> ## Documentation Index > Fetch the complete documentation index at: https://docs.summerengine.com/llms.txt > Use this file to discover all available pages before exploring further. # Brainstorm game skill for AI agents > Turn a vague game idea into a 1-page brief (genre, scope, core loop, mechanics) in .summer/GameSoul.md. A Summer Engine skill for AI agents. `brainstorm-game` is a skill from the [Summer skill library](/mcp/skills): a guide your AI agent reads when the task matches, so it builds the good version on the first try. Turn a vague game idea into a 1-page brief (genre, scope, core loop, mechanics) in .summer/GameSoul.md. | | | | - | - | | Status | Stable | | Domains | Scenes and project, Project | | Version | `1.0.3` | | Engine version | `>=4.6` | | Recommended set | Yes, installed by `--recommended` | ## When your agent uses it * The user wants help deciding what game to make, scoping a new project, or turning a vague idea into a buildable plan * The user has a genre, theme, or one-line pitch but no core loop, scope, or brief yet ## Install `summer setup` installs every skill for your agent. To add only this one: ```bash theme={null} npx -y summer-engine@latest skills install brainstorm-game --agent claude-code ``` Swap `claude-code` for your agent, such as `codex` or `cursor`. See [Skills](/mcp/skills#quick-start) for every option. ## The skill ## Overview Most game projects fail because they were never scoped. This skill turns "I want to make a game" into a 1-page brief that names the pitch, the core loop, three mechanics max, the art direction, and the scope (jam / vertical slice / full game). The brief lands at `.summer/GameSoul.md` — the file Summer's onboarding pipeline and every future Summer skill reads on first turn. **Core principle:** Constrain ruthlessly. A buildable bad idea beats an un-buildable great idea. Three mechanics, one art direction, one scope. Anything else gets parked in a "Later" list. ## Steps ### 1. Open with the one question Ask exactly this and wait: > One sentence — what kind of game do you want to make? Don't pre-pitch genres. Don't list options. Read what they say. The first sentence is signal. If they freeze ("I don't know"), offer 4 reference points only: > No worries. Pick the one that pulls you most: a) something cozy and exploratory (Stardew, A Short Hike), b) something tight and skill-based (Celeste, Hades), c) something story-led (Disco Elysium, Citizen Sleeper), d) something silly and short (Goat Sim, Untitled Goose). Or describe a different vibe. ### 2. Branch on genre signal Read their answer for a genre anchor and pick **one** branch. Don't ask multiple questions in parallel. | Anchor word(s) | Branch | | - | - | | "shooter", "FPS", "TPS", "combat" | Action-Combat branch | | "platformer", "metroidvania", "souls-like" | Skill-Platforming branch | | "RPG", "story", "narrative", "dialogue" | Narrative branch | | "roguelike", "deckbuilder", "auto-battler" | Run-Based branch | | "sim", "cozy", "farming", "city-builder" | Sim branch | | "puzzle", "physics", "sandbox" | Puzzle branch | | "horror", "atmospheric" | Horror branch | | "multiplayer", "PvP", "co-op" | Multiplayer branch (forces the multiplayer-or-not call before scope) | If unclear, ask the smallest disambiguating question: > Tighter on this — is it more "tense and dangerous" or "calm and exploratory"? ### 3. Pin the core loop A core loop is what the player does for 30 seconds, repeated. State a candidate and ask them to refine. Examples per branch: | Branch | Candidate core loop | | - | - | | Action-Combat | "Enter room, read enemy patterns, kill, loot, advance." | | Skill-Platforming | "See obstacle, attempt, fail, learn, retry, clear, next." | | Narrative | "Walk to character, choose dialogue, see consequence, walk to next." | | Run-Based | "Pick a card/weapon/build, fight, die, unlock, repeat with edge." | | Sim | "Plan day, execute, harvest reward, plan next day." | | Puzzle | "See state, form theory, test, observe, solve or rethink." | | Horror | "Hear cue, locate threat, hide or flee, advance space." | State your candidate. Ask: > The 30-second loop I'm hearing: \. Does that match what you have in your head, or is the actual moment-to-moment different? ### 4. Constrain to three mechanics maximum Force the trade. State the rule: > Three mechanics, no more. What are the three things this game has that other games in this genre don't? If they pitch five, push back. Not "we'll add it later" — actually cut. Two examples for them to react to: > Hades has three: dash-attack-cast, room reward choice, and run-end conversation. Everything else (mirror upgrades, weapon variants, bosses) is content built on those three. What are yours? Common new-dev mistake: listing features ("inventory, crafting, quests") instead of mechanics ("a single resource that's both currency and ammo"). Push them toward verbs and decisions, not nouns and systems. ### 5. Pick an art direction in one phrase Not a paragraph. Examples to anchor: * "Lo-fi PS1 polygons + dithered shader" * "Hand-drawn 2D, single bold outline, 4-color palette" * "Toon-shaded Nintendo-bright, no realistic lighting" * "Pixel art, 16x16 tiles, GameBoy 4-shade green" Ask: > One phrase for the look. If a stranger asked your screenshot's style in 6 words, what do you say? Don't go deeper here — `/art-direction` is where the bible gets built. This is one phrase to seed it. ### 6. Pin the scope State the choices flat: > Scope. Pick one: (a) a 4-hour jam-sized prototype — one mechanic, one level, one art direction, ships in a weekend. (b) a vertical slice — 30-60 minutes of polished play that proves the core loop, ships