Yes. The MCP server is MIT-licensed and free. Letta itself is open source under Apache-2.0 and can be self-hosted, and Letta also sells a hosted service; the MCP server needs one of them to talk to.

Does it support remote or OAuth?

It can serve Streamable HTTP when you set TRANSPORT=http, but you host it yourself; there is no public endpoint. Auth is a Letta password or API token in an environment variable, not OAuth.

Is it official, and how does it compare to Glen?

It is a community project by Oculair Media, not published by Letta. It manages memory that lives inside Letta agents. Glen records the sessions of the coding agents a team already uses and makes them searchable across the org, without moving work into a separate agent platform.

Letta MCP server

CommunityOculair Media (community)80Config last verified Nov 10, 2026

Community MCP server for Letta: manage stateful Letta agents, their memory blocks, archival passages, tools, and sources from any MCP client.

Letta, the platform formerly known as MemGPT, runs stateful agents whose memory has two tiers: core memory blocks that sit in the agent's context window, and archival memory, passages stored outside the context and retrieved by search. This MCP server, a Rust binary maintained by Oculair Media rather than by Letta, talks to the REST API of a Letta server you name with LETTA_BASE_URL. It lets another agent, such as Claude Code or Cursor, create and message Letta agents, read and edit their core memory blocks, attach shared blocks to several agents, and add, search, or delete archival passages.

The server packs 103 operations into seven tools, each taking an operation argument: agents, memory, tools, sources, jobs, file sessions, and MCP server registrations. It runs over stdio by default or Streamable HTTP with TRANSPORT=http, is published to npm as letta-mcp-server with prebuilt binaries for macOS, Linux, and Windows, and is MIT-licensed. Memory scope follows Letta's model: blocks and passages belong to agents on that Letta server, so the calling agent works with whatever the Letta deployment holds and has to decide when to read or write it.

Quick install

Copy-paste configs are provided for all 8 supported clients. Pick your client below.

Add to ~/.claude.json

~/.claude.json

json

{
  "mcpServers": {
    "letta": {
      "command": "npx",
      "args": [
        "-y",
        "-p",
        "letta-mcp-server",
        "letta-mcp"
      ],
      "env": {
        "LETTA_BASE_URL": "<LETTA_BASE_URL>",
        "LETTA_PASSWORD": "<LETTA_PASSWORD>"
      }
    }
  }
}

Or via CLI

bash

claude mcp add letta -- npx -y -p letta-mcp-server letta-mcp

Step-by-step guides

Available tools

Tool	Description
letta_agent_advanced	Agent lifecycle and messaging: list, create, update, delete, clone, export and import agents; send, stream, or cancel messages; manage conversations, context, and summaries.
letta_memory_unified	Memory operations: read and update core memory, create and attach blocks, create, search, update, and delete archival passages, and manage archives.
letta_tool_manager	Tool CRUD and upsert, attach, detach, or bulk attach tools to agents, generate a tool or schema from a prompt or source, and run tool source.
letta_source_manager	Data sources: create, update, delete, attach to agents, upload and delete files, and list folders and their contents.
letta_job_monitor	List jobs, list active jobs, get one job, or cancel it.
letta_file_folder_ops	Open and close an agent's file sessions, and attach or detach folders.
letta_mcp_ops	Register MCP servers with Letta: add, update, test, connect, resync, list their tools, register or execute a tool, and attach a server's tools to an agent.

Required configuration

LETTA_BASE_URLRequired
URL of the Letta server's API, for example http://localhost:8283.
LETTA_PASSWORDRequired
Letta server password. LETTA_API_TOKEN is accepted instead when LETTA_PASSWORD is unset.
TRANSPORTOptional
stdio (default) or http.
PORTOptional
HTTP port when TRANSPORT=http. Defaults to 6507.
LETTA_MCP_MAX_VALUE_LENOptional
Maximum characters returned for block, passage, and search values. Defaults to 500.
LETTA_MCP_CORE_MEMORY_PREVIEW_LENOptional
Maximum characters in core memory previews. Defaults to 200.

What you can do with it

Inspect and correct a Letta agent's memory

From Claude Code, read an agent's core memory blocks with letta_memory_unified, fix a wrong fact with update_core_memory, and check the result without opening the Letta dashboard.

Share a memory block across agents

Create one block, for example a project brief, and attach it to several Letta agents so an edit to it reaches all of them on their next turn.

Delegate a task to a long-running agent

An MCP client sends a message to a Letta agent that keeps its own archival memory between runs, and reads the reply back through letta_agent_advanced.

FAQ

Is it free?: Yes. The MCP server is MIT-licensed and free. Letta itself is open source under Apache-2.0 and can be self-hosted, and Letta also sells a hosted service; the MCP server needs one of them to talk to.
Does it support remote or OAuth?: It can serve Streamable HTTP when you set TRANSPORT=http, but you host it yourself; there is no public endpoint. Auth is a Letta password or API token in an environment variable, not OAuth.
Is it official, and how does it compare to Glen?: It is a community project by Oculair Media, not published by Letta. It manages memory that lives inside Letta agents. Glen records the sessions of the coding agents a team already uses and makes them searchable across the org, without moving work into a separate agent platform.

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