With a stale local main, tg pr create --base main can include hundreds of upstream commits and create a PR whose diff fails with PatchTooLarge, as reported in https://tangled.org/jollywhoppers.com/witchsky.app/pulls/399/latest.
Resolve the selected branch against the target repository's published tip, require that commit locally, and verify that the patch is serveable before creating a ticket or submitting an update. Range errors now identify the source repository and both commits. CLI and MCP descriptions explain fetching the target remote first.
Regression tests use a real Git history with stale local main and verify that missing target history or failed patch preflight produces no remote writes.