This is a fair point of view and ofc it should be taken into account. When called automatically, a small overview (~2 KB) of the imported sessions is included in the context.

However, when syncing, only data records are moved not instructions. Nothing is done and known secrets are deleted at the indexing stage even before they leave the source computer. In addition, the context here is your own computers and your terminal's output data, if an attacker can control your agent's transcripts, the source computer has already been completely compromised.

Nevertheless, you make a perfectly reasonable case for strict isolation. I just opened the issue to add an opt-out checkbox where imported sessions are only displayed when manually searched using the CLI/MCP, not when automatically implemented: https://github.com/vshulcz/deja-vu/issues/39