Example

A falling-block puzzle built with just 2 prompts

Two inputs: "write the spec" → "implement the spec."
The result: a falling-block puzzle game with chain reactions and game-over detection.
Model used: Gemini 3.8 Flash. The API cost was roughly $0.10 (about ¥14, confirmed in Google AI Studio).

Play the game Back to product page

The finished falling-block puzzle mid-game, showing a score of 460 and a max chain of 3

What we did

Selected Gemini 3.8 Flash and created an empty folder via "New Project"
Prompt 1: "First, create only a readme.md summarizing the spec" → the AI generated the spec document
Prompt 2: "Implement it according to the spec in readme.md" → the AI created index.html / style.css / script.js (file writes confirmed via the approval dialog)
Ran start index.html in the built-in terminal → the game ran in the browser

Instead of asking for code right away, we used a two-stage prompt: have the AI generate the spec (readme.md) first, then implement it. The spec becomes a human review point, and the implementation request is just "do it per the spec" — the same flow as real-world work, which makes the result far more reliable.

1. Pick a model, create a new project

We confirmed the AI chat model was set to gemini-3.8-flash, then created an empty folder with "New Project" in the Explorer.

Teaspoon IDE right after launch with the English UI: gemini-3.8-flash is selected as the AI chat model and the New Project button is highlighted — Model: Gemini 3.8 Flash. Start by creating an empty folder with "New Project".

2. Prompt 1 — have it write only the spec

This is what we typed into the chat. The key points: explicitly say "don't implement anything yet — just create readme.md", and leave the undecided details (board size, number of colors) to the AI so they get nailed down in the spec. Also note the last line: in an earlier run without "write everything in English", the replies came back in Japanese — stating the output language explicitly is the reliable fix.

I want to make a simple falling-block puzzle game. Don't implement anything yet — just create a readme.md that summarizes the spec. The spec: stones fall from the top in pairs of two; after they land, any group of 3 or more same-colored stones connected horizontally or vertically disappears; after stones disappear, the stones above fall down, and if they line up again it triggers a chain; if a piece finishes falling while still sticking out above the top of the screen, it's game over. Controls: press 4 to move left, 6 to move right, 5 to rotate clockwise, 2 for fast drop. Use a 3-file structure: index.html, style.css, and script.js. No sound effects — keep it simple. For anything I haven't specified, like board size or number of colors, decide reasonable values yourself and write them into readme.md. Important: write everything in English — the readme.md content and all your chat replies.

The AI-generated readme.md spec in English: file structure, board size, stone colors, and controls itemized, with an English summary shown in the chat pane on the right — The AI-generated spec, `readme.md`. Details we didn't decide — board size, color count — were filled in as part of the spec.

Give the content a quick review here. If anything looks off, either edit readme.md directly or send a follow-up instruction.

3. Prompt 2 — implement per the spec

Once the spec exists, the implementation request is just this:

Implement it according to the spec in readme.md. Reply in English.

The AI reads readme.md and creates the three files per the spec. File writes are previewed in an approval dialog — review the diff, then apply.

The File Edit Approval dialog previewing the new index.html content highlighted in green, showing '2 file(s) to edit' — The "File Edit Approval" dialog — you can review exactly what will be written.

4. Launch from the built-in terminal

Open the terminal via "View → Toggle Terminal" and run start index.html — the game opens in your default browser.

The built-in terminal with 'start index.html' typed into the command input — The built-in terminal runs commands in the project root. Asking the AI to "open it in the browser" works too.

5. The finished game

Move each two-stone pair with 4 and 6, rotate with 5, and fast-drop with 2. Groups of 3 or more matching colors disappear, and the stones above drop to trigger chains. A NEXT preview, score and max-chain counters, an on-screen pad, and a game-over screen with retry were all implemented.

The game right after launch: an empty board with NEXT, SCORE, HIGH SCORE, and MAX CHAIN panels plus a controls guide and an on-screen pad — Right after launch — NEXT, SCORE, MAX CHAIN, a control guide, and an on-screen pad in the side panels.

Mid-game screen: colorful stones stacked on the board, showing a score of 460 and a max chain of 3 — Actual gameplay — chains work as designed.

Play this game in your browser See the AI-generated spec (readme.md)

What this example shows

Real cost: about $0.10 Gemini 3.8 Flash with BYOK (bring your own API key) — a whole game for roughly ¥14. Choose a local LLM via Ollama and the same thing is completely free and offline.
The spec-first, two-stage prompt works Having readme.md written first is more stable than asking for code right away. The spec is a document humans can review and adjust, and the implementation request boils down to "per the spec".
Safe by approval File writes, edits, and command execution all require approval — the AI never proceeds on its own.
No jargon required "Create a readme.md summarizing the spec" and "implement per the spec" — the IDE interprets the internal file-creation commands (WRITE_FILE and friends), so plain English is all you need.

* The UI in the screenshots uses the "Coquette" theme. See the other themes in the theme gallery.

Try it yourself

Teaspoon IDE is free to download. All you need is a Gemini API key (free tier available) or a local LLM via Ollama.

Download Settings guide Example 1 (Othello)