A command line cut across writes runs once whole, and look/exec answer per open

A mount cuts a write at its message size, and each piece ran on its own: a
line cut at the boundary ran as shell commands and a 50 KB Edit block
broke. An open of look, exec, tagexec, any ctl or a column's exec now keeps
an unfinished last line, or an Edit block still open, until its next write
or its release, and never runs a fragment. The same open record holds what
its last write touched, which a read on it answers (as /net/tcp/clone
does); an open that never wrote reads the session's last as of its open.
A release that runs a held line waits for quiet and counts as a change;
a clicked line with a control character is still refused at its write.
Tested in unit tests, fs.py (python client, 8 KiB) and selfmount.py (the
kernel mount, a 1000-line seq burst and a 50 KB Edit block).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/.agents/skills/pardes-9p/SKILL.md b/.agents/skills/pardes-9p/SKILL.md
index 9ec46084..1142efa9 100644
--- a/.agents/skills/pardes-9p/SKILL.md
+++ b/.agents/skills/pardes-9p/SKILL.md
@@ -140,7 +140,11 @@ created or removed, and no read creates anything.
 `look` and `exec` are the editor's two clicks, one per line of a write, at the
 active pane from the root and at that pane from `$m/pane/<n>/look` and
 `$m/pane/<n>/exec`. Reading any of them answers the serials the last command
-made, or the pane it focused or acted on. A command that fails is reported in
+made, or the pane it focused or acted on: an open's own last write's, or, on
+an open that never wrote, the session's last. With other clients about,
+write and read one open (`exec 3<>$m/look; echo x >&3; cat <&3; exec 3<&-`).
+Each command line runs once whole, however a mount cuts a big write; a last
+line with no newline runs when the open closes. A command that fails is reported in
 the editor, not as a write error, so inspect the resulting pane, index, message
 or screen; only a malformed line fails the write itself. A word no builtin
 knows (a typo included) is a command line: written at a terminal at its