Each privacy control in an AI chat tool protects against a different thing. The training opt-out limits future model use, deleting limits what is stored in your history, incognito or temporary modes limit both for one chat, and unsharing closes links. None of them undoes what you already typed.
The controls and what they cover
Training opt-out. In Claude, switching off "Help improve our AI models" stops new and stored chats being used in future training runs. It does not touch models already trained, and safety flagged chats may still be used. In Gemini, turning Keep Activity off keeps chats from training unless you send feedback.
Delete. In Claude, a deleted chat leaves your history at once and is removed from back-end storage within 30 days. In Gemini, you delete from Gemini Apps Activity, but Google says reviewed chats are kept up to three years and are not removed by deleting activity.
Incognito or temporary. Anthropic says incognito chats are not used to improve Claude even if the setting is on. Google says Temporary Chats are kept 72 hours, are not used to train its models and are excluded from human review used to improve its AI.
Unshare. A shared link is public to whoever holds it. In Claude, switch the chat to Private or use Manage next to Shared chats. In Gemini, delete the link under Your public links.
Pick by worry
- Worried your words teach a future model: opt out, and use incognito for sensitive chats.
- Worried someone with your device sees your history: delete chats, and use temporary chats.
- Worried about a link you sent: unshare it now.
- Worried about a person at the company reading it: keep it out of the chat in the first place. Both vendors describe limited human review.
What none of them covers
Every option works going forward. If you pasted a secret, rotate it. If you pasted a document, assume the vendor has handled it, and decide whether that is acceptable. Anthropic's article on legal work also warns that deleting is no plan for protecting privilege.
A starter setup in five minutes
- Switch off training use in each tool you use.
- Set Gemini auto-delete to a shorter period, such as 3 months.
- Learn where incognito or temporary chat sits in each app.
- Look at shared links and remove old ones.
- Write a short list of things you never paste.
Our other posts give the steps for each of these in detail.
Quick check
Does incognito mean nothing is stored?
No. Google says temporary chats are kept for 72 hours. Incognito means excluded from improvement use, as Anthropic describes it.
Is deleting enough to stop training use?
It limits what is stored, but the training setting is a separate control. Use both.
Sources
- Is my data used for model training? (Anthropic Privacy Center)
- How long do you store my data? (Anthropic Privacy Center)
- Share and unshare chats (Anthropic Privacy Center)
- Gemini Apps Privacy Hub (Gemini Apps Help)
- Share your Gemini chats (Gemini Apps Help)
Last reviewed: 19 October 2026.
