---
name: ce-brainstorm
description: 'Explore requirements and approaches through collaborative dialogue before writing a right-sized requirements document and planning implementation. Use for feature ideas, problem framing, when the user says ''let''s brainstorm'', or when they want to think through options before deciding what to build. Also use when a user describes a vague or ambitious feature request, asks ''what should we build'', ''help me think through X'', presents a problem with multiple valid solutions, or seems unsure about scope or direction — even if they don''t explicitly ask to brainstorm.'
argument-hint: "[feature idea or problem to explore]"
---

# Brainstorm a Feature or Improvement

**Note: The current year is 2026.** Use this when dating requirements documents.

Brainstorming helps answer **WHAT** to build through collaborative dialogue. It precedes `/ce-plan`, which answers **HOW** to build it.

The durable output of this workflow is a **requirements document**. In other workflows this might be called a lightweight PRD or feature brief. In compound engineering, keep the workflow name `brainstorm`, but make the written artifact strong enough that planning does not need to invent product behavior, scope boundaries, or success criteria.

This skill does not implement code. It explores, clarifies, and documents decisions for later planning or execution.

**IMPORTANT: All file references in generated documents must use repo-relative paths (e.g., `src/models/user.rb`), never absolute paths. Absolute paths break portability across machines, worktrees, and teammates.**

## Core Principles

1. **Assess scope first** - Match the amount of ceremony to the size and ambiguity of the work.
2. **Be a thinking partner** - Suggest alternatives, challenge assumptions, and explore what-ifs instead of only extracting requirements.
3. **Resolve product decisions here** - User-facing behavior, scope boundaries, and success criteria belong in this workflow. Detailed implementation belongs in planning.
4. **Keep implementation out of the requirements doc by default** - Do not include libraries, schemas, endpoints, file layouts, or code-level design unless the brainstorm itself is inherently about a technical or architectural change.
5. **Right-size the artifact** - Simple work gets a compact requirements document or brief alignment. Larger work gets a fuller document. Do not add ceremony that does not help planning.
6. **Apply YAGNI to carrying cost, not coding effort** - Prefer the simplest approach that delivers meaningful value. Avoid speculative complexity and hypothetical future-proofing, but low-cost polish or delight is worth including when its ongoing cost is small and easy to maintain.

## Interaction Rules

1. **Ask one question at a time** - Do not batch several unrelated questions into one message.
2. **Prefer single-select multiple choice** - Use single-select when choosing one direction, one priority, or one next step.
3. **Use multi-select rarely and intentionally** - Use it only for compatible sets such as goals, constraints, non-goals, or success criteria that can all coexist. If prioritization matters, follow up by asking which selected item is primary.
4. **Use the platform's blocking question tool** - `AskUserQuestion` in Claude Code (call `ToolSearch` with `select:AskUserQuestion` first if its schema isn't loaded), `request_user_input` in Codex, `ask_user` in Gemini. Fall back to numbered options in chat only when no blocking tool exists in the harness or the call errors (e.g., Codex edit modes) — not because a schema load is required. Never silently skip the question.

## Output Guidance

- **Keep outputs concise** - Prefer short sections, brief bullets, and only enough detail to support the next decision.
- **Use repo-relative paths** - When referencing files, use paths relative to the repo root (e.g., `src/models/user.rb`), never absolute paths. Absolute paths make documents non-portable across machines and teammates.

## Feature Description

<feature_description> #$ARGUMENTS </feature_description>

**If the feature description above is empty, ask the user:** "What would you like to explore? Please describe the feature, problem, or improvement you're thinking about."

Do not proceed until you have a feature description from the user.

## Execution Flow

### Phase 0: Resume, Assess, and Route

#### 0.1 Resume Existing Work When Appropriate

If the user references an existing brainstorm topic or document, or there is an obvious recent matching `*-requirements.md` file in `docs/brainstorms/`:
- Read the document
- Confirm with the user before resuming: "Found an existing requirements doc for [topic]. Should I continue from this, or start fresh?"
- If resuming, summarize the current state briefly, continue from its existing decisions and outstanding questions, and update the existing document instead of creating a duplicate

#### 0.1b Classify Task Domain

Before proceeding to Phase 0.2, classify whether this is a software task. The key question is: **does the task involve building, modifying, or architecting software?** -- not whether the task *mentions* software topics.

