Ori-Mnemos logo
Ori-Mnemos
★ 333
vs
letta logo
letta
★ 25.2k

Ori-Mnemos vs letta

Ori-Mnemos: Ori Mnemos is an open-source persistent memory infrastructure for AI agents that implements human cognition models on a knowledge graph. It uses ACT-R decay, spreading activation, and Hebbian learning to manage memory, and achieves state-of-the-art retrieval performance while being zero-infrastructure and portable.; letta: Letta is a powerful platform for building stateful AI agents equipped with advanced memory, enabling them to learn and self-improve over time. It provides both a command-line interface for local agent execution and a comprehensive API with Python and TypeScript SDKs for seamless integration into applications.

01

TL;DR

Ori-Mnemos logo
Ori-MnemosMemory & Context · ★ 333

Multi-hop retrieval QA (e.g., HotpotQA)

letta logo
lettaMemory & Context · ★ 25.2k
When to choose:
  • You want a long-lived agent that remembers past work and rewrites its own memory and context over time.
  • You want one agent reachable from CLI, desktop, browser, mobile and messaging apps, with subagents, schedules and hooks.
  • You want memory you can inspect: the README says context is tracked in git and can sync to your own repository.
When to skip:
  • You only need to add memory to an agent you already use through MCP; a small MCP memory server is a lighter fit.
  • You rely on older Letta tutorials or the V1 API server: the project restructured, and the V1 server is retired.
  • You want everything to work without signing in: Letta Cloud is the default backend and some features need it.
02

Side-by-Side Comparison

Field
Ori-Mnemos logoOri-Mnemos
letta logoletta
Category
Memory & Context
Memory & Context
Stars
★ 333
★ 25.2k
License
Apache-2.0
Apache-2.0
Install Command
npm install -g ori-memory && ori init my-agent && cd my-agent
npm install -g @letta-ai/letta-code
Updated
3w ago
5d ago
Open Source
Yes
Yes
Tags
agent-memory, ai-agent, ai-agents
Stateful AI, Agent Platform, Advanced Memory
03

Features

Ori-Mnemos logoOri-Mnemos
01Persistent memory across sessions, clients, and machines
02Knowledge graph with wiki-links, PageRank, and community detection
03Three memory spaces with cognitive forgetting (ACT-R decay)
04Four-signal fusion retrieval (semantic, BM25, PageRank, warmth)
05Retrieval intelligence with Q-learning and meta-learning
letta logoletta
01Build stateful AI agents with advanced memory
02Agents capable of learning and self-improvement over time
03CLI tool for running agents locally in your terminal
04Comprehensive API for integrating agents into applications
05Support for skills and subagents; fully model-agnostic
04

Use Cases

Ori-Mnemos logoOri-Mnemos
↳Multi-hop retrieval QA (e.g., HotpotQA)
↳Long-term conversational memory (e.g., LoCoMo)
↳Persistent AI agent identity and knowledge
letta logoletta
↳Running AI agents locally in your terminal for coding and general tasks.
↳Integrating stateful AI agents into custom applications using the API and SDKs.
↳Developing self-improving AI systems that adapt and learn continually.
05

Best For

Ori-Mnemos logoOri-Mnemos
—
letta logoletta
Most PopularEssentialTrending
FAQ

FAQ

What is the difference between Ori-Mnemos and letta?
Both Ori-Mnemos and letta are in the Memory & Context category. Ori-Mnemos has 333 stars, while letta has 25.2k stars.
Which is better, Ori-Mnemos or letta?
The best choice depends on your use case. Choose Ori-Mnemos if Multi-hop retrieval QA (e.g., HotpotQA), and letta if Running AI agents locally in your terminal for coding and general tasks..
Is Ori-Mnemos free or open source?
Yes, Ori-Mnemos is open source on GitHub (Apache-2.0).
Is letta free or open source?
Yes, letta is open source on GitHub (Apache-2.0).
Cloud Infrastructure
Ad

Deploy on DigitalOcean

Host your MCP servers, Docker containers, and AI agents with $200 free credit over 60 days.

Claim $200 Free Credit
→

Related