Exit codes

arc uses structured exit codes so scripts can react to specific conditions without parsing stderr.

Code	Name	Meaning	What to do
0	Success	Command completed successfully
1	Error	General error	Read stderr for details
2	Not initialized	No stack found in the current repo	Run arc init
3	Rebase conflict	A branch could not be rebased cleanly	Resolve conflict, then arc rebase --continue or arc rebase --abort
4	GitHub API failure	gh returned an error	Check gh auth status, verify network, retry
5	Invalid arguments	Bad flag combination or missing required argument	Read stderr for the specific error
6	Setup check failed	Environment not configured	Run arc setup
7	Pre-hook failed	A pre-* hook returned non-zero	Fix the check, or pass --skip-hooks

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Using exit codes in scripts

arc sync
status=$?

case $status in
  0) echo "Sync complete" ;;
  3) echo "Conflict — resolve and run arc rebase --continue" ;;
  4) echo "GitHub API error — check gh auth status" ;;
  *) echo "Unexpected error $status" >&2; exit $status ;;
esac

# Abort the pipeline if arc is not initialized
arc status >/dev/null 2>&1 || { echo "Run arc init first"; exit 1; }

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Notes

• Exit code 3 (conflict) is not an error — it is the expected outcome when a rebase hits conflicting changes. Scripts should branch on it, not treat it as a failure.
• arc rebase --continue and arc rebase --abort both exit 0 on success.
• --dry-run always exits 0 if the plan was computed successfully, regardless of what the plan contains.