Clean Branches Agent Skill

Clean Branches - Delete Merged Local Branches

Clean up local branches by checking their GitHub PR status and deleting those

that have been merged.

Steps

• Fetch and list branches — Fetch the latest remote state, then get all

local branches except master:

git fetch origin master
git branch --format='%(refname:short)' | grep -v '^master$'

Show the list to the user. If no branches exist besides master, report that

and stop.

• Check merge status for each branch — Use multiple methods to detect

merges (including squash merges):

Method 1: Direct ancestry — Catches regular merges and fast-forwards:

git branch --merged origin/master --format='%(refname:short)'

Method 2: Squash merge detection via git cherry — For branches not caught

by method 1, check if all commits have equivalent patches in origin/master. A

- prefix means the patch already exists upstream:

git cherry -v origin/master <branch>

If ALL lines start with - (or output is empty), the branch has been

squash-merged.

Method 3: GitHub PR status (if gh is authenticated) — For remaining

branches:

# Check for merged PRs
gh pr list --head <branch> --state merged --json number,title,url

# Check for closed (not merged) PRs
gh pr list --head <branch> --state closed --json number,title,url,mergedAt

A PR is "closed without merge" when it appears in the closed list but has an

empty/null mergedAt field. If gh is not authenticated, skip this method.

Important: Always compare against origin/master (not local master) to

detect merges even when local master is stale.

• Categorize branches into these groups:

• Merged: Detected as merged by any method above → safe to delete
• Closed (not merged): PR was closed without merging → flag for user

decision

• No PR / Open PR: No PR found (and not detected as merged), or PR is

still open → skip

• Display categorized list — Show the user a summary table with:

• Branch name
• Category (Merged / Closed / No PR / Open)
• PR number and title (if available)
• Detection method (ancestry / squash / PR status)

• Confirm with user — Ask the user which branches to delete:

• Pre-select "Merged" branches for deletion
• Ask about "Closed (not merged)" branches individually
• Never auto-delete "No PR" or "Open PR" branches

• Delete confirmed branches — If currently on a branch being deleted,

switch to master first and fast-forward it:

git checkout master && git merge --ff-only origin/master
git branch -D <branch1> <branch2> ...

After deleting, prune stale remote tracking references:

git remote prune origin

• Report results — Summarize:
• How many branches were deleted
• Which branches were kept and why