Create branch

Get onto the working branch

All work happens on a prefixed feature branch — never on a protected branch (main/master/release/*). The safety hook blocks pushes to protected branches.

Two paths — know which one you're in:

• In the factory (the normal case): the runner has ALREADY created your gaffer/… branch and checked you out onto its worktree. You do not create or switch branches — you verify you're on the right kind of branch and stop if you aren't. See Factory path below.
• Standalone / non-factory: no branch was prepared for you, so you create one yourself with the exact convention. See Standalone path below.

Factory path — VERIFY, do not create

The runner already created and checked you out onto your gaffer/ticket-<number>-… worktree branch. Your job is to confirm the ground is safe, not to branch:

1. Confirm you're on a non-protected branch. Check the current branch (git branch --show-current / git rev-parse --abbrev-ref HEAD). It must NOT be main/master/release/*. The gaffer/ prefix is expected.
2. Do NOT run git switch -c / git checkout -b. A branch already exists; creating another one diverges from the worktree the runner set up and the factory expects.
3. Check the working tree is clean. Run git status --porcelain. If it is dirty — uncommitted or untracked state left over from a prior partial run on this worktree — do not branch over it or start editing on top of it. Stop and mark_ticket_blocked with a clear reason ("worktree dirty on arrival: <files>"); a human resolves the stale state. Fabricating a clean start over dirty state corrupts the delivery.
4. If you are somehow on a protected branch (the runner's setup didn't take), do not "fix" it by creating your own branch — mark_ticket_blocked and report it, because the environment isn't what the factory guarantees.

Once you've verified a clean tree on a non-protected gaffer/… branch, implement directly on it. The rest of this skill (the naming convention) applies to the standalone case.

Standalone path — create the branch yourself

Only when no branch was prepared for you (running this skill outside the factory): build the name from the convention below, confirm a clean tree, then git switch -c <name>.

The branch name (exact convention)

Use this shape, exactly:

gaffer/ticket-<number>-<short-slug>

• gaffer/ prefix is mandatory. The safety hook and the factory both expect it; a branch without it is wrong and can fail review or get hook-blocked.
• ticket-<number> — the literal word ticket, a hyphen, then the ticket number (e.g. ticket-412).
• <short-slug> — a lowercase, hyphenated slug derived from the ticket title: ≤ ~6 words, no spaces, no uppercase, no punctuation beyond the hyphens.

Example: ticket #412 "Add rate limiting to login" → gaffer/ticket-412-add-rate-limiting.

Wrong (do not produce these): ad-hoc names, UUIDs or random suffixes (gaffer/3f9a-…), the prefix omitted, or ticket/… without the gaffer/ prefix.

Steps (standalone path only)

1. Confirm the base branch from the context packet (e.g. default_branch). Branch from it unless the ticket explicitly says otherwise.
2. Build the branch name as gaffer/ticket-<number>-<short-slug> per the convention above — ticket number from the claimed ticket, slug from its title.
3. Confirm the current tree is clean and based on the right ref before branching. If git status --porcelain is non-empty, stop (mark_ticket_blocked) rather than branching over uncommitted state.
4. Create and switch to the branch with the repo's VCS (git switch -c <name>). Do not push yet — pushing happens at review time, and force-push is blocked.
5. Verify you are on the new branch and not on a protected one before editing.

In the factory path you skip steps 2 and 4 entirely — the branch already exists. You only verify (current branch is a non-protected gaffer/…) and confirm a clean tree.

Rules

• In the factory, VERIFY — never git switch -c. The runner already created and checked you out onto your gaffer/… worktree branch; creating another diverges from it. Branch creation is for the standalone case only.
• Use the exact convention: gaffer/ticket-<number>-<short-slug>. The gaffer/ prefix is mandatory — the safety hook and factory depend on it. Ad-hoc names, UUIDs, or ticket/… without the prefix are wrong and can fail review.
• A dirty working tree on arrival is a blocker, not a thing to branch over. Leftover uncommitted/untracked state from a prior partial run → mark_ticket_blocked, don't build on top of it.
• Never create or commit on a protected branch (main/master/release/*) — the hook will block the push and the work will be wasted.
• One ticket, one branch. Do not reuse a branch from an unrelated ticket.
• Do not install dependencies or write outside the repo — the hook blocks both.