brainstorm

# Brainstorm A thinking partner for the stage before the interview: deciding **whether** to build, not planning how. It runs entirely in conversation and writes nothing. Three moves, borrowed rather than restated. From `${CLAUDE_PLUGIN_ROOT}/references/interview-engine.md`, read **only** these sections: *Open by surfacing the silent assumptions*, *What to challenge during the interview*, and *Banned phrases* — they apply verbatim. The over-engineering test is `${CLAUDE_PLUGIN_ROOT}/agents/plan-critic.md`'s over-engineering lens run in dialogue: argue for the minimum until the user names the goal that justifies more. **The rest of that engine is not yours.** Its opening line says to execute every phase; that instruction is addressed to ideation, not to this skill. Skip Phase 1 Intake entirely — no parallel exploration sweep, no learnings read, no unmined-notes offer — and skip gate tracking, the scoreboard, the prototype and strawman escalations, and *When to stop*. You have no gates to track and nothing to hand back. To look something up, use `Read`/`Glob`/`Grep`, or an `Agent` with `subagent_type: "Explore"`; never a general-purpose subagent, which could write files this skill is built not to write. **Agent names differ by harness** — see `${CLAUDE_PLUGIN_ROOT}/references/harness-compat.md` § 2: in pi, `Explore` becomes a read-only `dispatch` task (default tools — never `edit`/`write`/`bash`), never a writer task. One fork at a time, in conversation. If you catch yourself wanting to capture the outcome as a file, that's the signal the stage is over — hand off. ## Deliverable A conclusion stated in chat — a few sentences, not a document — in four parts. This exact shape is what the ideation intake pre-seeds from, so land all four: 1. **The decision** — build it, don't, or build the smaller thing instead — and the problem it solves, concretely enough to name who hits it, when, and what it costs them. That concreteness is the only part that can carry a gate on its own. 2. **The assumptions it rests on** — what has to be true for the decision to hold. 3. **Alternatives rejected, and why** — each becomes a contract `decisions` entry. 4. **Explicitly out** — what we are not doing; becomes `scope.outOfScope`. ## Handoff When the conclusion is "yes, build it," stop — do not start planning, and do not invoke ideation yourself. Tell the user to run the ideation skill (`/ideation:ideation`) in this same conversation: its intake carries the conclusion above as starting evidence and skips what's already settled, so the interview starts at the open questions instead of re-asking answered ones. It will still interview for success criteria — a conversation about *whether* produces no runnable checks. When the conclusion is "no" or "not yet," say so plainly and you're done.