Review found that the first cut traded the duplicate-delivery bug for a worse one, and disproved its own load-bearing safety claim by experiment. Expiry was unreachable. _claim_parked touched the mtime on every re-claim and _release_claim backdated to exactly now minus the stale threshold, so a file's age hovered around 121 seconds and never approached the 7-day expiry. The attempt count in the filename therefore bounded nothing: an undeliverable batch (revoked key, proxy 403, oversized event) lived on disk forever, and because spawn_flush starts a sender whenever a .sending file exists, it spawned a detached Python process on every hook, MCP call and CLI invocation, forever. The old code self-healed here, so this was a regression. Expiry now gates on the attempt budget, which is the thing that actually accumulates; age stays only as a backstop for files that never carried an attempt marker. The attempt parser sniffed for a leading "a", which also matches a hex id like a1234567, so a legacy telemetry-<pid>-<hex>.sending file parsed as attempt 1234567 and was deleted unsent on the first flush after upgrade — precisely the population this PR is meant to protect. Anchored on field position instead. The rewrite was not durable: no fsync before the rename, and _drain unlinked any claim that parsed to zero events. A crash between write and rename left the claim empty, and the next flush deleted it. Now fsynced, and a non-empty file that parses to nothing is quarantined as .corrupt rather than destroyed. read_text raises UnicodeDecodeError on a torn file, which `except OSError` does not catch. flush() runs from a bare `finally:` in flush_worker, so the exception also skipped the handoff cleanup and left it stuck in .running. The per-batch rewrite's return value was discarded, so a failed rewrite let the loop continue as though progress had been recorded — reintroducing the exact duplicate delivery this PR exists to fix. .partial files orphaned by a crash between write and rename matched no glob in the module and were never cleaned up. Also replaces the heartbeat test, which asserted `SEND_TIMEOUT * 4 < CLAIM_STALE_SECONDS` — two constants, executing none of the code under test. It now drives the real rewrite and watches the mtime move. New tests cover expiry being reachable, legacy filename parsing, torn-claim quarantine, failed-rewrite behaviour and debris sweeping. 64 core tests, 199 host tests. Claude-Session: https://claude.ai/code/session_01C7tEmH86HAr7GoAAKCEHZb
Learn more · Join Discord · Demo
📄 Benchmarking Mem0's token-efficient memory algorithm →
New Memory Algorithm (April 2026)
| Benchmark | Old | New | Tokens | Latency p50 |
|---|---|---|---|---|
| LoCoMo | 71.4 | 92.5 | 7.0K | 0.88s |
| LongMemEval | 67.8 | 94.4 | 6.8K | 1.09s |
| BEAM (1M) | — | 64.1 | 6.7K | 1.00s |
| BEAM (10M) | — | 48.6 | 6.9K | 1.05s |
All benchmarks run on the same production-representative model stack. Single-pass retrieval (one call, no agentic loops) at a top_200 retrieval budget. Scores reflect Mem0's managed platform, which includes proprietary optimizations not available in the open-source SDK; open-source users should expect directionally similar gains but not identical numbers.
What changed:
- Single-pass ADD-only extraction -- one LLM call, no UPDATE/DELETE. Memories accumulate; nothing is overwritten.
- Agent-generated facts are first-class -- when an agent confirms an action, that information is now stored with equal weight.
- Entity linking -- entities are extracted, embedded, and linked across memories for retrieval boosting.
- Multi-signal retrieval -- semantic, BM25 keyword, and entity matching scored in parallel and fused.
- Temporal Reasoning -- time-aware retrieval that ranks the right dated instance for queries about current state, past events, and upcoming plans.
See the migration guide for upgrade instructions. The evaluation framework is open-sourced so anyone can reproduce the numbers.
Research Highlights
- 92.5 on LoCoMo -- +21 points over the previous algorithm
- 94.4 on LongMemEval -- +27 points, with 98.2 on assistant memory recall
- 64.1 on BEAM (1M) -- production-scale memory evaluation at 1M tokens
- Read the full paper
Introduction
Mem0 ("mem-zero") enhances AI assistants and agents with an intelligent memory layer, enabling personalized AI interactions. It remembers user preferences, adapts to individual needs, and continuously learns over time—ideal for customer support chatbots, AI assistants, and autonomous systems.
Key Features & Use Cases
Core Capabilities:
- Multi-Level Memory: Seamlessly retains User, Session, and Agent state with adaptive personalization
- Developer-Friendly: Intuitive API, cross-platform SDKs, and a fully managed service option
Applications:
- AI Assistants: Consistent, context-rich conversations
- Customer Support: Recall past tickets and user history for tailored help
- Healthcare: Track patient preferences and history for personalized care
- Productivity & Gaming: Adaptive workflows and environments based on user behavior
🚀 Quickstart Guide
Sign up as an agent
AI agents can mint a working Mem0 API key in under five seconds — no email, no dashboard, no OTP. Four commands end-to-end:
# 1. Install
npm install -g @mem0/cli # or: pip install mem0-cli
# 2. Sign up as an agent (replace `claude-code` with your name)
mem0 init --agent --agent-caller claude-code
# 3. Add a memory
mem0 add "I am using mem0"
# 4. Search
mem0 search "am I using mem0"
The human owner can claim the account later with mem0 init --email <their-email> — same key, memories preserved. Full guide: Sign up as an agent.
| Library | Self-Hosted Server | Cloud Platform | |
|---|---|---|---|
| Best for | Testing, prototyping | Teams running on their own infrastructure | Zero-ops production use |
| Setup | pip install mem0ai |
docker compose up |
Sign up at app.mem0.ai |
| Dashboard | -- | Yes | Yes |
| Auth & API Keys | -- | Yes | Yes |
| Advanced Features | -- | Teasers | All included |
Just testing? Use the library. Building for a team? Self-hosted. Want zero ops? Cloud.
