$ca-feature — spec-driven feature

The single permitted entry to implementation work. No feature code is written before a spec is approved and tdd Phase 1 clears. A one-line idea is not a spec — brainstorming makes it one.

Orientation: if .codearbiter/code-map.md is present, read it first — a coarse concern→path→role map that orients task authoring. Absent is fine; it is read-on-demand, populated by context-creation or commit-gate heal.

Resume — an interrupted pipeline is re-entered, never restarted

Before triage, scan <project-root>/.codearbiter/specs/ and plans/ for an existing slug matching $ARGUMENTS (invoked bare, list every resumable pipeline and ask which). A crash, compaction, or closed session mid-pipeline loses nothing — the spec, the plan, and each task's status cell are on disk. On a match, confirm the resume with the user in one line ("resume <slug> at ?") and re-enter at the furthest checkpoint reached:

1. Plan exists with non-ACCEPTED tasks → executing-plans (its Phase 1 batches only the remaining tasks).
2. Plan exists, every task ACCEPTED → commit-gate (the work is done and verified; it was the commit that never happened).
3. Spec approved, no plan → writing-plans (routines/writing-plans/SKILL.md).
4. Spec exists but never approved → brainstorming (routines/brainstorming/SKILL.md), at its approval gate — not from scratch.

Re-running brainstorming against an already-approved spec is the failure mode this section exists to prevent: it discards approved decisions and re-asks answered questions. Only an explicit user request ("start over") restarts an existing slug — and that is logged to triage.log like any classification.

Step 0 — change-class triage (logged)

Before routing, classify the request. The small lane applies only when ALL of these hold — judged against $ARGUMENTS and a quick look at the code, never assumed:

• the change touches ≤ 2 implementation files (plus their tests);
• no §4 reference-map scope-touch: auth/crypto/secrets, dependencies, migrations/schema, telemetry, public API surface, domain vocabulary;
• no new dependency, endpoint, command, or configuration surface;
• the behavior change is expressible as 1–3 concrete, individually testable acceptance criteria.

Small lane: state the mini-spec inline (the 1–3 criteria) and STOP for the user's one-reply confirmation. On confirmation, append one line to <project-root>/.codearbiter/triage.log (append-only, >>):

[ISO-8601 timestamp] | BY: <git user.email> | LANE: small | SCOPE: <one-line> | BASIS: <criteria met>

Then route directly to tdd (routines/tdd/SKILL.md) — the confirmed criteria are its Phase 1 obligations; Phases 2–6 run unchanged — and exit through the full commit-gate and finishing-a-development-branch exactly as the full lane does. The lane trims ceremony, never gates.

Any criterion violated, or uncertain → full lane (below). Uncertainty is full-lane; the triage never guesses.

Flow — full lane

Route through the pipeline in order; each step gates the next:

1. brainstorming (routines/brainstorming/SKILL.md) — refine $ARGUMENTS into a concrete spec by Socratic questioning: challenge vague language, surface hidden complexity, force trade-offs. Writes the spec to <project-root>/.codearbiter/specs/<slug>.md. Hard gate: no plan and no code until the user approves the spec. Genuinely-unresolved unknowns become [CONFIRM-NN] in open-questions.md, never guesses.
2. writing-plans (routines/writing-plans/SKILL.md) — decompose the approved spec into small tasks, each with an exact path and a verification that maps to a tdd obligation (it does not replace one). Writes <project-root>/.codearbiter/plans/<slug>.md with bijective criterion↔task coverage.
3. executing-plans (routines/executing-plans/SKILL.md) — coordinates the plan in small batches with human checkpoints. Each batch is delegated to subagent-driven-development (routines/subagent-driven-development/SKILL.md — fresh author agent per task, spec-compliance review, quality review, fresh verification). The user acknowledges between batches; nothing advances until they do.
4. commit-gate — the only path to a commit; nine gates, including behavioral proof.
5. finishing-a-development-branch — terminal step: open-PR / merge-via-PR / discard. Every change lands through a PR; never a direct write to the default branch.

The autonomous counterpart ($ca-sprint) runs the same spec→plan but passes the full plan to subagent-driven-development directly, without per-batch checkpoints. That path is its own entry, not /feature.

Scope routing

Scope determines which author agent subagent-driven-development dispatches per task: backend-author, frontend-author, or infra-author — per the mapping in tech-stack.md. A multi-area feature runs the appropriate agent per task; the full suite must be green before transitioning between scope areas.

When NOT to use

• A known defect with a reproduction → /fix.
• A behavior-preserving restructure → /refactor.
• A question or quick discussion → /btw.
• Persisting work already written → /commit.

Hard gate

MUST NOT write feature code before a spec is approved AND tdd Phase 1 clears — the brainstormed spec in the full lane, the user-confirmed mini-spec in the small lane. MUST NOT take the small lane unless every Step 0 criterion holds, and MUST log the classification to .codearbiter/triage.log before tdd begins. MUST NOT skip writing-plans in the full lane. MUST NOT resolve a [CONFIRM-NN] in the spec by guessing — surface it. MUST NOT restart an interrupted pipeline whose artifacts exist on disk — resume at the furthest checkpoint per the Resume ladder, unless the user explicitly asks to start over.