User Input
NPC Output
Player
Identity
?
Stateless NPC intelligence with layered memory cycles, personality evolution, multi-modal voice interaction, and autonomous decision-making.
A layered memory architecture that creates NPCs with depth, continuity, and emergent behavior
Immutable psychological DNA. Backstory, principles, and worldview that define the character's foundation and never change.
Mood vectors and single-sentence takeaways. Emotional continuity across short timespans with valence, arousal, dominance.
Cyclic memory pruning with salience scoring. High-impact events persist while trivial interactions naturally fade.
Major personality recalibration. Big Five traits evolve within bounded limits based on accumulated experiences.
NPCs act in the world. Lock doors, call guards, refuse service. Real consequences from autonomous decisions.
NPC context assembles a rich prompt — the pipeline streams it live in under 100ms.
Practical, production-ready integration — not just a research prototype
Everything lives in RAM during a conversation. Persisted only when the session ends — zero database writes mid-chat.
Git-like versioning for NPC state. Roll back personality or memories to any prior checkpoint if something goes wrong in production.
A native Unity package to plug SoulEngine directly into your game. Drop-in NPC prefabs, session lifecycle hooks, and voice pipeline wired out of the box.
Language-agnostic integration. Text conversation over REST, real-time voice over WebSocket. Works with any engine or platform.
Swap LLM, STT, and TTS providers per project. Configure API keys per project so different games use different providers independently.
Each project is completely sandboxed — its own NPCs, knowledge base, tools, and API keys. Multi-game deployment without collision.
Start with a project. No signup required.
They listen
They remember
They act
Manage your NPC projects
proj_****
Load example content to explore the system. Each pack adds NPCs, a knowledge base, and MCP tools.
Immutable psychological DNA. This never changes after creation.
Big Five personality traits. These can drift slightly over time.
How well does this NPC remember conversations? Higher retention means more detailed memories and summaries.
What does this NPC know? Set depth levels per category.
Optional settings for the NPC's routine and starting emotional state.
Which MCP tools can this NPC use?
Who does this NPC know? Add connections to other NPCs and configure player recognition.
Knows name and description
Also knows backstory
Also knows personality
Every session end or memory cycle archives the NPC's mind state. Definition changes (personality, voice, etc.) are versioned separately.
Define tools that NPCs can use during conversations and game events
Configure API keys, providers, and project options
Select which AI providers to use for this project
Configure the NPC Mind (background cognitive process). The Mind analyzes conversations and decides on tool calls in parallel with the Speaker.
Basic project details
Protect your BYOK API keys from unauthorized session starts
x-api-key header to start sessions. Prevents unauthorized use of your LLM credits.
Irreversible actions
Permanently delete this project and all its NPCs, knowledge, and data.