**Software** (continue to Phase 0.2) -- the task references code, repositories, APIs, databases, or asks to build/modify/debug/deploy software.

**Non-software brainstorming** (route to universal brainstorming) -- BOTH conditions must be true:
- None of the software signals above are present
- The task describes something the user wants to explore, decide, or think through in a non-software domain

**Neither** (respond directly, skip all brainstorming phases) -- the input is a quick-help request, error message, factual question, or single-step task that doesn't need a brainstorm.

**If non-software brainstorming is detected:** Read `references/universal-brainstorming.md` and use those facilitation principles to brainstorm with the user naturally. Do not follow the software brainstorming phases below.

#### 0.2 Assess Whether Brainstorming Is Needed

**Clear requirements indicators:**
- Specific acceptance criteria provided
- Referenced existing patterns to follow
- Described exact expected behavior
- Constrained, well-defined scope

**If requirements are already clear:**
Keep the interaction brief. Confirm understanding and present concise next-step options rather than forcing a long brainstorm. Only write a short requirements document when a durable handoff to planning or later review would be valuable. Skip Phase 1.1 and 1.2 entirely — go straight to Phase 1.3 or Phase 3.

#### 0.3 Assess Scope

Use the feature description plus a light repo scan to classify the work:
- **Lightweight** - small, well-bounded, low ambiguity
- **Standard** - normal feature or bounded refactor with some decisions to make
- **Deep** - cross-cutting, strategic, or highly ambiguous

If the scope is unclear, ask one targeted question to disambiguate and then proceed.

**Deep sub-mode: feature vs product.** For Deep scope, also classify whether the brainstorm must establish product shape or inherit it:

- **Deep — feature** (default): existing product shape anchors decisions. Primary actors, core outcome, positioning, and primary flows are already established in the product or repo. The brainstorm extends or refines within that shape.
- **Deep — product**: the brainstorm must establish product shape rather than inherit it. Primary actors, core outcome, positioning against adjacent products, or primary end-to-end flows are materially unresolved. Existing code lowers the odds of product-tier but does not by itself rule it out — a half-built tool with ambiguous shape is still product-tier.

Product-tier triggers additional Phase 1.2 questions and additional sections in the requirements document. Feature-tier uses the current Deep behavior unchanged.

### Phase 1: Understand the Idea

#### 1.1 Existing Context Scan

Scan the repo before substantive brainstorming. Match depth to scope:

**Lightweight** — Search for the topic, check if something similar already exists, and move on.

**Standard and Deep** — Two passes:

*Constraint Check* — Check project instruction files (`AGENTS.md`, and `CLAUDE.md` only if retained as compatibility context) for workflow, product, or scope constraints that affect the brainstorm. If these add nothing, move on.

*Topic Scan* — Search for relevant terms. Read the most relevant existing artifact if one exists (brainstorm, plan, spec, skill, feature doc). Skim adjacent examples covering similar behavior.

If nothing obvious appears after a short scan, say so and continue. Two rules govern technical depth during the scan:

1. **Verify before claiming** — When the brainstorm touches checkable infrastructure (database tables, routes, config files, dependencies, model definitions), read the relevant source files to confirm what actually exists. Any claim that something is absent — a missing table, an endpoint that doesn't exist, a dependency not in the Gemfile, a config option with no current support — must be verified against the codebase first; if not verified, label it as an unverified assumption. This applies to every brainstorm regardless of topic.

2. **Defer design decisions to planning** — Implementation details like schemas, migration strategies, endpoint structure, or deployment topology belong in planning, not here — unless the brainstorm is itself about a technical or architectural decision, in which case those details are the subject of the brainstorm and should be explored.

**Slack context** (opt-in, Standard and Deep only) — never auto-dispatch. Route by condition:

- **Tools available + user asked**: Dispatch `ce-slack-researcher` with a brief summary of the brainstorm topic alongside Phase 1.1 work. Incorporate findings into constraint and context awareness.
- **Tools available + user didn't ask**: Note in output: "Slack tools detected. Ask me to search Slack for organizational context at any point, or include it in your next prompt."
- **No tools + user asked**: Note in output: "Slack context was requested but no Slack tools are available. Install and authenticate the Slack plugin to enable organizational context search."

