Prune

1.3 Confirm with user

Present the detected upstream remote and target branch. Ask the user to confirm or override. Example:

Detected upstream: upstream → akkadotnet/akka.net, target branch: dev Is this correct?

Phase 2: Scan Branches

2.1 Fetch latest

git fetch <upstream> --quiet
git fetch origin --prune --quiet

2.2 Enumerate all branches

Run git branch -vv --no-color to get all local branches with:

• Branch name
• Short SHA
• Tracking remote (if any)
• Ahead/behind status
• Last commit subject

Also run git branch -r --no-color to get remote branches on origin (excluding upstream branches — those aren't ours).

2.3 Collect metadata

For each branch, record:

• name: branch name
• sha: short SHA of the tip commit
• tracking: which remote branch it tracks (if any)
• has_local: whether a local branch exists
• has_remote: whether origin/<name> exists
• last_commit_subject: the commit message of the tip
• is_current: whether it's the currently checked-out branch

Skip tracking branches (dev, main, master) — never suggest deleting these.

Phase 3: Categorize Each Branch

For each non-tracking branch, determine its category. Try these checks in order - the first match wins.

3.1 Check: Is it the current branch?

If is_current is true, category = current (never delete).

3.2 Check: Is it a rename of another branch?

Compare the SHA against all other branches. If another branch has the exact same SHA and a different name, this is likely an old name.

Category = renamed if:

• Same SHA as another branch
• The other branch has a remote tracking branch or an open PR
• This branch does NOT have a remote tracking branch or open PR

Record which branch it was renamed to.

3.3 Check: Is it merged upstream?

Step A — Try git branch --merged:

git branch --merged <upstream>/<target>

If the branch appears in this list, it was merged (not squash-merged). Category = merged.

Step B — Try PR-based verification (for squash merges):

If the branch was NOT in the --merged list, check if it has a merged PR.

Use available tools to search for PRs from the branch. Try these in order:

• GitHub MCP tools — search for PRs with the branch name as head ref
• Azure DevOps MCP tools — search for PRs with the branch as source ref
• gh CLI — gh pr list --head <branch-name> --state merged --json number
• az CLI — az repos pr list --source-branch <branch-name> --status completed
• If none are available, skip PR-based verification (see Error Handling)

If a merged PR is found, verify the squash commit exists on the target branch:

git log --oneline <upstream>/<target> --grep="#<pr-number>" -1

If found, category = merged. Record the PR number.

Step C — No merged PR found:

Continue to next check.

3.4 Check: Does it have an open PR?

Search for open PRs from this branch using available tools (GitHub MCP, Azure DevOps MCP, gh CLI, or az CLI - same priority as step 3.3B).

If found, category = active_pr. Record the PR number.

3.5 Fallback: Unknown

If none of the above matched, category = unknown.

Phase 4: Present for Review

Group branches by action and present using a card-per-branch format.

Output format

DELETE (<count> branches)
═════════════════════════

  Merged PRs (local + origin)
  ───────────────────────────

  ✓ <branch-name>
    PR #<number> merged │ <sha>
    ├─ delete: git branch -D <branch-name>
    ├─ delete: git push origin --delete <branch-name>
    └─ undo:   git branch <branch-name> <full-sha>

  Renamed (old names)
  ───────────────────

  → <old-branch-name>
    Renamed to <new-branch-name> │ <sha>
    ├─ delete: git branch -D <old-branch-name>
    └─ undo:   git branch <old-branch-name> <full-sha>


UNKNOWN (<count> branches — need your input)
════════════════════════════════════════════

  ? <branch-name>
    No PR found │ local only │ <sha>
    Last commit: "<commit subject>"


KEEPING (<count> branches)
══════════════════════════

  ● <branch-name>    PR #<number> open
  ─ dev
  ─ master

Presentation rules

1. DELETE section first — this is what the user is here for
2. Group within DELETE by sub-category: merged PRs, abandoned, renamed
3. For each deletable branch show:
   • Status icon: ✓ (merged), ✗ (abandoned), → (renamed)
   • Why it's safe to delete (PR number, rename target)
   • Exact delete commands (local + remote if applicable)
   • Exact undo command (git branch from SHA)
4. UNKNOWN section — branches where the skill couldn't determine status. Show the last commit subject to help the user decide.
5. KEEPING section — brief, one line per branch. Just so the user can verify nothing was miscategorized.
6. Use -D (force) for delete commands, not -d, because squash-merged branches won't be detected as merged by git.

Phase 5: Confirm and Execute

5.1 Ask for approval

After presenting the view, ask the user which branches to delete:

• "Delete all in the DELETE section?"
• "Delete all + some/all unknowns?"
• "Let me pick individually"

5.2 Execute deletions

For approved branches:

1. Switch to a safe branch first if the current branch is being deleted (switch to the target branch, e.g., dev)
2. Delete local branches: git branch -D <name>
3. Delete remote branches: git push origin --delete <name>
4. Report each deletion result (success/failure)

5.3 Post-cleanup

Run git fetch origin --prune to clean up stale remote tracking refs.

Report final state: how many branches remain.

Error Handling

• PR tools unavailable: If no GitHub MCP, Azure DevOps MCP, gh CLI, or az CLI is available, skip PR-based verification. Categorize all non---merged branches as unknown and note that PR status couldn't be checked.
• Remote deletion fails: Report the error but continue with remaining deletions. The branch may have already been deleted (e.g., by GitHub's auto-delete on merge).
• Current branch in delete list: Switch to target branch first. If the switch fails, skip that branch and report the error.

Quick Reference

/prune
  1. Detect repo layout  →  find upstream remote + target branch
  2. Scan branches       →  enumerate local + remote, collect metadata
  3. Categorize          →  merged / renamed / active PR / unknown
  4. Present             →  card-per-branch grouped by action
  5. Confirm + execute   →  user approves, delete local + remote