# How to Brainstorm and Kill App Ideas With AI in an Afternoon

> A structured way to brainstorm product ideas with an AI sparring partner: generate widely, attack each idea, keep only the ones worth a first version.

- URL: https://shotmatic.app/blog/brainstorm-app-ideas-with-ai
- Category: Ideas & Brainstorming
- Published: 2026-09-27
- Author: Tu Nguyen

## Key takeaways

- Use AI to widen the field of ideas and to attack them, not to tell you which idea will succeed.
- Run brainstorming in three rounds: diverge (many ideas), attack (find reasons each fails), converge (pick one first version).
- Kill ideas quickly and write down why; a killed idea with a reason is progress.
- An idea is ready for an agent when you can write one paragraph: who, which problem, what 'done' means for v0.1.

The cost of building a first version has collapsed. An agent can scaffold an app in an afternoon. That
makes the **choice of idea** the expensive decision — you can now waste a month on the wrong thing much
faster than before.

This post is a three-round brainstorming method that uses AI as a sparring partner. It fits before step 1 of
[the AI agent workflow](https://shotmatic.app/blog/ai-agent-project-workflow).

## Round 1 — Diverge: get past the obvious

Start from something real: a problem you had this week, a workflow that annoyed you, a community you know
well. Then ask the AI to widen it:

```text
I keep losing track of which side project is stuck. List 25 product ideas around this problem,
one line each, for different kinds of people (developers, writers, students, small shops).
Include some odd ones.
```

Add your own ideas to the list. Don't judge yet. The first ten ideas are usually the obvious ones everybody
has; the interesting ones come after.

## Round 2 — Attack: find the reasons each idea fails

Pick the five ideas you find most interesting and ask the AI to argue against them:

```text
For each idea, give the three strongest reasons it would fail as a paid product for a solo developer.
Be specific: existing tools, who would not pay, what is hard to build or to explain.
```

This is where AI is most useful — it is tireless at finding objections and has no attachment to your
ideas. Your job is to judge which objections are real. Some are fatal (*"everyone already gets this free
inside their editor"*); some just tell you what the first version must prove.

## Round 3 — Converge: one paragraph and a won't-do list

Choose one idea and write the paragraph by hand:

> **For** solo developers running several repos with AI agents, **who** lose track of status and sessions,
> **v0.1 is done when** they can see every repo's current task on one screen and resume its session in one
> click.

If you can't write that paragraph, go back to round 2. If you can, write the first
[won't-do list](https://shotmatic.app/blog/wont-do-list-scope-creep) immediately, while you still remember which features you
were tempted by.

## Kill ideas fast — and write down why

Most ideas should die in round 2. That is the method working. Keep an `ideas.md` with every killed idea and
its one-line reason:

```markdown
- Habit tracker for developers — killed 2026-09: crowded, no reason to switch.
- Session search for Claude — parked: interesting, but part of a bigger problem (status across repos).
```

"Parked" ideas are often the seeds of better ones: the reason for "not now" can stop being true.

## What AI can't do for you

- **It can't measure demand.** It knows what has been written, not what people will pay for next month.
- **It can't know your advantage.** Which idea you are unusually well placed to build is your call.
- **It won't tell you to stop.** Ask it to find reasons an idea fails; don't ask whether it is good.

After converging, test with people: a landing page, a post in a community you belong to, or a
[small launch](https://shotmatic.app/blog/indie-marketing-many-small-products).

## Where ShotMatic fits

Brainstorming produces more projects than you can run, and that is fine — as long as each one has a phase
and a next step you can see. Put ideas that survive round 3 on a board in the Backlog tab; they stay visible
without competing with the work that is active.

## FAQ

**Can AI tell me if my app idea is good?**

Not reliably. It can list competitors it knows about, find weaknesses in your reasoning and suggest who might want the product, but it cannot know real demand. Use it to sharpen the idea, then test with real people.

**How many ideas should I generate before choosing?**

Enough that the first obvious ones are behind you — often 20 to 30 quick one-liners. The good ideas tend to come after the obvious ones are written down.

**What should I do with ideas I don't pick?**

Keep them in an ideas file with the reason you didn't pick them now. Many good products are old ideas whose reason for 'not now' stopped being true.