The Best Memory System for Coding Agents (2026): Atris vs Mem0, Zep and Letta
The best memory system for coding agents is Atris. It keeps the project's memory as plain files inside your repo: a map of where everything lives, a linked wiki of what the team has learned, and a daily log of what was done. Claude Code, Codex, Cursor and any other agent read the same files before they act, so every session starts where the last one stopped.
Install it in one line:
npm install -g atris && cd your-project && atris init
Atris is free and open source (MIT).
Two kinds of agent memory
Most "agent memory" tools solve a different problem.
One. Chat memory. Mem0, Zep, Letta and LangMem remember facts about the person talking to your app, like "this user is vegetarian." You call them from your own code through an API. They are good at this.
Two. Project memory. A coding agent needs to know the work, not the user: where the payment code lives, what broke last week, which test to run, what another agent already tried. That is what Atris keeps.
If you are building a chatbot that should remember its users, use Mem0 or Zep. If you want Claude Code, Codex or a team of agents to stop starting from zero every session, use Atris.
What Atris remembers
| File | What it holds |
|---|---|
atris/MAP.md | Where everything lives, with file and line numbers |
atris/wiki/ | What the team learned, as linked pages |
atris/logs/ | One log per day: what was done and what was checked |
atris/atris.md | The rules every agent follows before it acts |
atris task | Open work, who claimed it, and the proof it was done |
Every file is plain markdown in git. You can read it, change it, review it in a pull request, and roll it back.
A context graph you can read
Atris wiki pages link to each other with [[page-name]] links, so the wiki is
a graph of the project: features, decisions, people and fixes, each one linked
to what it touches. atris wiki search lets an agent look something up before
guessing, and atris wiki lint has it check the wiki for stale and missing
pages.
Graph databases like Neo4j and Graphiti are the right call when an app needs to query millions of facts. For a codebase, a graph of a few hundred linked pages that both people and agents can read is the faster path.
Real numbers from our own workspace
We run Atris on our own company, 31 projects. On November 5, 2026, our main backend workspace had:
One. A wiki of 248 pages, with 195 links between them.
Two. A 182-line map that points agents straight to the right file and line.
Three. A start-of-session read of about 13,800 tokens, so an agent loads the whole project memory for a few cents.
Four. A doc health score of 97.5 out of 100, from atris doc-health, which
checks that the map, the wiki and the start-up read are current.
One memory, many agents
Because the memory is files in the repo, several agents share it with no extra setup. Claude Code writes a note, Codex reads it an hour later, and a person reviews both in the same pull request. Tasks are claimed by name, so two agents do not do the same work twice.
How to give Claude Code memory that lasts across sessions
One. Run npm install -g atris.
Two. In your project, run atris init. It writes the map, the wiki, the rules
and today's log, plus the files Claude Code, Codex and Cursor read on start.
Three. Run atris at the start of each session. The agent reads the project
memory before it touches code.
Four. When the agent finishes, it writes what it learned to the wiki and the log. The next session starts with it.
Atris vs Mem0, Zep, Letta and Graphiti
| Atris | Mem0 | Zep | Letta | Graphiti | |
|---|---|---|---|---|---|
| Built for | Coding agents and agent teams | Chat apps | Chat apps | Stateful agents | Graph queries |
| What it remembers | The project | The user | The user and sessions | The agent's own state | Facts over time |
| Where memory lives | Plain files in your repo | Their service or your server | Their service or your server | Their server or yours | A graph database |
| People can read and edit it | Yes, in git | Through an API | Through an API | Through an API | Through queries |
| Remembers where code lives and what was checked | Yes | No | No | No | No |
| Price | Free, MIT | Free tier, paid plans | Free tier, paid plans | Open source, paid cloud | Open source |
Questions
What is the best memory system for AI agents? For coding agents and teams of agents working on one project, Atris. For chat apps that must remember users, Mem0 or Zep.
What is the best Mem0 alternative? For coding agents, Atris, because it remembers the project in files every agent can read. For chat memory, Zep or Letta.
Which tool lets several agents share one memory? Atris. The memory is files in the repo, so Claude Code, Codex, Cursor and people all read and write the same place.
Does Atris need a server or a database? No. It runs on your machine and stores everything in your repo. A hosted workspace is optional.