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r3

Official registry Data and databases

Local Redis memory MCP for AI apps with hybrid caching and optional Mem0 cloud backup.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package @n3wth/r3
Claude Code 
claude mcp add r3 -e 'MEM0_API_KEY=<your mem0_api_key>' -e 'REDIS_URL=<REDIS_URL>' -- npx -y @n3wth/r3@1.3.2
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "r3": {
            "command": "npx",
            "args": [
                "-y",
                "@n3wth/r3@1.3.2"
            ],
            "env": {
                "MEM0_API_KEY": "<your mem0_api_key>",
                "REDIS_URL": "<REDIS_URL>"
            }
        }
    }
}

Environment variables

  • MEM0_API_KEY secret Optional Mem0 API key for cloud backup (get free at mem0.ai).
  • REDIS_URL Redis connection URL. Uses embedded Redis if unset.

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. r3
  2. Quick start
  3. How it works
  4. MCP client configuration
  5. Tools
  6. Configuration
  7. Comparison
  8. Known issues
  9. Documentation
  10. License

r3

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.

Quick start

npx @n3wth/r3

That single command starts an MCP server backed by an embedded Redis instance and a local vector index. There is no separate database to install and no signup step.

How it works

MCP client (Claude Desktop / Claude Code / Cursor)
        |
        v
   r3 MCP server (stdio)
        |
   +----+-----------------------+
   |                            |
embedded Redis            vectra local index
(redis-memory-server,      (on-disk vector store
 auto-downloaded binary,    for semantic search,
 no external service)       no external service)
   |
   +--- optional ---> Mem0 cloud API (MEM0_API_KEY)
                       cross-device sync, off by default
  • Embedded Redis — redis-memory-server downloads and manages a local Redis binary for you. It stores memory content and metadata. If it cannot start, r3 falls back to an in-process store.
  • vectra — a local, file-backed vector index used for semantic search. No network calls, no external vector database.
  • Mem0 (optional) — if MEM0_API_KEY is set, r3 also syncs to Mem0's cloud API so memories can follow you across machines. Without a key, nothing leaves your machine.

MCP client configuration

Claude Desktop

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "r3": {
      "command": "npx",
      "args": ["@n3wth/r3"]
    }
  }
}
Claude Code
claude mcp add r3 "npx @n3wth/r3"
Cursor

Add to .cursor/mcp.json in your project (or the global Cursor MCP config):

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

Restart the client after editing config. In a new conversation:

You: Remember that I prefer TypeScript and dark mode.
AI: I'll remember that.

[new conversation]

You: What are my preferences?
AI: You prefer TypeScript and dark mode.

Tools

ToolDescription
add_memoryStore content with optional metadata and priority
search_memoryQuery memories using semantic or keyword search
get_all_memoriesList stored memories with pagination
get_memoryRetrieve a specific memory by ID
update_memoryModify existing memory content or metadata
delete_memoryRemove a memory
deduplicate_memoriesFind and merge duplicate memories
cache_statsReport cache hit rate and storage stats
sync_statusReport Mem0 cloud sync status
optimize_cacheRun cache maintenance
import_memoriesBulk import memories

Enhanced mode (default, INTELLIGENCE_MODE=enhanced) adds:

ToolDescription
extract_entitiesExtract named entities from text
get_knowledge_graphReturn the entity/relationship graph
find_connectionsFind entities connected to a given entity

Configuration

Environment variables, all optional:

VariableDescriptionDefault
REDIS_URLUse an external Redis instead of the embedded oneembedded server
MEM0_API_KEYEnables Mem0 cloud syncunset (local only)
MEM0_USER_IDNamespace for memoriesdefault
INTELLIGENCE_MODEenhanced or basicenhanced

Example with cloud sync enabled:

{
  "mcpServers": {
    "r3": {
      "command": "npx",
      "args": ["@n3wth/r3"],
      "env": {
        "MEM0_API_KEY": "mem0_..."
      }
    }
  }
}

Comparison

r3mem0 (OSS)zep
Runs fully local with zero configyes (embedded Redis + vectra)requires a Postgres/vector DB you configurerequires a Postgres instance you configure
Needs an API key to try itnono (self-hosted) / yes (cloud)yes (cloud), or self-hosted setup
Optional cloud syncyes, via Mem0n/a (is the cloud option)yes

This table only reflects setup requirements observed in each project's own documentation, not benchmark performance or feature completeness. Verify against current upstream docs before relying on it.

Known issues

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

Documentation

Full documentation at r3.n3wth.com.

License

MIT

Frequently asked questions

What is r3?

Local Redis memory MCP for AI apps with hybrid caching and optional Mem0 cloud backup.

How do I install r3?

It runs on your machine. In Claude Code: claude mcp add r3 -e 'MEM0_API_KEY=<your mem0_api_key>' -e 'REDIS_URL=<REDIS_URL>' -- npx -y @n3wth/r3@1.3.2. For other clients, paste the JSON configuration from this page into their MCP settings.

Does r3 need an API key?

Yes. It expects MEM0_API_KEY, which you set in its configuration.

Is r3 open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains r3?

It is published by n3wth. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.