Collaborative Brainstorming

Structured ideation using the Double Diamond model, grounded in persistent memory. Mined from 100+ real brainstorming sessions across production projects.

Core insight: AI excels at divergent phases (volume, cross-domain connections). Humans excel at convergent phases (judgment, selection). This skill separates the two and uses Sibyl as institutional memory to prevent re-exploring solved problems.

The Process

digraph brainstorm {
    rankdir=TB;
    node [shape=box];

    "1. GROUND" [style=filled, fillcolor="#e8e8ff"];
    "2. DIVERGE: Problem" [style=filled, fillcolor="#ffe8e8"];
    "3. CONVERGE: Define" [style=filled, fillcolor="#e8ffe8"];
    "4. DIVERGE: Solutions" [style=filled, fillcolor="#ffe8e8"];
    "5. CONVERGE: Decide" [style=filled, fillcolor="#e8ffe8"];
    "EXIT → Any skill" [style=filled, fillcolor="#fff8e0"];

    "1. GROUND" -> "2. DIVERGE: Problem";
    "2. DIVERGE: Problem" -> "3. CONVERGE: Define";
    "3. CONVERGE: Define" -> "4. DIVERGE: Solutions";
    "4. DIVERGE: Solutions" -> "5. CONVERGE: Decide";
    "5. CONVERGE: Decide" -> "EXIT → Any skill";
}

Phase 1: GROUND (Memory-First)

Before generating a single idea, search what we already know.

Actions

1. Search Sibyl for related patterns, past decisions, known constraints:

   • sibyl search "<topic keywords>" — find prior art
   • sibyl search "<related architecture>" — find relevant patterns
   • Check for existing tasks/epics on this topic

2. Surface constraints — what’s already decided? What’s non-negotiable?

   • Tech stack locked? Budget constraints? Timeline?
   • Existing patterns we must follow?

3. Present prior art — show the user what Sibyl knows before ideating:

   “Sibyl has 3 relevant entries: [pattern X from project Y], [decision Z from last month], [gotcha W]. Want to factor these in?”

Gate

If Sibyl has a directly applicable pattern or decision, present it first. Don’t re-brainstorm solved problems.

Phase 2: DIVERGE — Explore the Problem Space

Goal: Generate breadth. Understand what we’re actually solving.

Actions

1. Ask ONE question at a time to understand intent:

   • What’s the friction/pain point?
   • Who benefits? How do they use it today?
   • What does success look like?

2. Reframe the problem from multiple angles:

   • User perspective: “As a [user], I need…”
   • System perspective: “The system currently…”
   • Constraint perspective: “We’re bounded by…”

3. If the problem space is large, spawn parallel Explore agents:

   Agent 1: Research how similar projects solve this
   Agent 2: Map the existing codebase surface area
   Agent 3: Search for SOTA approaches (WebSearch)
   

Anti-patterns

• Don’t jump to solutions. This phase is about the PROBLEM.
• Don’t ask 5 questions at once. One at a time, build understanding.
• Don’t dismiss vague input — “make it faster” is valid; help sharpen it.

Phase 3: CONVERGE — Define the Core Problem

Goal: Narrow from exploration to a crisp problem statement.

Actions

1. Synthesize what was explored into a 1-2 sentence problem statement
2. Confirm with the user: “Is this what we’re solving?”
3. Identify scope boundaries — what’s IN, what’s OUT

Output

Problem: [crisp statement] In scope: [what we’ll address] Out of scope: [what we won’t] Key constraint: [the most important limiting factor]

Phase 4: DIVERGE — Explore Solutions

Goal: Generate multiple viable approaches. Quality through quantity.

Actions

1. Present 2-3 approaches with explicit tradeoffs:

   Approach	Pros	Cons	Complexity	Risk
   A: [name]	…	…	Low/Med/High	…
   B: [name]	…	…	Low/Med/High	…
   C: [name]	…	…	Low/Med/High	…

2. Include at least one unconventional option — break fixation on the obvious path

3. Ground in existing patterns:

   • “This follows the pattern we used in [project X]”
   • “This diverges from our convention because [reason]”

4. For each approach, name the verification method:

   • How would we know it works? (Test? Benchmark? Visual check?)

Exploration vs Exploitation

Balance like MCTS — don’t fixate on the first decent idea:

• If all approaches look similar → push for a wild card option
• If approaches are wildly different → good, that’s healthy divergence
• If the user gravitates early → present the contrarian case before converging

Anti-patterns

• Don’t present 7 options. 2-3 is the sweet spot.
• Don’t present options without tradeoffs. Every option has a cost.
• Don’t present options that violate known constraints from Phase 1.
• Don’t default to the most complex solution. Start simple, add complexity only if justified.

Phase 5: CONVERGE — Decide and Record

Goal: Lock in the approach. Record the decision. Exit to action.

Actions

1. Let the user choose. Present your recommendation but don’t bulldoze.

2. Record the decision in Sibyl:

   sibyl add "Brainstorm: [topic]" "Chose [approach] because [reason]. Rejected [other approaches] due to [tradeoffs]. Key constraint: [X]."
   

3. Define next action — the brainstorm exits to whatever makes sense:

   Next Step	When
   /hyperskills:plan	Complex feature needing decomposition
   /hyperskills:research	Need deeper investigation first
   /hyperskills:orchestrate	Ready to dispatch agents
   Direct implementation	Simple enough to just build
   Write a spec	Needs formal documentation

Output

Decision: [what we’re doing] Approach: [which option, brief description] Why: [1-2 sentences on the reasoning] Next: [the immediate next action]

Quick Mode

For small decisions that don’t need the full diamond:

1. Search Sibyl (always)
2. Present 2 options with tradeoffs (skip problem exploration)
3. Decide and record

Use quick mode when: The problem is already well-understood and the user just needs help choosing between known options.

Multi-Agent Brainstorming

For complex architectural decisions, deploy a Council pattern:

Agent 1 (Advocate): Makes the strongest case FOR approach A
Agent 2 (Advocate): Makes the strongest case FOR approach B
Agent 3 (Critic): Finds flaws in BOTH approaches

Synthesize their outputs, then present the unified analysis to the user.

When to use: Architecture decisions affecting 3+ systems, technology selection, major refactors. Don’t use for simple feature design.

What This Skill is NOT

• Not a gate. You don’t need permission to skip phases. If the user says “just build it,” build it.
• Not a waterfall. Phases can revisit. New information in Phase 4 can send you back to Phase 2.
• Not a document generator. The output is a decision, not a design doc (unless the user wants one).
• Not required for everything. Bug fixes, typo corrections, and clear-spec features don’t need brainstorming.

YAGNI Check

Before concluding, ask: “Is there anything in this plan we don’t actually need yet?” Strip it. Build the minimum that validates the approach.