in 2-4 weeks. (c) a full game — 4-20 hours of content, ships in 6+ months. If they flinch at (c), recommend (b). New devs almost always overestimate scope. Default recommendation if they're unsure: **vertical slice**. ### 7. Sanity-check the combination Do this in your head, not out loud unless something fails: * Is the core loop achievable with the three mechanics + the chosen art direction in the chosen scope? If not, name what has to flex (usually scope down or merge two mechanics into one). * Is there a hidden multiplayer requirement? ("4-player" or "co-op" anywhere = stop, multiplayer is its own scope explosion.) * Is the art direction generatable / sourceable for a solo dev? (Photoreal 3D for a 4-week vertical slice is a red flag.) If you spot a problem, raise it once, plainly: > One concern: \. Suggest \. OK or do you want to push through anyway? ### 8. Draft the brief Compose the 1-page brief. Format: ```markdown theme={null} # **Pitch:** **Core loop (30s):** **Three mechanics:** 1. 2. <…> 3. <…> **Art direction (one phrase):** <…> **Scope:** **Win condition:** **One thing this is NOT:** **Inspirations:** <2-4 specific games, films, or images.> **Parked for later:** ``` ### 9. Ask permission and write **Preferred (Summer MCP):** > May I create `.summer/GameSoul.md` with this brief? On yes, use guarded `summer_write_file` — `.summer/GameSoul.md` is plain markdown but still belongs to the bound project: ``` summer_write_file path="res://.summer/GameSoul.md" create_only=true content="" ``` If `.summer/GameSoul.md` already exists, read it first, show what would change, ask: > `.summer/GameSoul.md` already exists. May I overwrite it, or merge into a "Revision 2" section below the existing brief? **Fallback (Summer MCP unavailable — agent is read-only):** Print the full brief to the user with the explicit instruction: > Save this as `.summer/GameSoul.md` in your project root. Every Summer skill reads it. ### 10. Route to the next step End every successful brainstorm with a routing question: > Brief saved. Next step: > > * `/design-mechanic` — design the core loop in detail (recommended for vertical slice). > * `/design-level` — sketch level 1 / the tutorial. > * `/art-direction` — turn the one-phrase look into an art bible. > * Or pick up `/make-game` to start scaffolding the project. Don't auto-pick. Let them decide. ## Anti-patterns (don't do these) | Anti-pattern | Why it fails | | - | - | | Asking 6 questions in a row before any branching | User feels interviewed, not collaborated with. Branch after each answer. | | Letting them list 5+ mechanics | Three is the constraint. Without the constraint, the brief is useless. | | Skipping the "one thing this is NOT" line | This is the single best scope-protection in the brief. Future "let's add X" gets compared against it. | | Writing the brief without showing it first | They have to react to it. They'll catch their own bad fits when they read it back. | | Defaulting to "full game" scope | New devs overestimate. Default to vertical slice; let them upgrade if they push. | | Pitching a genre they didn't ask for | The first sentence they typed is signal. Don't override it. | | Including art direction details | One phrase. Bible-building is `/art-direction`. | | Saving without asking | Always ask "May I create `.summer/GameSoul.md`?" — see collaborative-protocol. | ## Collaborative protocol This skill writes one file (`.summer/GameSoul.md`). Always ask before writing. Always show the brief inline before saving so the user can react. ## Want a working starter? No template — this is a workflow that produces the brief that drives template selection later. Once `.summer/GameSoul.md` exists, `/make-game` reads it and `summer list templates` shows what's actually available to match against. ## See also * `design-mechanic` — design the core loop in detail * `design-level` — sketch level 1 * `art-direction` — turn the one-phrase look into a full bible * `audio-direction` — sonic identity * `make-game` — scaffold the project once the brief is locked ## From a shell No Summer MCP tools in this session? Run each one as a command; when `summer --version` is missing or below 4.0, use `npx -y summer-engine@latest` in place of `summer`. Fields are flags in kebab-case (`--scene-path res://main.tscn`) or one `--input ''`, and `summer ops describe ` prints the exact input. The `summer-cli` skill has the rest. | In this skill | Command | | - | - | | `summer_get_project_context` | `summer engine get-project-context` | | `summer_get_scene_tree` | `summer engine get-scene-tree` | | `summer_read_file` | `summer engine read-file` | | `summer_write_file` | `summer engine write-file` | ## Related skills * [`audio-direction`](/skills/audio-direction): Define the game's sound (music style, SFX vocabulary, dynamic music) as .summer/audio-bible.md. * [`design-mechanic`](/skills/design-mechanic): Design one mechanic in detail (input, feedback, failure modes, tunables) as a doc plus a script stub. * [`design-level`](/skills/design-level): Design one level (layout, pacing, encounters, secrets) as a design doc plus a node-tree skeleton. * [`art-direction`](/skills/art-direction): Define the game's visual style (palette, mood, lighting, post) as an art bible in .summer/art-bible.md. * [`make-game`](/skills/make-game): Orchestrate 'make me a game': brainstorm, plan, scaffold, mechanics, art, audio, polish, verify, ship. *** Source: [`library/skills/brainstorm-game/SKILL.md`](https://github.com/SummerEngine/summer/blob/main/library/skills/brainstorm-game/SKILL.md), rendered from `summer-engine@4.3.0` on npm. 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