Cursor turns pre-built cloud environments on by default on August 17

Cursor now prepares "ready-to-use copies of your development environment" in the background, by default once an hour, so a cloud agent forks a warm machine instead of booting, cloning repositories and running the install script at session start. Cursor reports that its own internal environments "boot 10x faster and time to first token is 3x faster." Neither figure comes with a baseline or a stated methodology. Blair McAlpine, senior engineer at Faire, is quoted saying the team kicks off "more than 2,000 automated agent runs a week without any manual prompting" and that broken builds "never take down the agent fleet," because agents keep starting from the last successful build while a broken one is debugged separately.

Why it matters: The default flips on August 17 for new and existing environments, and the migration is not a no-op. Builds work by filesystem snapshot, so work that can be done ahead belongs in the install command, credentials for private registries have to move to team or environment secrets because user secrets are deliberately kept out of builds, and the start command still runs per session for anything that must be fresh. If you run Cursor cloud agents, that is a config review with a date on it.