a quest is a flag-driven step list — each step advances when its

NextFlag turns true; steps declare NPC schedule overrides and map indicator positions. The quest is an observer; event scripts and AI set the flags. This is why any-order play works: state drives quests, never sequence.

• Genshin: Chapter → MainQuest → SubQuest with typed categories, a

prerequisite DAG, and pure-data per-subquest acceptCond/finishCond/failCond + beginExec/finishExec/failExec — all logic by composing typed conditions and actions, no per-quest code. Plus isRewind: a safe-resume checkpoint.

• No-fail is a design choice both games made: BotW's schema has no fail field;

Genshin exposes failure only in Hangout branches and perishable commissions. Decide your fail policy globally, day one.

Build order (4 shippable tiers)

Tier 1 — Model and runtime core
- [ ] Quest/step definitions as data + runtime state by stable ID
- [ ] Typed world events + objective subscription; the dirty-queue evaluator
- [ ] The step lifecycle with transactional advance
- [ ] DEBUG CONSOLE DAY ONE: set-stage, skip, complete, dump state
Tier 2 — World integration
- [ ] World-state store shared with save-persistence
- [ ] Step world bindings (NPC overrides, spawns, area unlocks, weather)
- [ ] Step-entry precondition revalidation ("already true?" → auto-complete)
- [ ] The shared-NPC arbiter: lock + UI explanation + suspension escape
Tier 3 — Taxonomy and tracking
- [ ] Quest types as policy data; hidden quests via the trigger registry
- [ ] Daily commissions: regional pools, cycles, 4 AM reset
- [ ] Tracking contracts: markers DERIVED from objective state; the log;
      navigation handoff; pick a marker philosophy (full / area / anti-marker)
- [ ] Reward grants idempotent, keyed by quest+step ID
Tier 4 — Branching, emergent, live-service
- [ ] Branching quests with checkpoints
- [ ] Emergent layer if used (radiant templates / director) over an authored backbone
- [ ] Quest state versioning + migrations; additive-only patching
- [ ] Co-op authority model decided explicitly

Key numbers (starting points — sourced anchors)

| Parameter | Value | Anchor | | --- | --- | --- | | Content scale | BotW 133 quests (+19 DLC); TotK 253; Genshin 608 world quests + ~40 Archon acts | wiki | | Step granularity | Skyrim stages 0–65535, convention increments of 10, 200 = done | official docs | | Commissions | 4/day from regional pools, reset 04:00 server | wiki | | Skyrim debug | setstage one stage at a time (jumping stages skips side-effects) | UESP | | StateTree | UE5 HSM: evaluate only current-state transitions (cheap vs BT retick) | Epic docs | | Radiant | template + aliases filled by conditions + Story Manager events | CK docs | | Ghost of Tsushima | "Weenies" landmark taxonomy: something calls the player every ≤30 s | GDC | | Tracking | 1 navigated quest at a time; unlimited active (both reference games) | wiki |

Full sourced tables (with flagged "do-not-invent" gaps) in each reference file.

Engine mapping (summary)

| Generic block | Unity 6 | UE5 (5.4+) | | --- | --- | --- | | Definitions | ScriptableObject per quest (immutable) + POCO runtime state by string ID | PrimaryDataAsset / DataTable rows | | Flow control | SO quest graph / FSM; [SerializeReference] state lists | StateTree (HSM): States + Tasks + Evaluators, per-state bindings | | Event bus | GameEvents singleton + typed bus; dirty-queue | GameplayMessageSubsystem (tag channels, local) + GAS GameplayEvent (networked) | | Conditions/actions | polymorphic [SerializeReference] with AND/OR/Min-N combinators | typed structs + GameplayTags as the fact store (hierarchical subscription) | | Live-service content | Addressables for quest prefabs/scenes | GameFeature plugins (Epic's additive-content pattern) | | Ecosystem | Quest Machine (Pixel Crushers) | Narrative Pro |

Full detail in [scripting.md](./scripting.md).

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Firzus
• Source: Firzus/agent-skills
• License: MIT

Install and usage instructions live in the source repository linked above.