The cost of client communication is not typing. It is the context reload: remembering the thread, finding the number, checking what was promised. That part is the part that can be prepared.
The edit loop is the mechanism
A drafting tool that never learns produces the same slightly-wrong voice forever, and you rewrite every draft, and eventually you stop opening them. The edits are the signal: what you cut, what you softened, what you added that was missing.
So each run starts by reading the differences between the last batch of drafts and what was actually sent. Over a few weeks the gap narrows, and that narrowing is the entire value of the thing.
Set up from your own history
Before the first run, your existing sent mail and client messages are read to establish how you actually write to clients: length, formality, how you open, how you handle bad news. The starting point is your own history rather than a generic professional register.
Drafts, permanently
There is no setting that makes this send. Client communication is not a place for an autonomous agent, and the moment a tool can send on your behalf you have to review it with a different kind of attention, which costs more than the drafting saved.
Runs well with
Skills compound. These are the ones we usually install alongside it.