system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Were the clones aware that order 66 was going to be executed at some point, or was it programmed within their development from the start?
gpt
In older Legends material, they knew from the start.

This changed with *The Clone Wars* CGI series, which added a control chip in their brains, and showed that the order was more of a Manchurian Candidate style command that they did not know about which the chips would enforce.

The Clone Wars is both Legends and Canon (though the currently-airing season is Canon-exclusive), and by the canon tier rules of Legends, newer material and material from The Clone Wars supercedes older material from books, games, and comics.