Best AI Memory Tools Across ChatGPT, Claude & Cursor
ChatGPT and Claude memory, MemoryPlugin, Supermemory, Mem0 and Unabyss compared on price, setup and who each one fits.
Every AI you use now remembers you, but only inside itself. The best AI memory tool depends on how many assistants you use: for one, turn on its built-in memory and stop there; for several, pick a tool that keeps your memory outside any single app and hands it to all of them.
What ChatGPT learned about you last month means nothing to Claude, and Cursor has never heard of either. Below: eight real options, compared on price, setup and where each one wins.
What is an AI memory tool?
An AI memory tool stores what an assistant should know about you and puts it back into new conversations, so you don't start from zero each time. Built-in memory does this inside one product. Cross-tool memory tools do it once and serve the result to several assistants, through a browser extension or the Model Context Protocol (MCP), the open standard Claude, ChatGPT and Cursor use to connect to outside tools.
Where the memory comes from matters as much. Most tools build it from your chats; Unabyss builds it from the apps your work happens in, which is the line between chat memory and personal context.
How do the best AI memory tools compare?
They split three ways: built-in memory that stays in one app, cross-tool tools for people who use AI, and memory infrastructure for people who build with it. Prices were checked on each vendor's pricing page on October 23, 2026.
| Tool | Best for | Works across AI tools | Built from | Price |
|---|---|---|---|---|
| Unabyss | Using Claude, ChatGPT and Cursor side by side | Yes, over MCP | Your work apps: Gmail, Calendar, Notion, Slack, GitHub, Linear and about 20 more | 7-day free trial, then Pro 89/mo |
| ChatGPT memory | People who mostly use ChatGPT | No | ChatGPT chats, saved memories, files and Gmail (Plus and Pro) | Free; [Go 20/mo |
| Claude memory | Claude users who want to see and edit what's stored | No | Claude chats, kept separate per project | Free; Pro 100/mo |
| Gemini memory | People who live in Google's apps | No | Gemini chats, saved info, connected Google apps | Free; AI Pro $19.99/mo |
| MemoryPlugin | Carrying chat memory between many chatbots | Yes, via browser extension and MCP | Memories you save, imported chat history | From $89/year, 7-day trial |
| Supermemory | Developers adding memory to apps and agents | Yes, via API, MCP and plugins | Whatever you or your app send it, plus connectors | Free; Pro 100/mo |
| Mem0 | Developers building agents | Via API; OpenMemory MCP runs locally | Whatever your app sends it | Free; Starter 249/mo |
| Basic Memory | Keeping notes in plain Markdown on your own machine | Yes, over MCP | Notes you and your AI write | Free locally; cloud from $15/seat/mo |
Is ChatGPT or Claude's built-in memory enough?
Yes, if one assistant does nearly all your work. It costs nothing extra and needs no setup; it just never leaves the app.
- ChatGPT has the most automatic memory: an auto-updated summary of you that you can edit, built from your chats and, on Plus and Pro, your files and Gmail (OpenAI Memory FAQ).
- Claude has the easiest memory to inspect: separate topics you can open, edit or delete, a separate memory per project, and on by default for Free, Pro and Max (Claude Help Center).
- Gemini is the most connected to your own data: with Personal Intelligence it reads Gmail, Calendar, Drive and Photos, and it can import chat history from ChatGPT and Claude in .zip files of up to 5 GB (Google).
All three keep memory inside their own walls. A one-time import from a rival isn't a sync: the next thing you tell ChatGPT stays in ChatGPT. The head-to-head is in Which AI Has the Best Memory?, and Claude's version in Claude Memory: How the Feature Works.
Which AI memory tools work across ChatGPT, Claude and Cursor?
Five tools do it properly, and they serve two different people: someone who uses AI tools all day, and someone building memory into an app of their own.
Unabyss
Unabyss is a personal context layer: shared memory for all your AI tools, built from the apps where your context already lives. You connect at least two sources, such as Gmail, Calendar, Notion, Slack, GitHub or Linear, and Unabyss extracts a structured picture of you, keeps it current as those sources change, and serves it over MCP to Claude, ChatGPT, Cursor, Claude Code, Codex and other MCP clients. You decide what each tool sees, per app and per file, and tools without MCP can take a Markdown export.
Because the context comes from your sources instead of your chats, it's there from the first session. In an August 2026 Unabyss benchmark, adding Unabyss to an assistant that already had the same tools connected cut cost by 36%, time by 38% and follow-up prompts by 60%, and the quality of accepted output rose from 7.7 to 8.9 out of 10 (What Structured AI Context Is Worth).
The trade-offs: there's no free plan, only a 7-day trial before Pro at $15 a month, and it's built around your work apps, not around archiving every chat you've had.
MemoryPlugin
MemoryPlugin keeps one memory across chatbots through a browser extension for Chrome and Safari plus an MCP server. It saves memories, imports past chat history, and says it works with 21-plus AI tools, including ChatGPT, Claude, Gemini, Grok and Perplexity (MemoryPlugin). It knows what you've said to AI, not what's in your inbox.
Supermemory
Supermemory is a memory engine for developers, used by more than 100,000 organizations by its own count (Supermemory). Beyond the API, it runs an MCP server for ChatGPT and Claude and plugins for coding agents such as Claude Code, Cursor and Codex (Supermemory). The detailed comparison: Supermemory vs Unabyss.
Mem0 and OpenMemory
Mem0 is a memory API for teams building agents, priced by requests rather than by person. Its OpenMemory MCP server is the individual-friendly part: it runs on your own machine and gives Cursor, Claude Desktop, Windsurf and Cline one shared memory, with nothing synced to the cloud (Mem0). You run the server yourself.
Basic Memory
Basic Memory keeps notes and decisions as a knowledge graph in plain Markdown on your own machine, open source, and serves them over MCP to Claude, Codex and Cursor (Basic Memory). It only knows what you or your AI wrote down.
Where is another tool the better choice than Unabyss?
Unabyss is the wrong pick in four common cases.
- You use one assistant. Its built-in memory is free and already there.
- You want chat history to follow you across many chatbots, including ones without MCP support in the browser. MemoryPlugin was built for exactly that.
- You're building an app or agent that has to remember its users. Supermemory or Mem0 give you an SDK and per-user memory; Unabyss is for the people using AI tools, not for developers shipping memory inside a product.
- You want everything local, in files you control. Basic Memory or OpenMemory keep it on your machine. If your notes already live in Obsidian, see the best AI plugins for Obsidian.
Unabyss is the better choice when what the AI needs to know lives in your work apps, changes every week, and has to reach Claude, ChatGPT and Cursor at once.
Will switching to a different AI fix the memory problem?
No, because every assistant starts out knowing nothing about you. Models are trained to be general, and memory is a feature added on top, so it fills in slowly and stays where it was built.
Leave ChatGPT for Claude and Claude improves once you set up its memory. Then you open Cursor, or a new tool launches, and you're a stranger again. Connecting Gmail to one assistant doesn't break the loop: a connector gives that tool a way to search a source, not an understanding of who you are. The better question is where your context lives, because a layer that travels makes the assistant a choice you can change freely. More in Why Doesn't AI Remember Me?
If you switch between Claude, ChatGPT and Cursor every day, start a 7-day Unabyss trial, connect two apps, and your next conversation in any of them starts with your context already loaded.
