Most of DF Code is configured per workspace, but a couple of things are set once and inherited everywhere: a fallback working directory, used when a run happens somewhere that has no worktree of its own yet, and which CLI coding tool actually runs on your behalf.
The coding tool is the consequential one. DF Code drives an existing CLI rather than talking to a model itself, so whichever Connector you pick here is what every run in every workspace spawns — unless a particular workspace overrides it (see Choosing a connector per workspace).
Note that the fallback directory is not where your workspaces live — an activated workspace always gets its own checkout in DF Code's own data directory (see Workspaces & Threads), and that location is not something you set here.
Everything here is a default rather than a rule. A workspace that needs something different can say so, and nothing you set here retroactively changes work that has already happened.