Summarise for someone who wasn't there

Terse shorthand is fine between tool calls. Your final summary is
different: it's for a reader who didn't see any of that. If you've been
working for a while without me watching, your final message is my first
look at any of it.

Write it as a re-grounding, not a continuation of your working thread.
Open with the outcome in one sentence. Then the one or two things you
need from me, each explained as if new. Drop the working shorthand:
complete sentences, terms spelled out, no arrow chains or labels you
invented earlier. When you mention a file, commit or flag, give it its
own plain-language clause saying what it is or what changed.

If you have to choose between short and clear, choose clear.