R3 MCP Server

Persistent memory for MCP clients (Claude Desktop, Claude Code, Cursor) that runs entirely on your machine, with no accounts, no API keys, and no cloud service required to start. Its 14 documented tools cover memory, memories, cache. It runs locally over stdio via the published package.

People who work with memory, memories and cache and want it reachable from Claude, Cursor, VS Code, or another MCP client. The project is written in TypeScript.

VERIFIED ACTIVE

LAST COMMIT 2026-09-09 · ★ 2 · #169 OF 304 MAINTAINED MEMORY · VERIFIED 2026-09-18

MIT · TypeScript servers · how we verify → /methodology

01 · Install R3

before you install - you'll need

MEM0_API_KEY is optional or environment-specific per the README.

Claude Code

claude mcp add n3wth-r3 -- npx -y @n3wth/r3

Claude Desktop / Cursor / VS Code - add to config

{
  "mcpServers": {
    "n3wth-r3": {
      "command": "npx",
      "args": [
        "-y",
        "@n3wth/r3"
      ]
    }
  }
}

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions

license MIT - declared in the repository

npm package @n3wth/r3 - published under the repo owner's npm scope (@n3wth)

registry namespace io.github.n3wth is GitHub-verified and matches the repo owner

03 · What R3 can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

What you can build

With this server connected, an agent can query memories using semantic or keyword search, list stored memories with pagination, retrieve a specific memory by ID, and remove a memory.

Capability map

Tools grouped from the project's README - what R3 lets an agent do.

read & search

5 tools - e.g. Query memories using semantic or keyword search; List stored memories with pagination; Retrieve a specific memory by ID

search_memory · get_all_memories · get_memory · get_knowledge_graph · find_connections

create & write

1 tool - e.g. Store content with optional metadata and priority

add_memory

update

1 tool - e.g. Modify existing memory content or metadata

update_memory

delete

1 tool - e.g. Remove a memory

delete_memory

Deduplicate

1 tool - e.g. Find and merge duplicate memories

deduplicate_memories

Cache

1 tool - e.g. Report cache hit rate and storage stats

cache_stats

Sync

1 tool - e.g. Report Mem0 cloud sync status

sync_status

Optimize

1 tool - e.g. Run cache maintenance

optimize_cache

Limitations (from the README)

See LAUNCH_AUDIT.md for current limitations, including a native module build failure on some macOS setups.

Latest releases

v1.3.2 · 2026-09-01

R3 v1.3.2 · Intelligent memory layer for AI applications with sub-5ms response times. · Installation · bash · npm install @n3wth/r3@1.3.2 · Claude Desktop Setup · bash · npx @n3wth/r3 · Getting Started · API Reference…

v1.3.1 · 2025-09-16

Added OpenGraph image support for better social media sharing · Fixed OpenGraph image reference to use correct PNG file · Updated image dimensions to match actual file (1280x720) · Added absolute URL for proper social…

v1.2.11 · 2025-09-14

R3call v1.2.11 · Lightning-fast memory layer for AI applications with sub-5ms response times. · Installation · bash · npm install r3call@1.2.11 · Claude Desktop Setup · bash · npx r3call · Getting Started · API…

04 · Who maintains R3

r3 is maintained by n3wth. We track 2 MCP servers from n3wth - 2 actively maintained, 2 combined GitHub stars, oldest repo from Sep 2025.

05 · Facts

repository: github.com/n3wth/r3
website: https://r3.n3wth.com/
category: memory - ranked #169 of 304 actively-maintained memory servers as of 2026-09-18.
release cadence: 1 release in the last 90 days (latest 2026-09-01)
registry: io.github.n3wth/r3 (active, first published 2026-09-09)
packages: npm:@n3wth/r3

06 · R3 FAQ

Is R3 still maintained?

Yes - as of 2026-09-18, its last commit was 2026-09-09 and it shipped 1 release in the last 90 days. We re-verify nightly.

What can R3 do?

With this server connected, an agent can query memories using semantic or keyword search, list stored memories with pagination, retrieve a specific memory by ID, and remove a memory.

How do I install R3?

Run `npx -y @n3wth/r3`. The README documents one environment variable (MEM0_API_KEY) to set first. MEM0_API_KEY is optional or environment-specific per the README. You can also paste the ready-made client config above.

Does R3 run locally?

Yes - it's a stdio server: it runs on your machine (via npx) with your user's permissions. Your data stays local unless the server itself calls external APIs.

07 · Alternatives to R3

Alternatives to R3

Maintained memory servers if R3 isn't the fit.

Pairs well with

Servers that cover what R3 doesn't - only shown when the pairing reason fits the companion.

More memory MCP servers · Nan Forget · MemHeaven - Self-hosted Remote MCP Memory for ChatGPT · Graphlens MCP · Context Pod

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