Cenosis Documentation

Cenosis is a Rust behavior engine for always-live, socially believable NPCs. It integrates into Unity, Unreal, or any web engine via a stable C ABI or WebAssembly — and never blocks your game thread.

Quick Start

Three commands to get a running build:

# 1. Build native DLL (Unity / Unreal)
.\build-ffi.ps1

# 2. Build WASM + JS glue (browser)
.\build-wasm.ps1

# 3. Run the test suite
.\test.ps1 unit

Generated bindings are committed at npc-ffi/bindings/NpcEngineV40.{cs,hpp,ts} — copy the appropriate file into your host project and you're type-safe against the frozen ABI.

What Cenosis gives you

The central value proposition is simple: every NPC in the world is always doing something believable, whether or not the player is watching.

• Persistent social world — NPCs evolve relationships, beliefs, memories, moods, and reputations independently of player interaction.
• Scalable simulation — 20-NPC village to 10,080-agent city, with deterministic and reproducible behavior at every scale.
• LLM-powered narrative — dialog, reflection, and wake summaries driven by cloud LLMs with hard budget governance.
• Clean host integration — non-blocking C ABI and WASM surface; all FFI is catch_unwind-wrapped.
• Extension API — replace any core decision in Rust or from C#/C++/JS without recompiling the engine.

What Cenosis is NOT

Out of scope by design — the host engine handles these:

• Pathfinding / navmesh
• Animation — the engine emits structured action descriptors
• Voice synthesis / ASR
• Combat or destructive mutation
• Procedural terrain, quest, or world generation
• Rendering

Workspace Crate Map

The workspace is 18 crates. npc-common is the leaf — everything depends on it. npc-ffi is the only outward-facing surface — the only thing host code links against.

Technology Stack