Guide a PostHog engineer through spinning up, connecting to, running commands on, and mirroring local code to a remote devbox (a Coder workspace running the full PostHog stack). Use when asked to set up a devbox, start or connect to a devbox, configure remote dev, get gh CLI / Claude Code authed on a devbox, run a command on a devbox, sync a local checkout so you can edit locally while the stack runs remotely (devbox:sync), or diagnose why a devbox command fails. Covers the tailnet prerequisite, hogli devbox commands, Coder user secrets for auth, one-way local->remote sync via mutagen, and verifying with devbox:exec. How each dev personalizes their box is left to them.