Why does ChatGPT (or Claude) forget what I told it?

Because each chat is its own separate conversation. A new chat starts more or less from scratch, and a very long chat can lose track of what you said at the beginning. It isn’t ignoring you, and you can fix most of it with two settings and one good habit.

Why does a new chat start from scratch?

Think of each chat as a separate phone call to a helpful stranger. During the call they follow everything. Hang up and ring again, and you may get someone who has never heard of you.

That’s how these tools were built. Everything inside one chat is in front of the AI. Anything in a different chat isn’t, unless a memory feature brings it across (more on that below).

So if you told ChatGPT about your daughter’s nut allergy last Tuesday, in a different chat, don’t be surprised if today’s meal plan includes peanut butter.

Why does it forget things in the same chat?

AI can only hold so much in mind at once. Think of it as a desk. Every message, every answer and every document you upload goes on the desk. When the desk is full, the oldest papers get pushed to the back, or squashed down into a short summary to make room.

That’s why, in a very long chat, the AI may:

• Forget an instruction you gave at the start (“keep it under 100 words”)
• Mix up details from earlier
• Start repeating itself

It’s a sign the chat has got too long, not that you’ve done something wrong.

The fix: ask for a summary, then start a new chat and paste it in.

Summarise everything we've agreed so far in a short list,
so I can carry on in a new chat.

Doesn’t it have a memory?

Yes, both tools now have a memory feature, and it helps. But it works more like a notebook than a recording.

• ChatGPT can keep “saved memories” (a list of useful facts about you) and can also refer back to your past chats. Look in Settings, under Personalization.
• Claude builds up a memory of useful details as you chat. Look in Settings, under Memory.

In both, the AI decides what’s worth noting. It won’t keep every word, and it may not jot down the thing you care about most. So three tips:

1. Check it’s switched on. It isn’t always on by default, and some parts of it depend on your plan.
2. Tell it what to keep. Just say so:

Please remember that I'm vegetarian and I live in Leeds.

3. Have a look now and then. In the same settings you can see what it has remembered, and delete anything that’s wrong or that you’d rather it didn’t keep.

One more thing. Both tools have a private mode (ChatGPT calls it a temporary chat, Claude calls it an incognito chat). Nothing from those chats gets remembered. That’s the point of them, so use them when you want a chat forgotten.

How do I tell it about me just once?

Both tools have a box in Settings where you describe yourself and how you like answers. ChatGPT calls it custom instructions. Claude has an “instructions” box in your profile. Whatever you write there applies to every new chat, so it’s the most reliable way to stop repeating yourself.

A few lines is enough: what you do, who’s in your household, and how you like things written. Our setup guides walk you through it for ChatGPT and Claude.

What’s the best fix for ongoing jobs?

Projects. A Project is a folder for one ongoing thing: planning a wedding, running the club newsletter, sorting out a house move. Both ChatGPT and Claude have them, including on the free plans (with some limits).

You give the Project two things:

• Instructions: the background, written once. “We’re moving from Bristol to York in March. Budget is tight. Two children, one dog.”
• Files: the documents it should know about, like the survey or the removal quotes.

Every chat you start inside that Project already knows all of it. No more explaining from the top each time.

Is it risky that it remembers things?

It’s worth a thought. Memory makes AI more useful, but it does mean details about you are stored in your account. You’re in control: you can view, edit and delete what’s remembered, or switch memory off entirely.

A sensible rule is to keep bank details, passwords and other people’s private information out of your chats altogether. See Is AI safe? for the full list.

The short version

• New topic, new chat.
• Long chat going wrong? Ask for a summary and start fresh.
• Things that are always true about you go in your settings.
• Ongoing jobs go in a Project.

Next step

Our free AI Setup Checklist walks you through the memory and “about me” settings in under 30 minutes, so you can stop repeating yourself.