kit-task-start

name	kit-task-start
description	Start work on a GitHub issue — thin caller of `cckit start <N>`. Creates an isolated, bootstrapped worktree + `<kind>/<N>-<slug>` branch from the base branch and marks the issue In Progress on the board (if enabled). Worktree-first — there is no in-place mode.
when_to_use	When beginning work on a tracked issue. Always run before editing files. Replaces ad-hoc `git checkout -b` and hand-rolled `git worktree add`.

kit-task-start

Thin caller over the ONE canonical start mechanic: the cckit start verb → wt_start (${CLAUDE_PLUGIN_ROOT}/scripts/lib/worktree-start.sh). The verb logic lives there, never inline here (kit-engine-boundary #1/#2 — same single-implementation principle as the PR title composer, #121). The verb owns ALL of the mechanics:

• fresh fetch of the base branch (KIT_BASE_BRANCH, default main) + branch <kind>/<N>-<slug> (kind derived from the issue's kind: label)
• the isolated worktree at .claude/worktrees/<kind>+<N>-<slug> (reused if it already exists; the dir name encodes issue #N so kit-gc won't wipe it while the issue is open)
• bootstrap (wt_bootstrap): copies gitignored .env.local* + project ids into the worktree, assigns a per-worktree dev PORT, installs deps (KIT_WT_INSTALL=0 opts out)
• the claim precheck (#124): warns when the issue is already In Progress on the board — another session may own it
• the live-session collision guard: never disturbs a worktree a live session is sitting in
• the board update: issue → In Progress (when Projects v2 is enabled)

Inputs

Field	Required	Notes
Issue number	✓	123
Slug	optional	Short kebab suffix; defaults to a slug of the issue title

Worktree-first, always. Every start gets its own isolated worktree — one branch per worktree, never a shared checkout. This is what makes parallel / sub-agent work safe and keeps a read-only base checkout untouched.

Execution

cckit start <N>            # or: cckit start <N> <slug-override>
# cckit not on PATH? "${CLAUDE_PLUGIN_ROOT}/bin/cckit" start <N>

The last stdout line is machine-readable — <worktree-path>|<branch>|<issue-number> — then work continues inside the worktree:

cd <worktree-path>         # one branch per worktree; never edit the main checkout

Output

• Worktree path + <kind>/<N>-<slug> branch (from the base branch) — work happens in the worktree
• Issue #N In Progress on the board (when Projects v2 is on)

Rules

• Engine boundary — the start mechanic lives in wt_start; this skill only runs the verb. Never re-implement git worktree add / git checkout -B / bootstrap / board steps here.
• Worktree-first: parallel / sub-agent work MUST each get their own worktree via the verb — never share a checkout, never fall back to an in-place branch switch.
• Never start from a non-base branch (trunk-based) — the verb always branches from a fresh origin/<base>.
• If the issue has no role: label, fail loudly and ask for triage before starting.
• Heed the claim-precheck warning: if the verb reports the issue is already In Progress, confirm no other session owns it before continuing.