#### 1.2 Product Pressure Test

Before generating approaches, challenge the request to catch misframing. Match depth to scope:

**Lightweight:**
- Is this solving the real user problem?
- Are we duplicating something that already covers this?
- Is there a clearly better framing with near-zero extra cost?

**Standard:**
- Is this the right problem, or a proxy for a more important one?
- What user or business outcome actually matters here?
- What happens if we do nothing?
- Is there a nearby framing that creates more user value without more carrying cost? If so, what complexity does it add?
- Given the current project state, user goal, and constraints, what is the single highest-leverage move right now: the request as framed, a reframing, one adjacent addition, a simplification, or doing nothing?
- Favor moves that compound value, reduce future carrying cost, or make the product meaningfully more useful or compelling
- Use the result to sharpen the conversation, not to bulldoze the user's intent

**Deep** — Standard questions plus:
- What durable capability should this create in 6-12 months?
- Does this move the product toward that, or is it only a local patch?

**Deep — product** — Deep questions plus:
- What's the single sharpest user outcome this earns, and what evidence or assumption supports that outcome?
- What adjacent product could we accidentally build instead, and why is that the wrong one?
- What would have to be true in the world for this to fail?

These questions force an explicit product thesis and feed the Scope Boundaries subsections ("Deferred for later" and "Outside this product's identity") and Dependencies / Assumptions in the requirements document.

#### 1.3 Collaborative Dialogue

Follow the Interaction Rules above. Use the platform's blocking question tool when available.

**Guidelines:**
- Ask what the user is already thinking before offering your own ideas. This surfaces hidden context and prevents fixation on AI-generated framings.
- Start broad (problem, users, value) then narrow (constraints, exclusions, edge cases)
- Clarify the problem frame, validate assumptions, and ask about success criteria
- Make requirements concrete enough that planning will not need to invent behavior
- Surface dependencies or prerequisites only when they materially affect scope
- Resolve product decisions here; leave technical implementation choices for planning
- Bring ideas, alternatives, and challenges instead of only interviewing

**Exit condition:** Continue until the idea is clear OR the user explicitly wants to proceed.

### Phase 2: Explore Approaches

If multiple plausible directions remain, propose **2-3 concrete approaches** based on research and conversation. Otherwise state the recommended direction directly.

Use at least one non-obvious angle — inversion (what if we did the opposite?), constraint removal (what if X weren't a limitation?), or analogy from how another domain solves this. The first approaches that come to mind are usually variations on the same axis.

Present approaches first, then evaluate. Let the user see all options before hearing which one is recommended — leading with a recommendation before the user has seen alternatives anchors the conversation prematurely.

When useful, include one deliberately higher-upside alternative:
- Identify what adjacent addition or reframing would most increase usefulness, compounding value, or durability without disproportionate carrying cost. Present it as a challenger option alongside the baseline, not as the default. Omit it when the work is already obviously over-scoped or the baseline request is clearly the right move.

At product tier, alternatives should differ on *what* is built (product shape, actor set, positioning), not *how* it is built. Implementation-variant alternatives belong at feature tier.

For each approach, provide:
- Brief description (2-3 sentences)
- Pros and cons
- Key risks or unknowns
- When it's best suited

After presenting all approaches, state your recommendation and explain why. Prefer simpler solutions when added complexity creates real carrying cost, but do not reject low-cost, high-value polish just because it is not strictly necessary.

If one approach is clearly best and alternatives are not meaningful, skip the menu and state the recommendation directly.

If relevant, call out whether the choice is:
- Reuse an existing pattern
- Extend an existing capability
- Build something net new

### Phase 3: Capture the Requirements

Write or update a requirements document only when the conversation produced durable decisions worth preserving. Read `references/requirements-capture.md` for the document template, formatting rules, visual aid guidance, and completeness checks.

For **Lightweight** brainstorms, keep the document compact. Skip document creation when the user only needs brief alignment and no durable decisions need to be preserved.
### Phase 3.5: Document Review

When a requirements document was created or updated, run the `ce-doc-review` skill on it before presenting handoff options. Pass the document path as the argument.

If document-review returns findings that were auto-applied, note them briefly when presenting handoff options. If residual P0/P1 findings were surfaced, mention them so the user can decide whether to address them before proceeding.

When document-review returns "Review complete", proceed to Phase 4.

### Phase 4: Handoff

Present next-step options and execute the user's selection. Read `references/handoff.md` for the option logic, dispatch instructions, and closing summary format.
