Exit codes

Every command exits with a code you can branch on. Nothing prints an error to stdout, so a script can read stdout and check $? independently.

Code	Meaning	Retry?
`0`	Success, including "nothing changed"	-
`1`	Generic failure	Maybe
`2`	Usage: bad flags, unknown filter key, missing location	No, fix the command
`3`	Auth: no session, session rejected, MFA pending	No, log in again
`4`	Not found: item, user, conversation or watch	No
`5`	Blocked or rate limited (CloudFront 403, HTTP 429)	Yes, after a wait
`6`	Network or timeout	Yes
`7`	API changed: a known endpoint returned an unexpected shape	No, report it
`130`	Interrupted	-

Using them

if ! wallapop auth refresh; then
  echo "session expired" >&2
  exit 1
fi

Back off on the retryable codes and stop on the rest:

wallapop watch check --all
case $? in
  0) ;;
  5|6) sleep 300; wallapop watch check --all ;;
  *)  exit 1 ;;
esac

Pair with the error envelope

--error-format json prints a stable category string next to the code. Branch on that when you log failures. See Output.