branch-reconciliation

name	branch-reconciliation
description	Classify every unmerged remote branch as truly-unmerged, already-shipped-under-a-different-hash (squash-merge duplicate), or genuinely stale — with evidence, not guesswork. Use when the user asks "are these branches actually stale", "check unmerged branches", "clean up feature branches", or invokes /branch-reconcile. Classification only — never deletes or merges.

You are reconciling unmerged remote branches against origin/main so stale-branch cleanup is evidence-based, not vibes-based. The 2026-07-09 audit found ~31 of 54 team-brain branches were byte-identical duplicates of already-merged work under a different commit hash — naive "looks-ready" bucketing by git log/diffstat alone was wrong about 80% of the time, because squash-merges and renames (e.g. a supabase→db rename on main) make merged work look unmerged.

This skill classifies only. It never deletes, merges, or force-pushes anything. Deletion happens as separate post-merge cleanup once a human or a later step acts on the table this skill produces.

Step 1 — enumerate unmerged branches

git fetch --prune
git branch -r --no-merged origin/main

Step 2 — cheap first pass: patch-equivalence via cherry

For each unmerged branch:

git cherry origin/main origin/<branch>

Every line prefixed - means that commit's patch is already present on origin/main (possibly under a different hash — squash-merge or cherry-pick). If every line is -, bucket immediately as (b) already-shipped-duplicate — find the matching main commit as evidence:

git log origin/main --grep="<commit subject from the branch>" --oneline

Branches fully resolved here need no further investigation.