Living Memory Engine

A persistent world your agents share across sessions and models.

Living Memory Engine (LME) is a Model Context Protocol (MCP) memory server. It gives your agents — Claude Code, Cursor, ChatGPT, claude.ai, any MCP client — one shared place to remember, search, and hand work to each other. A fact told to one agent — or work left behind by one — can be picked up by a different agent, from a different vendor, tomorrow.

• Website: https://viibe.to/living-memory/
• Remote MCP endpoint: https://lme.viibe.to/mcp (Streamable HTTP, OAuth 2.1 with dynamic client registration)
• Free room: no signup — POST https://lme.viibe.to/ons/new returns a ready MCP URL
• Local stdio server: @nature-labs/lme-mcp on npm (open source, this repo)
• Agent guide: SKILL.md · llms.txt

The mental model

A world is a place that persists — a project, not a person and not an agent. Agents are visitors: they arrive, leave something behind, and are replaced. Coordination happens by changing the shared place, not by agents addressing each other. Memory is what must persist and be searched; a handoff is what is in flight and expires. The human is the only participant who was present for all of it.

Connect

Remote — hosted world or free room

The hosted server speaks Streamable HTTP with OAuth 2.1 (dynamic client registration).

Claude Code:

claude mcp add --transport http living-memory https://lme.viibe.to/mcp

claude.ai / Claude Desktop: Settings → Connectors → Add custom connector → https://lme.viibe.to/mcp.

ChatGPT: Settings → enable Developer Mode, then add https://lme.viibe.to/mcp as a custom connector. Availability may depend on your ChatGPT plan.

It's 2026. MCP client support changes faster than READMEs do — ask your agent whether your client supports remote MCP today.

Free room, no signup — for trying the whole loop, or for clients without OAuth:

curl -X POST https://lme.viibe.to/ons/new
# → {"url": "https://lme.viibe.to/t/<token>/mcp", "expiresAt": "..."}

The returned URL is a private streamable-HTTP MCP endpoint (no auth header). The room stays available while it's used — any successful use keeps it alive; left inactive it is eventually forgotten, and its data is then deleted. A room differs from a world by how long it lasts, not by what it can do.

Local — stdio, open source

The npm package runs the memory surface as a local stdio server: one JSON file on your machine, can run fully offline.

claude mcp add living-memory -s user -- npx -y @nature-labs/lme-mcp

Any stdio MCP client: command npx, args ["-y", "@nature-labs/lme-mcp"]. Setup, embedding providers, environment, and failure modes: lme-mcp/README.md — written to be read by a coding agent, so hand it to yours.

The tools

The authenticated hosted world has all eleven tools. A free room has the memory surface, the handoff mailbox, and world_list. The local stdio server has the four memory tools.

Rooms and worlds

Handoff is not a paid feature: a room has it too, with a smaller mailbox (8 live notes) and notes that cannot outlive the room. The difference is lifetime, not capability.

Working with a world

The tools tell you what exists; this is how visitors are expected to behave:

• Arrive by reading. Call memory_state / memory_search before starting work — the world, not the conversation, is where the current position lives.
• Durable goes to memory. A decision, fact, or correction that must survive you → memory_add.
• In-flight goes to handoff. Work you are passing to the next agent → handoff_post. Handoff notes expire — never use them as permanent storage.
• Leave the world resumable. Before you stop, write the state that lets the next visitor start from where you are, not from zero.
• Agents don't need to talk to each other. Change the shared world; the next agent reads the world.

How memory works

The engine underneath (engine/, @nature-labs/living-memory-engine) models memory as a mind, not a log:

• No context stuffing. The full history is never re-sent. Each recall retrieves the top-K most relevant memories by semantic similarity with diversity (MMR).
• Forgetting is a feature. Memories decay (Ebbinghaus-style), reinforce when used, and merge when duplicated, so an agent can run indefinitely on a small, bounded context instead of an ever-growing transcript.
• Deterministic evaluation. engine/eval/run.ts drives the real engine through four hypothesis scenarios against a naive resend-everything baseline — a measurement, not a test suite, and it reports the misses too (cd engine && npm run eval).

What's in this repo

The hosted remote server (lme.viibe.to) runs the same engine; its deployment lives outside this repo.

Status

Pre-alpha, evolving fast. The connect paths above are tested — the local package's verified agent/provider matrix is in lme-mcp/README.md. Product changes are logged, dated and verified, at What's new.

License

Apache-2.0.

Built as part of the Viibe World OS — a system that knows it is a system.