Review P3-1: a "No such file or directory" line from another program
(cat, ls) no longer counts. Only bash's "line N:", dash's "N:" and env's
quoted form do.
P3-2: a name with a run of 16 letters and digits looks like a key, so it
stays in the run's private stderr instead of the reply.
P3-3: a 16 KiB stderr window that starts mid-file drops its partial first
line, so a cut name ("aude") isn't reported.
P3-4: CRLF lines read the same as LF lines.
P3-5: tests for the name check (tokens without spaces, key-shaped names),
for a cat line, and for the window boundary through the runner.
A claude-code turn on a Console started without MOSAIC_CLAUDE_BIN failed
with a bare "adapter exited 127". The sandbox binds /usr, so the wrapper
/usr/bin/claude is visible, but its exec target /opt/claude-code/bin/claude
isn't bound, and the shell exits 127.
On exit 127 the runner now reads the tail of the turn's stderr, finds the
shell's "not found" line (bash, dash, env) and adds the program's basename:
"adapter exited 127 (command not found: claude)". It never shows a host
path or anything that isn't a plain program name; a 127 without such a
line keeps the bare reason.
The deploy side (MOSAIC_CLAUDE_BIN on the Console unit) is a Lead-owned
script change, written up in the lane report.
jason.woltje