Library (pip / npm)
pip install mem0ai
For enhanced hybrid search with BM25 keyword matching and entity extraction, install with NLP support:
pip install mem0ai[nlp]
python -m spacy download en_core_web_sm
Install sdk via npm:
npm install mem0ai
Self-Hosted Server
Note: Self-hosted auth is on by default. Upgrading from a pre-auth build? Set
ADMIN_API_KEY, register an admin through the wizard, orAUTH_DISABLED=truefor local dev only. See upgrade notes.
# Recommended: one command — start the stack, create an admin, issue the first API key.
cd server && make bootstrap
# Manual: start the stack and finish setup via the browser wizard.
cd server && docker compose up -d # http://localhost:3000
See the self-hosted docs for configuration.
Cloud Platform
- Sign up on Mem0 Platform
- Embed the memory layer via SDK or API keys
- Using hosted Qdrant vectors? See the Platform migration guide to import them into Mem0 Platform.
CLI
Manage memories from your terminal:
npm install -g @mem0/cli # or: pip install mem0-cli
mem0 init
mem0 add "Prefers dark mode and vim keybindings" --user-id alice
mem0 search "What does Alice prefer?" --user-id alice
See the CLI documentation for the full command reference.
Agent Skills
Teach your AI coding assistant (Claude Code, Codex, Cursor, Windsurf, OpenCode, OpenClaw, and any tool that supports the skills standard) how to build with Mem0. Two categories:
Reference skills — always on (SDK knowledge loaded into the assistant's context):
npx skills add https://github.com/mem0ai/mem0 --skill mem0
npx skills add https://github.com/mem0ai/mem0 --skill mem0-cli
npx skills add https://github.com/mem0ai/mem0 --skill mem0-vercel-ai-sdk
Pipeline skills — run on demand (execute an end-to-end workflow in an existing repo):
npx skills add https://github.com/mem0ai/mem0 --skill mem0-integrate
npx skills add https://github.com/mem0ai/mem0 --skill mem0-test-integration
npx skills add https://github.com/mem0ai/mem0 --skill mem0-oss-to-platform
Use /mem0-integrate to wire Mem0 into an existing repo via a test-first pipeline, then /mem0-test-integration to verify. Use /mem0-oss-to-platform to migrate an existing project from Mem0 OSS to the hosted Platform SDK. See the skills catalog or Vibecoding with Mem0 for the full picture.
Basic Usage
Mem0 requires an LLM to function, with gpt-5-mini from OpenAI as the default. However, it supports a variety of LLMs; for details, refer to our Supported LLMs documentation.
Mem0 uses text-embedding-3-small from OpenAI as the default embedding model. For best results with hybrid search (semantic + keyword + entity boosting), we recommend using at least Qwen 600M or a comparable embedding model. See Supported Embeddings for configuration details.
First step is to instantiate the memory:
from openai import OpenAI
from mem0 import Memory
openai_client = OpenAI()
memory = Memory()
def chat_with_memories(message: str, user_id: str = "default_user") -> str:
# Retrieve relevant memories
relevant_memories = memory.search(query=message, filters={"user_id": user_id}, top_k=3)
memories_str = "\n".join(f"- {entry['memory']}" for entry in relevant_memories["results"])
# Generate Assistant response
system_prompt = f"You are a helpful AI. Answer the question based on query and memories.\nUser Memories:\n{memories_str}"
messages = [{"role": "system", "content": system_prompt}, {"role": "user", "content": message}]
response = openai_client.chat.completions.create(model="gpt-5-mini", messages=messages)
assistant_response = response.choices[0].message.content
# Create new memories from the conversation
messages.append({"role": "assistant", "content": assistant_response})
memory.add(messages, user_id=user_id)
return assistant_response
def main():
print("Chat with AI (type 'exit' to quit)")
while True:
user_input = input("You: ").strip()
if user_input.lower() == 'exit':
print("Goodbye!")
break
print(f"AI: {chat_with_memories(user_input)}")
if __name__ == "__main__":
main()
For detailed integration steps, see the Quickstart and API Reference.
🔗 Integrations & Demos
- ChatGPT with Memory: Personalized chat powered by Mem0 (Live Demo)
- Browser Extension: Store memories across ChatGPT, Perplexity, and Claude (Chrome Extension)
- Langgraph Support: Build a customer bot with Langgraph + Mem0 (Guide)
- CrewAI Integration: Tailor CrewAI outputs with Mem0 (Example)
📚 Documentation & Support
- Full docs: https://docs.mem0.ai
- Community: Discord · X (formerly Twitter)
- Contact: founders@mem0.ai
Citation
We now have a paper you can cite:
@article{mem0,
title={Mem0: Building Production-Ready AI Agents with Scalable Long-Term Memory},
author={Chhikara, Prateek and Khant, Dev and Aryan, Saket and Singh, Taranjeet and Yadav, Deshraj},
journal={arXiv preprint arXiv:2504.19413},
year={2025}
}
⚖️ License
Apache 2.0 — see the LICENSE file for details.