Devil's advocate cofounder that challenges your startup ideas
npx claudepluginhub patchflux/brainstormerDevil's advocate cofounder - challenges ideas through research and clarification until crystal clear or killed early
Devil's advocate cofounder bot for Claude.
Challenges your ideas through dichotomy questioning until they're crystal clear — or kills them early.
Not a yes-person. Not an interviewer. A skeptical cofounder who'd rather save you months of wasted effort.
Most ideas fail because they're vague. "It's for everyone" means no one cares deeply. "We'll figure out monetization later" means you don't have a business.
Brainstomer forces hard choices through binary questions until:
Inspired by GSD — same philosophy of thin orchestrators, parallel agents, and goal-backward thinking.
/plugin marketplace add patchflux/brainstormer
/plugin install brainstomer@brainstomer
Or add directly:
/plugin add patchflux/brainstormer
curl -fsSL https://raw.githubusercontent.com/patchflux/brainstomer/main/install.sh | sh
Files are installed to ~/.claude/brainstomer/.
| Command | Description |
|---|---|
/brainstorm:new | Start new session (idea → research → clarify) |
/brainstorm:clarify | Resume clarification session |
/brainstorm:specs | Generate specs (after clarification passes) |
/brainstorm:help | Show usage |
/brainstorm:new
│
▼
┌─────────────┐
│ Capture │ "What's the idea?"
│ Raw Idea │
└─────────────┘
│
▼
┌─────────────┐
│ Research │ 4 parallel agents investigate:
│ (parallel) │ Market, Competitors, Willingness, Timing
└─────────────┘
│
▼
┌─────────────┐
│ Clarify │ Dichotomy questions until clarity
│ (loop) │ or kill signal
└─────────────┘
│
├── Clarity achieved → /brainstorm:specs
├── Pivot recommended → /brainstorm:new with new angle
└── Kill recommended → Stop (you saved months)
Every question is a choice, not an open prompt.
Bad: "Who is your target user?" Good: "Is this for developers or non-technical users?"
Bad: "What's the main value?" Good: "Does this save time or save money? Pick one."
Forces precision. Reveals priorities. Kills vagueness.
Brainstomer watches for these and names them:
| Signal | What It Means |
|---|---|
| Circular reasoning | Answers keep coming back to unproven assumptions |
| Solution-first | Describing features, not problems |
| Everyone problem | Can't narrow down who has the pain |
| No switching cost | Current solutions work fine |
| Timing vacuum | No reason why now vs any other time |
When a kill signal appears, Brainstomer recommends: pivot, kill, or override.
These mean the idea is sharpening:
| Signal | What It Means |
|---|---|
| Specific person | Can describe target user in detail |
| Felt pain | First-hand experience with the problem |
| Clear villain | Knows exactly what they're replacing |
| Obvious trigger | Knows when someone would seek this out |
| Simple pitch | One sentence explains everything |
All files in .brainstorm/:
.brainstorm/
├── IDEA.md # Raw idea capture
├── research/
│ ├── MARKET.md # Who has this problem
│ ├── COMPETITORS.md # What exists today
│ ├── WILLINGNESS.md # Will they pay
│ ├── TIMING.md # Why now
│ └── SUMMARY.md # Synthesis
├── HISTORY.md # Full Q&A log
├── PRODUCT_SPEC.md # Product spec (after clarity)
└── TECHNICAL_SPEC.md # Technical spec (after clarity)
After specs are generated, feed directly into GSD:
/gsd:new-project --auto @.brainstorm/PRODUCT_SPEC.md
This skips GSD's questioning phase (already done) and goes straight to roadmap creation.
| Agent | Role |
|---|---|
brainstorm-researcher | 4 parallel instances investigate market viability |
brainstorm-clarifier | Devil's advocate questioning loop |
brainstorm-specwriter | Synthesizes specs from validated clarity |
From GSD:
Unique to Brainstomer:
/brainstorm:new
> What's the idea?
"A tool that helps developers write better commit messages"
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BRAINSTOMER ► RESEARCHING
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[4 parallel researchers run...]
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