Hard rules

Do not create branches, commit, push, or open PRs until the user approves the split plan.
Never discard user work. No destructive git commands (reset --hard, clean -fdx, branch deletion, force-push, history rewrite) without explicit approval.
Always save a recoverable snapshot before moving work around.
Stage only named files or hunks. No git add . / git add -A.
Stacking is organizational only. Earlier slices may exclude hunks or files that depend on work in later slices (for example, omit an enqueue until the worker lands). What is prohibited is modifying, adding, or stubbing code in intermediate slices: no rewrites, no stand-ins, no new logic. Every line in a slice must be an exact, unchanged excerpt from the existing work; excluded lines appear unchanged in a later slice.
Always use a linear gh stack, even when two slices have no compile-time dependency and could ship as parallel PRs off main. Order foundations before consumers when dependencies exist; otherwise order by reviewer concern or logical grouping.

1. Gather context

Compare all work (committed on the branch plus unstaged and staged) against the default branch.

Recover intent from branch name, Linear/git issue links, chat history, and diff themes.

Read gh stack --help if you are unsure of a command flag.