A lawyer wants help structuring an argument. The underlying file contains client names and financial details. They would prefer this work not contribute to improving future models, and they are willing to change how they work but not their standing account settings. What is the soundest approach?

The principle — two distinct concerns are in play and each has its own control. One is whether the conversation contributes to improving models; the other is what personal detail you place into it at all. Conflating them leads to a solution that answers one and quietly leaves the other.

Why the key is correct — it addresses both. Anthropic states that Incognito chats are not used to improve Claude even when Model Improvement is enabled in Privacy Settings, which handles the training concern per conversation and leaves standing account settings untouched — exactly the constraint given. Separately, Anthropic recommends being thoughtful about sharing highly sensitive personal details, naming financial information and confidential documents among them. Removing client names and figures before pasting responds to that, and it costs nothing here: structuring an argument depends on the shape of the reasoning, not on who the client is. The lawyer gets the help they came for while neither concern is left unanswered.

Why the others are wrong — deleting afterwards is not the documented exclusion mechanism and does nothing about what was entered. Relying on Incognito alone answers the training question and ignores standing guidance about sensitive material, which applies whatever the chat type. And switching off model improvement account-wide was ruled out by the constraint, while still leaving client detail in the conversation.

Remember this — Incognito decides how the conversation is used; redaction decides what is in it. Different questions, different answers.

Sources — Anthropic's article on data used for model training, and its guidance on sensitive data.