The flag was right: apps/commandhq has its own composer and ships a verbatim copy of
background-job-prompt.ts, so handoffContract was still promising "the harness re-arms
you". Worse than stale — a mobile-armed watcher would have waited for a re-arm that
was never coming, firing once and silently stopping. Re-copied and diffed.
That is the third re-sync in one session, each caught only because I happened to be
reading the diff. A stale preamble typechecks, builds, and produces a job that runs,
so nothing catches it.
Proposes the fix: build the preamble on the server. It is a pure function of the
spec, both clients already assemble that spec locally, and the create endpoint could
take the spec instead of a finished prompt — one implementation, on the side that
owns the mechanism the text describes. displayText and cwd both drop out as things
the server can derive rather than be told.
Cost stated too: it puts prompt text behind a round trip. Not asked for tonight.
Also records why the mechanism changed, because it generalises: the synthetic turn
lost to the fact that this session's own watcher had been self-re-arming for hours
with zero failures. A measurement beat a hypothesis.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
pastilhasandClaude Opus 5
971a8bf0d4