SUBSTRATE
Attach a persistent entity layer—with causal memory, emotional state, and identity—to your agent via SUBSTRATE MCP for long-running character or companion experiments.
Overview
SUBSTRATE is a MCP server for the Build phase that gives AI agents a persistent entity layer with causal memory, emotional state, and identity.
What is this MCP server?
- Persistent AI entity framework: causal memory, emotional state, and identity
- npm substrate-mcp 1.0.1 with stdio transport
- Remote streamable-http endpoint at substrate.garmolabs.com for hosted MCP access
- Designed for continuity across sessions rather than stateless tool calls
- Open-source substrate-mcp repository on GitHub for extension and self-host paths
- Server version 1.0.1
- npm identifier substrate-mcp with stdio transport
- Hosted remote: https://substrate.garmolabs.com/mcp-server/mcp (streamable-http)
What problem does it solve?
Stateless agents forget context and motive, so multi-session companions and narrative products feel brittle and repetitive.
Who is it for?
Solo builders experimenting with long-lived agent personas, games, or tools that need session-spanning memory.
Skip if: Simple one-shot codegen tasks or teams that want plain RAG without identity or affect modeling.
What do I get? / Deliverables
Your agent stack can read and update a structured persistent entity with memory, emotion, and identity over time.
- SUBSTRATE MCP connected via stdio or remote URL
- Agent tools operating on persistent entity state
- Foundation for multi-session identity and causal memory in your agent product
Recommended MCP Servers
Journey fit
Persistent agent personality and memory systems are built when you shape how your AI product behaves over sessions. SUBSTRATE is agent infrastructure and memory semantics, not frontend UI or launch distribution—canonical shelf is build → agent-tooling.
How it compares
Persistent entity/memory MCP framework, not a generic chat memory plugin or vector DB alone.
Common Questions / FAQ
Who is SUBSTRATE for?
Developers building agent-backed experiences that need durable identity and causal memory across sessions.
When should I use SUBSTRATE?
During build when you are designing agent-tooling for companions, RPG NPCs, or products with evolving emotional state.
How do I add SUBSTRATE to my agent?
Install npm substrate-mcp for stdio or point your MCP client at the streamable-http remote https://substrate.garmolabs.com/mcp-server/mcp per your host’s docs.