A transparent memory vault connects three information islands and brings knowledge cards together.
AI-generated conceptual illustration.

TL;DR

  • Long-running agents face lost context, weak retrieval, growing token costs and fragmented information across sessions.
  • The original review highlights Mem0, Letta, Cognee and SuperMemory, alongside eight related projects.
  • Its selection framework starts with the use case: a prototype, a stateful production agent, relationship-heavy reasoning or multi-agent collaboration.

Project descriptions and star counts below are from the original March 26, 2026 article.

1. Four obstacles for long-running agents

Task completion

A model’s context window is limited. As a conversation grows, earlier constraints may be lost or displaced, making long, multi-step tasks harder to complete consistently.

Fragmented memory and weak retrieval

Storing every conversation as a flat list in a vector database does not guarantee that the right detail will be retrieved.

For example, “the parameters of that Python script we used last time” may need to resolve to a record about a named file and its configuration. Similarity between words is only part of that task.

Token costs

One response to lost context is to include more history in every prompt. That increases the amount of material processed and the cost of repeated requests.

The original article uses long GPT-4o contexts as an example of this problem. The general design question is how to supply useful context without repeatedly sending the entire history.

Information split across services

A user may discuss a task in one channel and expect an agent in another channel to continue it. Separate conversation stores make that difficult, especially when the agent also needs CRM data, documents and team messages.

Poor memory can therefore lead to larger prompts, greater cost and a harder deployment process.

2. Twelve approaches

1. Mem0 — approximately 51,334 stars

Positioning in the original review: a general-purpose memory layer for AI agents.

The review highlights extraction, consolidation and retrieval to maintain continuity; compression and prioritization to reduce context size; and a common API for memory across sessions.

It describes recent, important and long-term memory, with retention based on time and relevance, and emphasizes self-hosting.

Suggested use: prototypes, assistants that remember preferences, and customer-service agents that need consistency across conversations.

2. Letta — approximately 21,785 stars

Positioning: a platform for stateful agents.

The review focuses on persistent agent state, memory management, summaries and information sharing between agents. It also describes integration with commonly used agent frameworks.

Suggested use: long-lived assistants, enterprise support and applications that need continuity across sessions.

3. Cognee — approximately 14,717 stars

Positioning: a knowledge engine that turns documents into a network of related information.

The article emphasizes the combination of vector retrieval and knowledge graphs. The aim is to retrieve relationships between entities as well as semantically similar text.

It also describes extracting knowledge from different input formats, returning structured context, and inspecting the resulting graph through a local interface.

Suggested use: relationship-heavy document tasks, research assistants and knowledge bases built from unstructured material.

4. SuperMemory — approximately 20,076 stars

Positioning: a fast, scalable memory API.

The original review emphasizes retrieval latency, compression, hybrid vector and keyword search, and a straightforward integration interface.

Suggested use: interactive agents and applications sensitive to response time.

5. MemVid — approximately 13,642 stars

Positioning: a memory approach based on video-encoded storage.

The article describes encoding stored information into video, with retrieval and replay as alternatives to a more elaborate retrieval pipeline.

Suggested use in the original review: long-term archives and large histories where storage and context costs are a concern.

6. Memori — approximately 12,781 stars

Positioning: a SQL-native memory layer for language models and agents.

The review emphasizes relational queries, a shared SQL store and integration with an existing enterprise stack.

Suggested use: organizations already using SQL and applications requiring structured memory queries.

7. DeepLake — approximately 9,053 stars

Positioning: an AI data runtime and multimodal data layer.

The article describes support for vectors, text, images and video, with indexing designed around AI workloads and options intended to reduce operational work.

Suggested use: multimodal agents and large-scale data retrieval or training.

8. MemOS — approximately 7,910 stars

Positioning: a memory operating system for models and agents.

The review focuses on persistent skills, reuse across tasks and knowledge sharing among agents. It describes compatibility with agent ecosystems such as OpenClaw and MoleBot.

Suggested use: systems in which multiple agents accumulate and reuse skills.

9. OpenViking — approximately 19,650 stars

Positioning: a context database designed for AI agents such as OpenClaw.

The article describes a filesystem-like hierarchy for memory, resources and skills, with context delivered at different levels of detail.

Suggested use: OpenClaw-related systems and applications with complex context-management needs.

10. 12-factor-agents — approximately 18,957 stars

Positioning: principles and practices for production agents.

This is a different kind of resource from a memory-storage engine. The review presents it as guidance for moving from a prototype to production, including memory, safety and monitoring.

Suggested use: teams designing and deploying production systems.

11. PraisonAI — approximately 57,742 stars

Positioning: a low-code platform for multi-agent automation.

The article highlights built-in memory and retrieval support, handoffs and guardrails, support for many models, and integrations with services such as Telegram, Discord and WhatsApp.

Suggested use: business automation and workflows that coordinate several specialized agents.

12. MemMachine — roughly 5,000 stars in the original comparison table

Positioning: a general-purpose memory layer.

The review focuses on a common memory interface, support for different storage backends, and simplifying the state-management work of a larger agent system.

Suggested use: systems that need a consistent abstraction over storage and retrieval.

3. Comparison

The strengths and suitability below summarize the original author’s assessments.

Project Main emphasis Suggested use
Mem0 General-purpose memory and accessible integration Prototypes and memory across sessions
Letta Persistent agent state Long-lived assistants and support
Cognee Graph and vector retrieval Relationship-heavy knowledge tasks
SuperMemory Fast retrieval Interactive, low-latency applications
MemVid Video-based memory storage Archival and long histories
Memori SQL-based memory Existing relational-data stacks
DeepLake Multimodal data Large and varied datasets
MemOS Reusable skills and shared memory Multi-agent collaboration
OpenViking Hierarchical context Complex context management
12-factor-agents Production design principles Architecture and deployment
PraisonAI Low-code multi-agent workflows Business automation
MemMachine A common memory abstraction Complex agent systems

4. Direction and selection

The original article sees agent memory as a rapidly expanding area. It identifies three development directions:

  1. Compression: representing more useful information with less context.
  2. Temporal reasoning: distinguishing an old preference from the current one.
  3. Multimodal memory: incorporating information from images, audio and video.

Its practical starting points are:

  • Prototype: evaluate Mem0 or SuperMemory.
  • Production architecture: investigate Letta alongside the principles in 12-factor-agents.
  • Relationships and context: investigate Cognee or OpenViking.
  • Multiple agents: investigate PraisonAI or MemOS.
  • Archival experiments: investigate MemVid.

These are the original review’s selection suggestions; they are starting points for evaluating a workload, rather than a substitute for testing it.

Originally published on Jayln3’s Blog. Please credit the source when quoting or republishing.